`, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter

[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8,"_9":10},"actionData","errors","root",{"_373":374,"_375":376},"routes/_app.x.$handle.$name",{"_101":100,"_32":46,"_110":91,"_27":111,"_13":14,"_112":-5,"_11":113,"_114":115,"_116":117,"_118":119,"_120":121,"_20":-5,"_122":-5,"_123":-5,"_124":25,"_125":126,"_127":60,"_128":-5,"_129":-5,"_130":131},"routes/_app.x.$handle.$name.branch.$branch.version.$version.diff",{"_11":12,"_13":14,"_15":16,"_17":-5,"_18":-5},"project",{"_44":45,"_32":46,"_39":47,"_48":-5,"_49":25,"_50":51,"_52":51,"_53":54,"_55":-5,"_18":56,"_57":58,"_59":60,"_61":-5,"_62":-5,"_63":64,"_65":66,"_67":68,"_69":70,"_71":72,"_73":-5,"_74":75,"_76":75,"_77":78,"_79":78,"_80":78,"_81":75,"_82":75,"_83":84,"_85":86,"_87":88,"_89":25},"version",54,"changes",[19],"aiChatInfo","userId",{"_20":21,"_22":23,"_24":25,"_26":25,"_27":28,"_29":28},"file",{"_30":31,"_32":33,"_34":35,"_36":38,"_39":40,"_41":14,"_42":43,"_24":25},"previous",{"_30":31,"_32":33,"_34":35,"_36":37},"deleted",false,"deletedHere","path","backend/rhythms-data.ts","latestPath","fileId","fd91b3cc-a6f6-11f1-9d6d-1607ee4eb77e","name","rhythms-data.ts","fileType","script","content","// Standard nursing/EMS EKG curriculum — 20 core rhythms.\n// free: true rhythms are visible without a Pro unlock.\nexport interface Question {\n prompt: string;\n choices: string[ {\n id: \"atrial-bigeminy\",\n name: \"Atrial Bigeminy\",\n category: \"Atrial\",\n free: false,\n sortOrder: 29,\n rate: \"Underlying sinus rate variable; every other beat is an early PAC, so overall rate often looks near-normal to mildly irregular\",\n regularity: \"Regularly irregular — patterned couplet of sinus beat + PAC repeating\",\n pWave: \"Alternating normal sinus P wave and a premature, differently-shaped ectopic P wave\",\n prInterval: \"Sinus beats normal (0.12-0.20s); ectopic P wave PR interval often shortened or variable\",\n qrs: \"Narrow (<0.12s) unless the PAC is aberrantly conducted\",\n summary: \"An irritable atrial focus fires prematurely after every normal sinus beat, producing a repeating two-beat pattern of 'normal-early, normal-early.'\",\n clinicalNote: \"Usually benign and related to caffeine, stress, or stretch (e.g., atrial enlargement); frequent bigeminy can herald atrial fibrillation and warrants clinical correlation, not automatic treatment.\",\n waveform: { pattern: \"patternedEctopy\", unit: 2, ectopicSubtype: \"atrial\", baseRateMin: 70, baseRateMax: 90 },\n questions: [\n {\n prompt: \"Atrial bigeminy describes a rhythm where:\",\n choices: [\"Every third beat is a PAC\", \"Every other beat is a PAC\", \"Two PACs occur in a row then a pause\", \"PACs occur randomly with no pattern\"],\n correctIndex: 1,\n explanation: \"Bigeminy means a 2-beat repeating pattern — one normal sinus beat followed by one premature atrial beat, repeating.\",\n },\n {\n prompt: \"A patient with new frequent atrial bigeminy should raise concern for eventual progression to:\",\n choices: [\"Third-degree AV block\", \"Atrial fibrillation\", \"Ventricular fibrillation\", \"Sinus arrest\"],\n correctIndex: 1,\n explanation: \"Frequent atrial ectopy, including bigeminy, is a recognized precursor pattern for atrial fibrillation.\",\n },\n ],\n },\n {\n id: \"atrial-trigeminy\",\n name: \"Atrial Trigeminy\",\n category: \"Atrial\",\n free: false,\n sortOrder: 30,\n rate: \"Variable underlying sinus rate\",\n regularity: \"Regularly irregular — repeating 3-beat group (two sinus beats + one PAC)\",\n pWave: \"Two consecutive normal P waves followed by one premature/abnormally-shaped P wave, repeating\",\n prInterval: \"Normal for sinus beats; variable for the ectopic beat\",\n qrs: \"Narrow unless aberrant conduction present\",\n summary: \"Similar mechanism to atrial bigeminy but the ectopic atrial focus fires every third beat instead of every other beat, creating a repeating triplet grouping.\",\n clinicalNote: \"Typically benign; assess for stimulant use, hyperthyroidism, electrolyte disturbance, or structural atrial disease if frequent or symptomatic.\",\n waveform: { pattern: \"patternedEctopy\", unit: 3, ectopicSubtype: \"atrial\", baseRateMin: 70, baseRateMax: 90 },\n questions: [\n {\n prompt: \"What distinguishes trigeminy from bigeminy?\",\n choices: [\"Trigeminy has 3 PACs in a row\", \"Trigeminy repeats every 3rd beat instead of every 2nd\", \"Trigeminy only occurs in the ventricles\", \"Trigeminy is always pathologic\"],\n correctIndex: 1,\n explanation: \"The repeating group size is three beats in trigeminy versus two in bigeminy.\",\n },\n {\n prompt: \"Isolated atrial trigeminy in an asymptomatic patient with no structural heart disease typically requires:\",\n choices: [\"Emergent cardioversion\", \"No specific treatment, address triggers\", \"Immediate pacemaker\", \"IV amiodarone\"],\n correctIndex: 1,\n explanation: \"Benign ectopy in a structurally normal heart is usually managed by addressing triggers (caffeine, stress) rather than pharmacologic or electrical intervention.\",\n },\n ],\n },\n {\n id: \"pvc-bigeminy\",\n name: \"PVC Bigeminy (Ventricular Bigeminy)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 31,\n rate: \"Underlying rate variable; effective pulse rate may be lower if PVCs are non-perfusing\",\n regularity: \"Regularly irregular — repeating pattern of one normal beat then one PVC\",\n pWave: \"Normal sinus P wave on the sinus beat; no related P wave before the PVC\",\n prInterval: \"Normal on sinus beats; not applicable to the PVC\",\n qrs: \"Narrow on sinus beats; wide (>0.12s), bizarre-shaped on every other beat (the PVC)\",\n summary: \"A ventricular ectopic focus fires after every normal beat, producing an alternating pattern of one narrow sinus complex and one wide, premature ventricular complex.\",\n clinicalNote: \"Can occur in normal hearts but frequent bigeminy (especially with a PVC burden >10-15%) is associated with PVC-induced cardiomyopathy over time and warrants further workup.\",\n waveform: { pattern: \"patternedEctopy\", unit: 2, ectopicSubtype: \"ventricular\", baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"On palpation, PVC bigeminy classically feels like:\",\n choices: [\"A perfectly regular pulse\", \"Every other beat is weak or dropped\", \"A slow, regular bradycardia\", \"No palpable pulse at all\"],\n correctIndex: 1,\n explanation: \"Because PVCs often don't generate an adequate stroke volume, alternating strong/weak beats can be felt.\",\n },\n {\n prompt: \"A sustained high PVC burden over months is most associated with:\",\n choices: [\"Improved ejection fraction\", \"PVC-induced cardiomyopathy\", \"Resolution of hypertension\", \"Guaranteed benign outcome\"],\n correctIndex: 1,\n explanation: \"Chronic, frequent PVCs can lead to a reversible dilated cardiomyopathy if the burden is high enough and untreated.\",\n },\n ],\n },\n {\n id: \"pvc-trigeminy\",\n name: \"PVC Trigeminy (Ventricular Trigeminy)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 32,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Regularly irregular — repeating 3-beat group (two normal beats + one PVC)\",\n pWave: \"Normal P waves precede the sinus beats; none associated with the PVC\",\n prInterval: \"Normal on sinus beats\",\n qrs: \"Narrow x2 then one wide, bizarre PVC, repeating\",\n summary: \"A ventricular ectopic focus discharges every third beat, producing a repeating triplet of two normal conducted beats followed by one premature wide complex.\",\n clinicalNote: \"Same clinical considerations as bigeminy — evaluate PVC burden, symptoms, and underlying structural heart disease or electrolyte abnormality (especially hypokalemia/hypomagnesemia).\",\n waveform: { pattern: \"patternedEctopy\", unit: 3, ectopicSubtype: \"ventricular\", baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"A repeating pattern of two normal QRS complexes followed by one wide bizarre complex describes:\",\n choices: [\"PVC bigeminy\", \"PVC trigeminy\", \"Ventricular tachycardia\", \"Torsades de pointes\"],\n correctIndex: 1,\n explanation: \"The three-beat repeating group (2 normal + 1 PVC) is the defining feature of trigeminy.\",\n },\n {\n prompt: \"Which electrolyte disturbances commonly increase ventricular ectopy such as trigeminy?\",\n choices: [\"Hyperkalemia and hypercalcemia\", \"Hypokalemia and hypomagnesemia\", \"Hypernatremia and hypocalcemia\", \"None, electrolytes are unrelated\"],\n correctIndex: 1,\n explanation: \"Low potassium and low magnesium increase myocardial irritability and are classic reversible triggers for PVCs.\",\n },\n ],\n },\n {\n id: \"pvc-couplet\",\n name: \"PVC Couplet (Paired PVCs)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 33,\n rate: \"Underlying sinus rate variable; the couplet itself occurs rapidly\",\n regularity: \"Irregular — two consecutive PVCs occur back-to-back\",\n pWave: \"None associated with either PVC\",\n prInterval: \"Not applicable to the couplet beats\",\n qrs: \"Two consecutive wide, bizarre complexes with no normal beat in between, followed by a compensatory pause\",\n summary: \"Two PVCs fire consecutively without an intervening sinus beat, representing a brief run of ventricular ectopy one beat short of being called a 'run' (three or more defines non-sustained VT).\",\n clinicalNote: \"Couplets are more concerning than isolated PVCs because they signal increased ventricular irritability and a higher likelihood of progressing to sustained ventricular tachycardia.\",\n waveform: { pattern: \"burstEctopy\", burstLength: 2, baseRateMin: 65, baseRateMax: 85, burstRateMin: 150, burstRateMax: 180 },\n questions: [\n {\n prompt: \"A PVC couplet is defined as:\",\n choices: [\"One PVC followed by a pause\", \"Two consecutive PVCs in a row\", \"Three or more consecutive PVCs\", \"A PVC that lands on a T wave\"],\n correctIndex: 1,\n explanation: \"A couplet is specifically two back-to-back PVCs; three or more in a row is termed a run.\",\n },\n {\n prompt: \"Compared to isolated unifocal PVCs, PVC couplets carry:\",\n choices: [\"The same clinical significance\", \"Lower risk of progressing to VT\", \"Higher risk of progressing to VT\", \"No clinical significance\"],\n correctIndex: 2,\n explanation: \"Couplets indicate greater myocardial irritability and a higher likelihood of degenerating into sustained ventricular arrhythmias.\",\n },\n ],\n },\n {\n id: \"pvc-triplet-nsvt\",\n name: \"PVC Triplet / Non-Sustained Ventricular Tachycardia (NSVT)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 34,\n rate: \"Ventricular rate during the run typically 100-250 bpm\",\n regularity: \"The run itself is regular or near-regular; overall strip is irregular due to interruption of sinus rhythm\",\n pWave: \"None during the run; dissociated sinus P waves may be seen marching through\",\n prInterval: \"Not applicable during the run\",\n qrs: \"Three or more consecutive wide, bizarre complexes lasting <30 seconds and self-terminating\",\n summary: \"Three or more consecutive PVCs constitute a run of ventricular tachycardia; when it self-terminates within 30 seconds without hemodynamic collapse, it is classified as non-sustained VT.\",\n clinicalNote: \"NSVT in a structurally normal heart is often benign, but in the setting of prior MI, cardiomyopathy, or reduced ejection fraction it is a marker of increased risk for sudden cardiac death and warrants further evaluation.\",\n waveform: { pattern: \"burstEctopy\", burstLength: 5, baseRateMin: 65, baseRateMax: 85, burstRateMin: 160, burstRateMax: 220 },\n questions: [\n {\n prompt: \"How many consecutive PVCs are required to call a run \\\"ventricular tachycardia\\\" rather than a couplet?\",\n choices: [\"Two\", \"Three or more\", \"Five or more\", \"Ten or more\"],\n correctIndex: 1,\n explanation: \"Three or more consecutive ventricular beats at a rate over 100 bpm meets the definition of VT; a run lasting <30 seconds without collapse is termed non-sustained.\",\n },\n {\n prompt: \"NSVT is most clinically concerning when found in a patient with:\",\n choices: [\"A structurally normal heart and no symptoms\", \"Reduced ejection fraction after prior MI\", \"Well-controlled hypertension only\", \"Isolated caffeine use\"],\n correctIndex: 1,\n explanation: \"NSVT in structural heart disease, especially post-MI with reduced EF, is an independent risk marker for sudden cardiac death.\",\n },\n ],\n },\n {\n id: \"unifocal-pvcs\",\n name: \"Unifocal PVCs\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 35,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Irregular due to premature beats\",\n pWave: \"None associated with the PVCs\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, bizarre PVCs that are all identical in morphology to one another, arising from a single ventricular ectopic focus\",\n summary: \"All PVCs on the strip originate from the same irritable focus, so each one looks identical in shape, width, and axis.\",\n clinicalNote: \"Generally considered lower risk than multifocal PVCs because a single consistent focus is more predictable and often more benign, though burden and underlying heart disease still matter.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", count: 3, baseRateMin: 65, baseRateMax: 90 },\n questions: [\n {\n prompt: \"Unifocal PVCs are characterized by:\",\n choices: [\"Varying shapes from beat to beat\", \"Identical morphology from beat to beat\", \"Occurring only in pairs\", \"Always being asymptomatic\"],\n correctIndex: 1,\n explanation: \"\\\"Unifocal\\\" means one origin site, so every PVC has the same QRS morphology.\",\n },\n {\n prompt: \"Compared to multifocal PVCs, unifocal PVCs are generally considered:\",\n choices: [\"More dangerous\", \"Less concerning, arising from a single stable focus\", \"Impossible to distinguish clinically\", \"Always caused by digoxin toxicity\"],\n correctIndex: 1,\n explanation: \"A single consistent ectopic focus is typically viewed as lower risk than multiple competing irritable foci.\",\n },\n ],\n },\n {\n id: \"multifocal-pvcs\",\n name: \"Multifocal PVCs\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 36,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Irregular\",\n pWave: \"None associated with the PVCs\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, bizarre PVCs with varying morphology and axis from beat to beat, indicating more than one ventricular ectopic focus\",\n summary: \"PVCs arise from two or more different irritable ventricular sites, so their shape, width, and direction differ from one PVC to the next on the same strip.\",\n clinicalNote: \"Multifocal PVCs suggest a more diffusely irritable or diseased myocardium (ischemia, electrolyte disturbance, hypoxia) and are generally regarded as higher risk than unifocal PVCs.\",\n waveform: { pattern: \"multifocal\", wide: true, rateMin: 65, rateMax: 90, irregular: true },\n questions: [\n {\n prompt: \"Multifocal PVCs are identified by:\",\n choices: [\"Same shape every time\", \"Different QRS morphologies from beat to beat\", \"Occurring exactly every other beat\", \"A narrow QRS complex\"],\n correctIndex: 1,\n explanation: \"Multiple ectopic foci produce PVCs with varying shapes and axes on the same tracing.\",\n },\n {\n prompt: \"Multifocal PVCs are most concerning as a sign of:\",\n choices: [\"Normal aging only\", \"Diffuse myocardial irritability from ischemia, hypoxia, or electrolyte imbalance\", \"Excellent cardiac health\", \"Vagal tone\"],\n correctIndex: 1,\n explanation: \"Multiple competing ectopic foci suggest a broader insult to the myocardium and carry higher clinical concern than a single stable focus.\",\n },\n ],\n },\n {\n id: \"r-on-t-phenomenon\",\n name: \"R-on-T Phenomenon\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 37,\n rate: \"Underlying rate variable\",\n regularity: \"Irregular; the PVC falls during the vulnerable period of the preceding beat's T wave\",\n pWave: \"None associated with the PVC\",\n prInterval: \"Not applicable\",\n qrs: \"A PVC whose R wave lands directly on the peak/downslope of the preceding T wave\",\n summary: \"When a premature ventricular beat strikes during the relative refractory period marked by the T wave, it can trigger reentry and precipitate ventricular tachycardia or fibrillation.\",\n clinicalNote: \"R-on-T PVCs are considered a higher-risk ectopy pattern, particularly in the setting of acute ischemia or a prolonged QT interval, and clinicians should watch closely for degeneration into VT/VF or torsades.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", count: 1, baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"R-on-T phenomenon describes a PVC that lands on:\",\n choices: [\"The P wave of the prior beat\", \"The T wave of the prior beat\", \"The QRS of the prior beat\", \"The isoelectric baseline\"],\n correctIndex: 1,\n explanation: \"The T wave represents the vulnerable period of ventricular repolarization; a PVC striking there risks precipitating a malignant arrhythmia.\",\n },\n {\n prompt: \"R-on-T is of greatest concern in a patient who also has:\",\n choices: [\"A short PR interval\", \"A prolonged QT interval or acute ischemia\", \"Sinus arrhythmia\", \"First-degree AV block\"],\n correctIndex: 1,\n explanation: \"A prolonged QT widens the vulnerable window, and acute ischemia increases myocardial irritability, both raising the risk that R-on-T triggers VT/VF or torsades.\",\n },\n ],\n },\n {\n id: \"ventricular-fusion-beat\",\n name: \"Ventricular Fusion Beat\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 38,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Occurs as an isolated irregular beat within an otherwise regular rhythm\",\n pWave: \"A sinus P wave is present, conducting simultaneously with a competing ventricular ectopic impulse\",\n prInterval: \"May appear shortened or normal depending on timing\",\n qrs: \"A single complex with a morphology intermediate between a normal narrow QRS and a wide bizarre PVC\",\n summary: \"A fusion beat happens when a supraventricular impulse and a ventricular ectopic impulse depolarize the ventricles simultaneously, blending their two QRS morphologies into one hybrid complex.\",\n clinicalNote: \"Fusion beats are a classic supportive finding for diagnosing ventricular tachycardia (a 'Dressler beat'), helping distinguish VT from SVT with aberrancy.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", count: 1, baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"A fusion beat results from:\",\n choices: [\"Two PVCs occurring simultaneously\", \"A sinus impulse and a ventricular ectopic impulse depolarizing the ventricle at the same time\", \"Complete AV block\", \"Atrial fibrillation with rapid response\"],\n correctIndex: 1,\n explanation: \"Fusion beats blend normal conduction with a competing ventricular ectopic focus into one intermediate-shaped complex.\",\n },\n {\n prompt: \"Finding fusion beats during a wide-complex tachycardia supports a diagnosis of:\",\n choices: [\"SVT with aberrancy\", \"Ventricular tachycardia\", \"Atrial flutter\", \"Sinus tachycardia\"],\n correctIndex: 1,\n explanation: \"Fusion (and capture) beats are classic AV dissociation clues that favor VT over SVT with aberrant conduction.\",\n },\n ],\n },\n {\n id: \"aberrantly-conducted-pac-ashman\",\n name: \"Aberrantly Conducted PAC (Ashman Phenomenon)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 39,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Irregular due to the premature beat\",\n pWave: \"A premature, differently-shaped P wave precedes the wide beat\",\n prInterval: \"Often shortened compared to sinus beats\",\n qrs: \"Wide and bizarre-looking (commonly RBBB morphology), mimicking a PVC, but preceded by a premature P wave\",\n summary: \"A PAC that arrives early, while part of the conduction system is still refractory from the preceding long cycle, conducts aberrantly and produces a wide QRS that mimics a PVC.\",\n clinicalNote: \"Recognizing Ashman phenomenon (classically a 'long-short' cycle sequence) prevents misdiagnosing a benign aberrantly conducted PAC as a dangerous PVC, and is frequently seen at the onset of atrial fibrillation.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"atrial\", wide: true, count: 1, baseRateMin: 70, baseRateMax: 90 },\n questions: [\n {\n prompt: \"Ashman phenomenon classically occurs after which cycle pattern?\",\n choices: [\"A short cycle followed by a long cycle\", \"A long cycle followed by a short cycle\", \"Two equal cycles in a row\", \"Complete pause with no preceding cycle\"],\n correctIndex: 1,\n explanation: \"A long R-R interval prolongs the refractory period of the bundle branches; a subsequent short-cycle beat can then conduct aberrantly.\",\n },\n {\n prompt: \"The key clue that a wide beat is an aberrantly conducted PAC rather than a true PVC is:\",\n choices: [\"A premature P wave preceding it with typical RBBB morphology\", \"A fully compensatory pause\", \"Absence of any P wave\", \"A fixed coupling interval\"],\n correctIndex: 0,\n explanation: \"Ashman-phenomenon beats are preceded by a premature ectopic P wave and often show a classic RBBB (rSR') pattern, distinguishing them from PVCs.\",\n },\n ],\n },\n {\n id: \"junctional-escape-beat\",\n name: \"Junctional Escape Beat\",\n category: \"Junctional\",\n free: false,\n sortOrder: 40,\n rate: \"A single beat occurring at the junctional escape rate (40-60 bpm) after a pause\",\n regularity: \"An isolated beat interrupting the underlying rhythm following a pause\",\n pWave: \"Absent, inverted, or retrograde\",\n prInterval: \"Short (<0.12s) if a retrograde P precedes the QRS, or not measurable if absent\",\n qrs: \"Narrow (<0.12s), normal in shape\",\n summary: \"When the sinus node fails to fire on time, the AV junction acts as a backup pacemaker and produces a single escape beat to prevent an excessively long pause.\",\n clinicalNote: \"A single junctional escape beat is a protective safety mechanism, not itself pathologic, but its presence signals underlying sinus node dysfunction that should be evaluated.\",\n waveform: { pattern: \"pause\", rateMin: 60, rateMax: 90, hasPWave: true, prMs: 160 },\n questions: [\n {\n prompt: \"A junctional escape beat occurs because:\",\n choices: [\"The junction is diseased and firing too fast\", \"The sinus node failed to fire on time and a backup pacemaker took over for one beat\", \"The patient has WPW\", \"It follows a PVC always\"],\n correctIndex: 1,\n explanation: \"Escape beats are a protective backup mechanism that fires after the sinus node pauses too long.\",\n },\n {\n prompt: \"A single junctional escape beat should prompt evaluation for:\",\n choices: [\"Nothing, it's always normal\", \"Underlying sinus node dysfunction\", \"Ventricular fibrillation risk\", \"Digoxin toxicity only\"],\n correctIndex: 1,\n explanation: \"While the escape beat itself is protective, its occurrence indicates the sinus node paused, warranting evaluation of sinus node function.\",\n },\n ],\n },\n {\n id: \"ventricular-escape-beat\",\n name: \"Ventricular Escape Beat\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 41,\n rate: \"A single beat at the ventricular escape rate (20-40 bpm) following a pause\",\n regularity: \"An isolated beat interrupting the underlying rhythm after a long pause\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"Wide (>0.12s), bizarre morphology, occurring late after a pause\",\n summary: \"When both the sinus node and the AV junction fail to initiate an impulse in time, a ventricular pacemaker cell fires as a last-resort backup to prevent asystole.\",\n clinicalNote: \"A ventricular escape beat is a life-sustaining safety mechanism; its appearance indicates significant conduction system disease and often precedes a need for pacing.\",\n waveform: { pattern: \"pause\", rateMin: 55, rateMax: 80, hasPWave: true, prMs: 160 },\n questions: [\n {\n prompt: \"A ventricular escape beat appears when:\",\n choices: [\"Both the SA node and AV junction fail to fire in time\", \"The atria are fibrillating\", \"A PVC lands on a T wave\", \"The patient is in normal sinus rhythm\"],\n correctIndex: 0,\n explanation: \"Ventricular escape is the heart's last line of defense, firing only when higher pacemakers (SA node, AV junction) fail to initiate an impulse.\",\n },\n {\n prompt: \"The presence of ventricular escape beats most strongly suggests the need to evaluate for:\",\n choices: [\"Simple sinus arrhythmia\", \"Significant conduction system disease requiring possible pacing\", \"Benign PACs\", \"Athletic heart syndrome\"],\n correctIndex: 1,\n explanation: \"Reliance on a ventricular escape mechanism reflects failure of both higher-order pacemakers and often signals a need for permanent pacing.\",\n },\n ],\n },\n {\n id: \"atrial-escape-beat\",\n name: \"Atrial Escape Beat\",\n category: \"Atrial\",\n free: false,\n sortOrder: 42,\n rate: \"A single beat occurring after a pause, originating from an ectopic atrial focus\",\n regularity: \"An isolated beat interrupting the underlying rhythm following a pause\",\n pWave: \"Present but abnormally shaped since it originates from an ectopic atrial site, not the SA node\",\n prInterval: \"May be normal or slightly different from sinus PR interval\",\n qrs: \"Narrow, normal conduction\",\n summary: \"When the SA node pauses, a subsidiary atrial pacemaker outside the sinus node fires to prevent a longer pause, producing a single beat with a differently shaped P wave but otherwise normal narrow QRS.\",\n clinicalNote: \"Like junctional escape, this is a protective mechanism reflecting transient SA node under-function rather than a primary arrhythmia requiring emergent treatment.\",\n waveform: { pattern: \"pause\", rateMin: 60, rateMax: 90, hasPWave: true, prMs: 150 },\n questions: [\n {\n prompt: \"An atrial escape beat differs from a PAC in that it:\",\n choices: [\"Comes early\", \"Comes late, after a pause, as a protective response\", \"Always has a wide QRS\", \"Never has a P wave\"],\n correctIndex: 1,\n explanation: \"A PAC is premature (early); an escape beat is, by definition, late — it fires only after the primary pacemaker fails to fire on time.\",\n },\n {\n prompt: \"The QRS of an atrial escape beat is typically:\",\n choices: [\"Wide and bizarre\", \"Narrow, since conduction through the AV node and ventricles is normal\", \"Absent entirely\", \"Always preceded by no P wave\"],\n correctIndex: 1,\n explanation: \"Since the impulse still originates above the ventricles and conducts normally through the His-Purkinje system, the QRS remains narrow.\",\n },\n ],\n },\n {\n id: \"hyperkalemia-ecg-changes\",\n name: \"Hyperkalemia ECG Pattern\",\n category: \"Other\",\n free: false,\n sortOrder: 43,\n rate: \"Variable; sinus rate may slow as severity increases\",\n regularity: \"Regular initially, progressing to irregular as severity worsens\",\n pWave: \"Flattened and widened, eventually disappearing as potassium rises further\",\n prInterval: \"Progressively prolonged, then P waves are lost\",\n qrs: \"Progressively widens; in severe hyperkalemia the QRS merges with the T wave (sine-wave pattern)\",\n summary: \"Rising extracellular potassium progressively depresses cardiac conduction velocity, producing a characteristic sequence from tall peaked T waves, to PR prolongation and flattened P waves, to QRS widening.\",\n clinicalNote: \"This is a true cardiac emergency — severity of ECG change (not the lab potassium value alone) should guide urgency of treatment with IV calcium, insulin/dextrose, and other potassium-lowering measures.\",\n waveform: { pattern: \"regular\", rateMin: 50, rateMax: 80, hasPWave: true, wide: true, prMs: 220, tAmpScale: 2.2 },\n questions: [\n {\n prompt: \"The earliest classic ECG change of hyperkalemia is:\",\n choices: [\"Widened QRS\", \"Tall, peaked, narrow-based T waves\", \"Sine wave pattern\", \"Prolonged QT\"],\n correctIndex: 1,\n explanation: \"Peaked, tented T waves are typically the earliest sign, appearing before P wave flattening and QRS widening.\",\n },\n {\n prompt: \"A sine-wave pattern on ECG in a hyperkalemic patient indicates:\",\n choices: [\"Mild, non-urgent hyperkalemia\", \"Life-threatening hyperkalemia requiring immediate treatment\", \"Normal variant\", \"Digoxin effect\"],\n correctIndex: 1,\n explanation: \"The sine-wave pattern represents merging of the widened QRS with the T wave and is a pre-terminal rhythm requiring emergent calcium administration and potassium-lowering therapy.\",\n },\n ],\n },\n];\n correctIndex: number;\n explanation: string;\n}\n\n// Machine-readable description of what a rhythm strip looks like, used by\n// frontend/lib/waveform.ts to synthesize a fresh, slightly-randomized strip\n// on every practice round (not a literal clinical tracing — a teaching\n// approximation of rate, regularity, P-wave presence, and QRS width/shape).\nexport type WaveformPattern =\n | \"regular\"\n | \"ectopic\"\n | \"patternedEctopy\"\n | \"burstEctopy\"\n | \"parasystole\"\n | \"tachyBrady\"\n | \"failToCapture\"\n | \"failToSense\"\n | \"idioventricularCapture\"\n | \"afib\"\n | \"aflutter\"\n | \"wenckebach\"\n | \"type2block\"\n | \"thirdDegree\"\n | \"torsades\"\n | \"chaotic\"\n | \"flatline\"\n | \"pause\"\n | \"multifocal\";\n\nexport interface WaveformSpec {\n pattern: WaveformPattern;\n rateMin?: number;\n rateMax?: number;\n hasPWave?: boolean;\n wide?: boolean;\n prMs?: number;\n ectopicSubtype?: \"atrial\" | \"junctional\" | \"ventricular\";\n baseRateMin?: number;\n baseRateMax?: number;\n atrialRate?: number;\n ratios?: number[];\n startPrMs?: number;\n prIncrementMs?: number;\n cycleBeats?: number;\n dropEvery?: number;\n atrialRateMin?: number;\n atrialRateMax?: number;\n ventricularRateMin?: number;\n ventricularRateMax?: number;\n irregular?: boolean;\n delta?: boolean;\n pacedSpike?: boolean;\n // Extended fields for the expanded (100+) library — patterned/burst ectopy,\n // electrolyte/drug/device effects, and simple visual modifiers reused by\n // the 12-lead grid. All are optional teaching approximations, not literal\n // clinical tracings.\n count?: number; // how many ectopic beats to insert (unifocal/multifocal PVCs)\n unit?: number; // patternedEctopy: 2 = bigeminy, 3 = trigeminy\n burstLength?: number; // burstEctopy: couplet=2, triplet/NSVT=3+\n burstRateMin?: number;\n burstRateMax?: number;\n qDeep?: boolean; // exaggerated pathologic Q wave\n tAmpScale?: number; // T-wave amplitude multiplier (peaked/flattened T)\n tInvert?: boolean; // flip T-wave polarity\n qtOffsetMs?: number; // shift T-wave center (long/short QT)\n uWave?: boolean; // add a small U wave after the T\n stScoop?: boolean; // digoxin-effect ST sag\n stElevation?: boolean; // ST elevation bump\n stDepression?: boolean; // ST depression dip\n osbornWave?: boolean; // hypothermia J wave\n ampScale?: number; // global amplitude multiplier (low voltage)\n alternans?: boolean; // alternating beat-to-beat amplitude\n interference?: boolean; // fine AC-interference overlay\n}\n\nexport interface Rhythm {\n id: string;\n name: string;\n category: \"Sinus\" | \"Atrial\" | \"Junctional\" | \"AV Block\" | \"Ventricular\" | \"Other\";\n free: boolean;\n sortOrder: number;\n rate: string;\n regularity: string;\n pWave: string;\n prInterval: string;\n qrs: string;\n summary: string;\n clinicalNote: string;\n waveform: WaveformSpec;\n questions: Question[];\n}\n\nexport const RHYTHMS: Rhythm[] = [\n {\n id: \"nsr\",\n name: \"Normal Sinus Rhythm\",\n category: \"Sinus\",\n free: true,\n sortOrder: 1,\n rate: \"60-100 bpm\",\n regularity: \"Regular\",\n pWave: \"Present, upright, one before every QRS\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"The baseline rhythm every other rhythm is compared against — originates in the SA node, conducts normally through the AV node.\",\n clinicalNote: \"No intervention needed. This is the rhythm you're confirming is present, not absent, before worrying about anything else on the strip.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: true, wide: false, prMs: 160 },\n questions: [\n {\n prompt: \"A patient's monitor shows a rate of 78, regular, with an upright P wave before every QRS and a PR interval of 0.16s. What is this rhythm?\",\n choices: [\"Normal Sinus Rhythm\", \"Sinus Tachycardia\", \"First-Degree AV Block\", \"Junctional Rhythm\"],\n correctIndex: 0,\n explanation: \"Rate 60-100, regular, P before every QRS, normal PR interval — textbook NSR.\",\n },\n {\n prompt: \"Which feature, if it were missing, would rule OUT normal sinus rhythm?\",\n choices: [\"A narrow QRS\", \"An upright P wave before every QRS\", \"A rate under 150\", \"A regular rhythm\"],\n correctIndex: 1,\n explanation: \"Sinus rhythms are defined by the P wave originating from the SA node and preceding every QRS — lose that relationship and it's no longer sinus.\",\n },\n ],\n },\n {\n id: \"sinus-brady\",\n name: \"Sinus Bradycardia\",\n category: \"Sinus\",\n free: true,\n sortOrder: 2,\n rate: \"<60 bpm\",\n regularity: \"Regular\",\n pWave: \"Present, upright, one before every QRS\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"Same conduction pattern as NSR, just slower than 60. Can be normal (athletes, sleep) or pathologic (meds, sick sinus syndrome, hypothyroidism).\",\n clinicalNote: \"Only treat if symptomatic (hypotension, altered mental status, chest pain) — a healthy resting rate of 48 in a fit patient needs no intervention.\",\n waveform: { pattern: \"regular\", rateMin: 40, rateMax: 59, hasPWave: true, wide: false, prMs: 160 },\n questions: [\n {\n prompt: \"A rhythm strip shows a rate of 44, regular, normal P waves and PR interval, narrow QRS. The patient is alert, talking, and has a normal blood pressure. What's the priority action?\",\n choices: [\"Give atropine immediately\", \"Start transcutaneous pacing\", \"Monitor — this may not require treatment if asymptomatic\", \"Perform synchronized cardioversion\"],\n correctIndex: 2,\n explanation: \"Sinus bradycardia is only treated when it's causing symptoms. An asymptomatic, hemodynamically stable patient just gets monitored.\",\n },\n {\n prompt: \"Which of these is a common non-pathologic cause of sinus bradycardia?\",\n choices: [\"Third-degree AV block\", \"High level of physical conditioning (athlete's heart)\", \"Digoxin toxicity\", \"Hyperthyroidism\"],\n correctIndex: 1,\n explanation: \"Well-conditioned athletes often have resting rates in the 40s-50s from high vagal tone and stroke volume — a normal finding, not a block.\",\n },\n ],\n },\n {\n id: \"sinus-tach\",\n name: \"Sinus Tachycardia\",\n category: \"Sinus\",\n free: true,\n sortOrder: 3,\n rate: \">100 bpm\",\n regularity: \"Regular\",\n pWave: \"Present, upright, one before every QRS\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"Normal conduction, just faster than 100 — almost always a response to something else (pain, fever, dehydration, anxiety, blood loss), not a primary cardiac problem.\",\n clinicalNote: \"Treat the cause, not the rate — find and fix why the heart is compensating (fluids for dehydration, pain control, treat the fever) rather than trying to slow it directly.\",\n waveform: { pattern: \"regular\", rateMin: 101, rateMax: 150, hasPWave: true, wide: false, prMs: 140 },\n questions: [\n {\n prompt: \"A trauma patient's monitor shows a regular rhythm at 128 bpm with normal P waves and narrow QRS. What should you look for first?\",\n choices: [\"A drug that blocks the AV node\", \"A source of blood loss, pain, or hypoxia driving the rate up\", \"Evidence of a missed P wave\", \"A prolonged QT interval\"],\n correctIndex: 1,\n explanation: \"Sinus tach is almost always secondary to something — in trauma, think hemorrhage first. Slowing the rate directly (e.g. a beta blocker) without fixing the cause can be dangerous.\",\n },\n {\n prompt: \"What distinguishes sinus tachycardia from SVT on a monitor?\",\n choices: [\"Sinus tach has no visible P waves\", \"Sinus tach rarely exceeds 220 bpm and P waves are visible before each QRS\", \"Sinus tach always requires adenosine\", \"Sinus tach has a wide QRS\"],\n correctIndex: 1,\n explanation: \"Sinus tach retains normal P waves and typically tops out lower than SVT, which is often faster and can obscure or hide the P wave in the preceding T wave.\",\n },\n ],\n },\n {\n id: \"pac\",\n name: \"Premature Atrial Contraction (PAC)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 4,\n rate: \"Underlying rhythm rate, with early beats\",\n regularity: \"Irregular (early beat interrupts the pattern)\",\n pWave: \"Early, and often a different shape than the sinus P wave\",\n prInterval: \"May be shorter or longer than normal\",\n qrs: \"Usually narrow (unless aberrantly conducted)\",\n summary: \"An ectopic focus in the atria fires before the SA node's next scheduled beat, causing an early beat with an abnormal-looking P wave.\",\n clinicalNote: \"Usually benign — caffeine, stress, and stimulants are common triggers. Frequent PACs can sometimes signal developing atrial fibrillation.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"atrial\", baseRateMin: 60, baseRateMax: 90 },\n questions: [\n {\n prompt: \"On an otherwise regular strip, one beat arrives early with a P wave that looks different from the others, followed by a normal QRS. What is this?\",\n choices: [\"Premature Ventricular Contraction\", \"Premature Atrial Contraction\", \"Second-degree AV block\", \"Atrial flutter\"],\n correctIndex: 1,\n explanation: \"An early beat with an abnormally-shaped (but present) P wave and a normal QRS is the signature of a PAC — the ectopic focus is atrial, not ventricular.\",\n },\n {\n prompt: \"A patient asks if their occasional PACs, found on a routine monitor, are dangerous. What's the most accurate response?\",\n choices: [\"They always require immediate cardioversion\", \"They're usually benign, often triggered by caffeine or stress, though frequent PACs are worth monitoring\", \"They mean the patient is in cardiac arrest\", \"They can only be caused by a heart attack\"],\n correctIndex: 1,\n explanation: \"Occasional PACs are common and usually harmless. It's a pattern of frequent PACs, not an isolated one, that occasionally warrants a closer look for developing afib.\",\n },\n ],\n },\n {\n id: \"afib\",\n name: \"Atrial Fibrillation\",\n category: \"Atrial\",\n free: true,\n sortOrder: 5,\n rate: \"Variable (ventricular response can be slow, controlled, or rapid)\",\n regularity: \"Irregularly irregular\",\n pWave: \"Absent — replaced by chaotic fibrillatory waves\",\n prInterval: \"Not measurable (no discrete P wave)\",\n qrs: \"Usually narrow\",\n summary: \"Multiple chaotic atrial foci fire simultaneously instead of one coordinated SA node signal, so the atria quiver rather than contract, and the ventricles respond irregularly.\",\n clinicalNote: \"The classic teaching point is 'irregularly irregular' with no true P waves. Stroke risk from atrial clot formation is the major long-term concern, not just the rhythm itself.\",\n waveform: { pattern: \"afib\", rateMin: 70, rateMax: 150 },\n questions: [\n {\n prompt: \"A strip shows no identifiable P waves, a chaotic baseline, and an R-R interval that varies with no repeating pattern. What is this rhythm?\",\n choices: [\"Sinus Arrhythmia\", \"Atrial Flutter\", \"Atrial Fibrillation\", \"Third-degree AV block\"],\n correctIndex: 2,\n explanation: \"Absent P waves plus an irregularly irregular rhythm (no predictable pattern at all, unlike flutter's often-regular ratios) is the defining picture of afib.\",\n },\n {\n prompt: \"Why is atrial fibrillation clinically significant beyond the rhythm itself?\",\n choices: [\"It always causes immediate cardiac arrest\", \"The quivering atria don't empty fully, raising the risk of clot formation and stroke\", \"It permanently damages the AV node\", \"It cannot occur in otherwise healthy people\"],\n correctIndex: 1,\n explanation: \"Blood pooling in the poorly-contracting atria can clot; if that clot embolizes, it can cause a stroke — this is why anticoagulation is a major part of afib management.\",\n },\n ],\n },\n {\n id: \"aflutter\",\n name: \"Atrial Flutter\",\n category: \"Atrial\",\n free: false,\n sortOrder: 6,\n rate: \"Atrial rate ~250-350 bpm; ventricular rate depends on conduction ratio\",\n regularity: \"Often regular (fixed conduction ratio) but can be irregular (variable conduction)\",\n pWave: \"Sawtooth ('flutter') waves, no isoelectric baseline\",\n prInterval: \"Not measurable in the usual sense\",\n qrs: \"Usually narrow\",\n summary: \"A single reentrant circuit in the atria fires very rapidly and regularly, producing the classic sawtooth pattern; the AV node protects the ventricles by only conducting a fraction of those impulses through (commonly 2:1, 3:1, or 4:1).\",\n clinicalNote: \"Look for the sawtooth pattern, most visible in leads II, III, and aVF — a 2:1 conduction ratio can be easy to mistake for sinus tach if you don't count carefully.\",\n waveform: { pattern: \"aflutter\", atrialRate: 300, ratios: [2, 3, 4] },\n questions: [\n {\n prompt: \"A strip shows a sawtooth-shaped baseline at roughly 300 bpm with every other flutter wave conducting to the ventricles, giving a ventricular rate near 150. What is this rhythm?\",\n choices: [\"Atrial Fibrillation\", \"Atrial Flutter with 2:1 conduction\", \"Sinus Tachycardia\", \"Ventricular Tachycardia\"],\n correctIndex: 1,\n explanation: \"The sawtooth pattern at ~300 with a 2:1 AV conduction ratio (every other impulse getting through) producing a ventricular rate near 150 is the classic atrial flutter picture.\",\n },\n {\n prompt: \"What structure is responsible for protecting the ventricles from the very fast atrial rate in atrial flutter?\",\n choices: [\"The SA node\", \"The AV node, by not conducting every atrial impulse through\", \"The bundle of His\", \"The Purkinje fibers\"],\n correctIndex: 1,\n explanation: \"The AV node's refractory period limits how many of the rapid atrial impulses actually reach the ventricles — that's why the ventricular rate is a fraction of the atrial rate.\",\n },\n ],\n },\n {\n id: \"svt\",\n name: \"Supraventricular Tachycardia (SVT)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 7,\n rate: \"150-250 bpm\",\n regularity: \"Regular\",\n pWave: \"Often hidden in the preceding T wave or not visible\",\n prInterval: \"Not measurable if P waves aren't visible\",\n qrs: \"Narrow (unless aberrantly conducted)\",\n summary: \"An umbrella term for fast, regular rhythms originating above the ventricles, most commonly from a reentrant circuit involving the AV node — starts and stops abruptly.\",\n clinicalNote: \"Vagal maneuvers (bearing down, carotid massage by a trained provider) or adenosine are first-line treatments — both work by transiently blocking the AV node to interrupt the reentrant circuit.\",\n waveform: { pattern: \"regular\", rateMin: 150, rateMax: 220, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A patient reports their heart 'suddenly took off' and the monitor shows a narrow-complex rhythm at 180 bpm, perfectly regular, with no visible P waves. What is the most likely rhythm?\",\n choices: [\"Sinus Tachycardia\", \"Supraventricular Tachycardia (SVT)\", \"Ventricular Tachycardia\", \"Atrial Flutter with 4:1 conduction\"],\n correctIndex: 1,\n explanation: \"The abrupt onset, rate over 150-180 with no visible P waves, and regular narrow QRS is classic SVT — sinus tach ramps up gradually and rarely reaches this rate with hidden P waves.\",\n },\n {\n prompt: \"Why does adenosine work as a treatment for SVT?\",\n choices: [\"It permanently destroys the reentrant pathway\", \"It briefly blocks conduction through the AV node, interrupting the reentrant circuit\", \"It increases the atrial rate to override the SVT\", \"It widens the QRS complex\"],\n correctIndex: 1,\n explanation: \"Adenosine causes a very brief, complete AV node block — long enough to break the reentry loop that's sustaining the SVT, often resetting the rhythm back to sinus.\",\n },\n ],\n },\n {\n id: \"pjc\",\n name: \"Premature Junctional Contraction (PJC)\",\n category: \"Junctional\",\n free: false,\n sortOrder: 8,\n rate: \"Underlying rhythm rate, with early beats\",\n regularity: \"Irregular (early beat interrupts the pattern)\",\n pWave: \"Absent, inverted, or after the QRS (retrograde)\",\n prInterval: \"Short if a retrograde P wave is present\",\n qrs: \"Narrow\",\n summary: \"An early beat originating from the AV junction rather than the SA node or atria — the junction can conduct upward into the atria (inverted/retrograde P) as well as down to the ventricles.\",\n clinicalNote: \"Distinguish from a PAC by the P wave: absent, inverted, or appearing after the QRS rather than a normal upright P wave before it.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"junctional\", baseRateMin: 60, baseRateMax: 90 },\n questions: [\n {\n prompt: \"An early narrow QRS appears with no visible P wave before it, but there's a small inverted deflection just after the QRS. What best explains this beat?\",\n choices: [\"Premature Atrial Contraction\", \"Premature Junctional Contraction with a retrograde P wave\", \"Third-degree AV block\", \"Premature Ventricular Contraction\"],\n correctIndex: 1,\n explanation: \"A junctional beat can conduct backward into the atria, producing an inverted P wave that shows up after (or hidden within) the QRS rather than before it.\",\n },\n {\n prompt: \"What differentiates a PJC from a PAC on a strip?\",\n choices: [\"PJCs have a wide QRS and PACs don't\", \"PJCs lack a normal upright P wave before the QRS; PACs have an abnormal but present upright P wave before it\", \"PJCs are always symptomatic and PACs never are\", \"There is no meaningful difference\"],\n correctIndex: 1,\n explanation: \"The key distinction is the P wave: a PAC still has one before the QRS (just oddly shaped), while a PJC's P wave is absent, inverted, or retrograde.\",\n },\n ],\n },\n {\n id: \"junctional\",\n name: \"Junctional Rhythm\",\n category: \"Junctional\",\n free: false,\n sortOrder: 9,\n rate: \"40-60 bpm\",\n regularity: \"Regular\",\n pWave: \"Absent, inverted, or after the QRS\",\n prInterval: \"Short or not measurable\",\n qrs: \"Narrow\",\n summary: \"The AV junction takes over as the heart's pacemaker when the SA node fails to fire or its impulse doesn't reach the ventricles — an intrinsic 'backup' rate of 40-60.\",\n clinicalNote: \"Treat the underlying cause (often SA node dysfunction) rather than the rhythm itself if the patient is stable; symptomatic patients may need atropine or pacing, same as symptomatic bradycardia.\",\n waveform: { pattern: \"regular\", rateMin: 40, rateMax: 60, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A monitor shows a regular narrow-complex rhythm at 48 bpm with no visible P waves. What is the most likely rhythm?\",\n choices: [\"Sinus Bradycardia\", \"Junctional Rhythm\", \"Third-degree AV Block\", \"Idioventricular Rhythm\"],\n correctIndex: 1,\n explanation: \"A regular rate in the 40-60 range with a narrow QRS and no P waves points to the AV junction acting as the pacemaker, not the SA node (which would show P waves) or the ventricles (which would show a wide QRS).\",\n },\n {\n prompt: \"Why does a junctional rhythm typically run at 40-60 bpm rather than faster?\",\n choices: [\"That's the AV junction's own intrinsic backup pacing rate\", \"It's always a sign of digoxin toxicity\", \"The ventricles are pacing themselves at that rate\", \"It matches the SA node's normal rate\"],\n correctIndex: 0,\n explanation: \"The cardiac conduction system has tiered intrinsic backup rates — SA node fastest, AV junction next at 40-60, ventricles slowest — and junctional rhythm reflects the AV junction's own rate when it takes over.\",\n },\n ],\n },\n {\n id: \"accel-junctional\",\n name: \"Accelerated Junctional Rhythm\",\n category: \"Junctional\",\n free: false,\n sortOrder: 10,\n rate: \"60-100 bpm\",\n regularity: \"Regular\",\n pWave: \"Absent, inverted, or after the QRS\",\n prInterval: \"Short or not measurable\",\n qrs: \"Narrow\",\n summary: \"Same origin as a junctional rhythm, but the junction is firing faster than its normal 40-60 backup rate — often from irritability (ischemia, digoxin toxicity) rather than simple SA node failure.\",\n clinicalNote: \"A rate that's 'too fast' for a junctional escape rhythm (60-100 instead of 40-60) should prompt a look at digoxin levels and electrolytes.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A regular narrow-complex rhythm at 75 bpm shows no P waves before the QRS. What distinguishes this from a plain junctional rhythm?\",\n choices: [\"The QRS is wide\", \"The rate (60-100) is faster than the typical junctional escape rate of 40-60, making this accelerated junctional\", \"There's a visible sawtooth pattern\", \"The PR interval is prolonged\"],\n correctIndex: 1,\n explanation: \"The mechanism (AV junction pacing, no true P wave before QRS) is identical to junctional rhythm — the only difference is the faster rate, which earns it the 'accelerated' label.\",\n },\n {\n prompt: \"Accelerated junctional rhythm is classically associated with which of the following?\",\n choices: [\"Athletic conditioning\", \"Digoxin toxicity or myocardial irritability\", \"Caffeine intake\", \"Normal aging\"],\n correctIndex: 1,\n explanation: \"Unlike a slow junctional escape rhythm (often benign SA node failure), an accelerated junctional focus is often irritable tissue — digoxin toxicity is a classic teaching association.\",\n },\n ],\n },\n {\n id: \"first-degree\",\n name: \"First-Degree AV Block\",\n category: \"AV Block\",\n free: false,\n sortOrder: 11,\n rate: \"Underlying rhythm rate\",\n regularity: \"Regular\",\n pWave: \"Present, one before every QRS\",\n prInterval: \"Prolonged, >0.20s, but constant\",\n qrs: \"Narrow (unless a separate bundle branch issue exists)\",\n summary: \"Every atrial impulse still reaches the ventricles, but conduction through the AV node is delayed — so the PR interval is stretched out but stays constant beat to beat.\",\n clinicalNote: \"Usually benign and often an incidental finding — it's a delay, not a dropped beat, so no beats are lost. Worth noting on the chart and monitoring for progression, but rarely urgent on its own.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: true, wide: false, prMs: 280 },\n questions: [\n {\n prompt: \"A strip shows a P wave before every QRS, a regular rhythm, but the PR interval measures 0.28s on every beat. What is this rhythm?\",\n choices: [\"Second-Degree AV Block Type I\", \"Third-Degree AV Block\", \"First-Degree AV Block\", \"Normal Sinus Rhythm\"],\n correctIndex: 2,\n explanation: \"A consistently prolonged (>0.20s) but unchanging PR interval, with every P wave still conducting to a QRS, is the definition of first-degree AV block.\",\n },\n {\n prompt: \"What is the key difference between first-degree AV block and normal sinus rhythm?\",\n choices: [\"First-degree block drops occasional QRS complexes\", \"First-degree block has a prolonged but constant PR interval; NSR's PR interval is normal (0.12-0.20s)\", \"First-degree block has no P waves\", \"There is no real difference\"],\n correctIndex: 1,\n explanation: \"The rhythm and P-QRS relationship look the same as NSR — the tell is a PR interval that's stretched past 0.20s but stays fixed beat to beat.\",\n },\n ],\n },\n {\n id: \"second-degree-1\",\n name: \"Second-Degree AV Block Type I (Wenckebach)\",\n category: \"AV Block\",\n free: false,\n sortOrder: 12,\n rate: \"Atrial rate normal; ventricular rate slightly slower due to dropped beats\",\n regularity: \"Irregular (patterned — groups of beats with a dropped QRS)\",\n pWave: \"Present, but one eventually isn't followed by a QRS\",\n prInterval: \"Progressively lengthens beat to beat until a QRS is dropped, then resets\",\n qrs: \"Narrow\",\n summary: \"The AV node conduction delay gets progressively worse with each beat until one impulse fails to conduct entirely, dropping a QRS — then the cycle resets and repeats ('longer, longer, longer, drop').\",\n clinicalNote: \"Usually a benign, often reversible pattern (inferior MI, medication effect, high vagal tone) — rarely progresses to complete block, and often just needs monitoring rather than pacing.\",\n waveform: { pattern: \"wenckebach\", rateMin: 60, rateMax: 90, startPrMs: 160, prIncrementMs: 40, cycleBeats: 4 },\n questions: [\n {\n prompt: \"On a strip, the PR interval gets progressively longer over three beats, then a P wave appears with no QRS after it, and the pattern restarts. What is this rhythm?\",\n choices: [\"First-Degree AV Block\", \"Second-Degree AV Block Type I (Wenckebach)\", \"Second-Degree AV Block Type II\", \"Third-Degree AV Block\"],\n correctIndex: 1,\n explanation: \"Progressive PR lengthening culminating in a dropped QRS, then a reset, is the hallmark 'longer, longer, longer, drop' pattern of Wenckebach.\",\n },\n {\n prompt: \"Compared to Type II second-degree block, Wenckebach (Type I) is generally considered:\",\n choices: [\"More dangerous and more likely to progress to complete block\", \"Less dangerous, often benign and reversible\", \"Identical in risk\", \"Only seen in pediatric patients\"],\n correctIndex: 1,\n explanation: \"Type I block is usually at the level of the AV node itself, tends to be transient, and rarely progresses — Type II (below the AV node) carries a higher risk of sudden progression to complete block.\",\n },\n ],\n },\n {\n id: \"second-degree-2\",\n name: \"Second-Degree AV Block Type II\",\n category: \"AV Block\",\n free: false,\n sortOrder: 13,\n rate: \"Atrial rate normal; ventricular rate depends on how many beats drop\",\n regularity: \"Irregular, but PR interval doesn't change beat to beat\",\n pWave: \"Present, with intermittently dropped QRS complexes\",\n prInterval: \"Constant on conducted beats — no progressive lengthening before the drop\",\n qrs: \"Often wide (block is usually below the AV node, in the bundle branches)\",\n summary: \"Unlike Wenckebach, the PR interval stays fixed on every conducted beat — a QRS just suddenly fails to follow a P wave with no warning lengthening beforehand. The block is typically lower in the conduction system.\",\n clinicalNote: \"Higher-risk than Type I — more likely to progress suddenly to complete heart block. Often needs a pacemaker even if currently stable.\",\n waveform: { pattern: \"type2block\", rateMin: 60, rateMax: 90, prMs: 180, dropEvery: 4, wide: true },\n questions: [\n {\n prompt: \"A strip shows a constant PR interval of 0.18s on every conducted beat, but every third P wave has no QRS following it, with no warning lengthening beforehand. What is this rhythm?\",\n choices: [\"Second-Degree AV Block Type I (Wenckebach)\", \"Second-Degree AV Block Type II\", \"First-Degree AV Block\", \"Sinus Arrhythmia\"],\n correctIndex: 1,\n explanation: \"A fixed PR interval with sudden, unpredictable dropped beats (no progressive lengthening) is the defining feature that separates Type II from Wenckebach.\",\n },\n {\n prompt: \"Why is Type II second-degree block generally treated more aggressively than Type I?\",\n choices: [\"It's always asymptomatic\", \"It carries a higher risk of sudden, unpredictable progression to complete heart block\", \"It only occurs in healthy young athletes\", \"It resolves on its own within minutes\"],\n correctIndex: 1,\n explanation: \"Because the block sits below the AV node (in the bundle branches), it's less stable and can progress abruptly and without warning to third-degree block — often prompting pacemaker placement even in stable patients.\",\n },\n ],\n },\n {\n id: \"third-degree\",\n name: \"Third-Degree (Complete) AV Block\",\n category: \"AV Block\",\n free: false,\n sortOrder: 14,\n rate: \"Atrial rate normal; ventricular rate slow (40-60 junctional or <40 ventricular escape)\",\n regularity: \"Both P waves and QRS complexes are regular, but independent of each other\",\n pWave: \"Present, marching out at their own regular rate\",\n prInterval: \"Not measurable — completely variable, no relationship between P and QRS\",\n qrs: \"Narrow (junctional escape) or wide (ventricular escape), depending on where the escape pacemaker sits\",\n summary: \"No atrial impulses reach the ventricles at all — the atria and ventricles are being paced completely independently ('AV dissociation'), with the ventricles relying entirely on a junctional or ventricular escape rhythm to keep beating.\",\n clinicalNote: \"This is a true emergency if the escape rate is too slow to maintain perfusion — transcutaneous pacing and/or a permanent pacemaker are typically needed. Do not give AV-node-blocking drugs.\",\n waveform: { pattern: \"thirdDegree\", atrialRateMin: 70, atrialRateMax: 100, ventricularRateMin: 30, ventricularRateMax: 50, wide: false },\n questions: [\n {\n prompt: \"A strip shows P waves marching out regularly at 90 bpm and QRS complexes marching out regularly at 38 bpm, with no consistent relationship between the two. What is this rhythm?\",\n choices: [\"Second-Degree AV Block Type II\", \"Sinus Arrhythmia\", \"Third-Degree (Complete) AV Block\", \"Atrial Fibrillation\"],\n correctIndex: 2,\n explanation: \"Two independently regular rates — one atrial, one ventricular — with no fixed PR relationship is the signature of complete AV dissociation.\",\n },\n {\n prompt: \"A patient in third-degree AV block with a ventricular rate of 32 and altered mental status needs which immediate intervention?\",\n choices: [\"Adenosine\", \"Vagal maneuvers\", \"Transcutaneous pacing\", \"Observation only\"],\n correctIndex: 2,\n explanation: \"A symptomatic, hemodynamically unstable bradycardia from complete heart block is a pacing emergency — adenosine and vagal maneuvers are for fast rhythms, not slow ones, and observation risks further deterioration.\",\n },\n ],\n },\n {\n id: \"pvc\",\n name: \"Premature Ventricular Contraction (PVC)\",\n category: \"Ventricular\",\n free: true,\n sortOrder: 15,\n rate: \"Underlying rhythm rate, with early wide beats\",\n regularity: \"Irregular (early beat interrupts the pattern)\",\n pWave: \"None associated with the early beat\",\n prInterval: \"Not applicable for the PVC itself\",\n qrs: \"Wide (>0.12s) and bizarre-looking, often followed by a compensatory pause\",\n summary: \"An ectopic focus in the ventricle fires early, bypassing the normal conduction pathway, producing a wide, oddly-shaped QRS with no preceding P wave.\",\n clinicalNote: \"Occasional PVCs are common and often benign. Frequent, multifocal, or PVCs falling on the T wave of the prior beat (R-on-T) raise concern for triggering a lethal rhythm and warrant closer attention.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", baseRateMin: 60, baseRateMax: 90 },\n questions: [\n {\n prompt: \"On an otherwise regular strip, a wide, bizarre-looking QRS appears early with no P wave before it, followed by a pause before the next normal beat. What is this?\",\n choices: [\"Premature Atrial Contraction\", \"Premature Junctional Contraction\", \"Premature Ventricular Contraction\", \"Second-degree AV block\"],\n correctIndex: 2,\n explanation: \"A wide, early QRS with no preceding P wave is the classic PVC picture — the wide complex reflects the impulse spreading through ventricular muscle directly, not the normal fast conduction pathway.\",\n },\n {\n prompt: \"Which finding about a patient's PVCs would be most concerning and worth flagging urgently?\",\n choices: [\"A single isolated PVC once during an 8-hour shift\", \"PVCs from multiple different ventricular sites (multifocal) or landing on the preceding T wave (R-on-T)\", \"A PVC that looks identical to the one seen an hour earlier\", \"PVCs only occurring while the patient is asleep\"],\n correctIndex: 1,\n explanation: \"Multifocal PVCs suggest more irritable ventricular tissue, and R-on-T PVCs can land during the heart's vulnerable repolarization window and trigger V-tach or V-fib — both are higher-risk patterns than an isolated, uniform PVC.\",\n },\n ],\n },\n {\n id: \"idioventricular\",\n name: \"Idioventricular Rhythm\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 16,\n rate: \"20-40 bpm\",\n regularity: \"Regular\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, >0.12s\",\n summary: \"When both the SA node and the AV junction fail to pace, the ventricles fall back on their own intrinsic, very slow escape rate — the pacemaker of last resort.\",\n clinicalNote: \"This rate is rarely enough to sustain adequate perfusion on its own — treat the underlying cause and prepare for pacing; this is often a peri-arrest rhythm.\",\n waveform: { pattern: \"regular\", rateMin: 20, rateMax: 40, hasPWave: false, wide: true },\n questions: [\n {\n prompt: \"A monitor shows a regular, wide-complex rhythm at 28 bpm with no identifiable P waves anywhere on the strip. What is the most likely rhythm?\",\n choices: [\"Junctional Rhythm\", \"Idioventricular Rhythm\", \"Ventricular Tachycardia\", \"Sinus Bradycardia\"],\n correctIndex: 1,\n explanation: \"A wide QRS at a very slow rate (20-40) with no P waves reflects the ventricles pacing themselves as the last-resort intrinsic pacemaker, after higher pacemakers have failed.\",\n },\n {\n prompt: \"Why is idioventricular rhythm considered a high-risk finding even if the patient currently has a pulse?\",\n choices: [\"It always means the patient is already in cardiac arrest\", \"The rate is usually too slow to maintain adequate perfusion and it can deteriorate further without intervention\", \"It's a completely normal variant in healthy adults\", \"It resolves without any treatment needed\"],\n correctIndex: 1,\n explanation: \"20-40 bpm is rarely enough cardiac output to perfuse the brain and organs adequately — it's often seen as a late, unstable rhythm needing urgent treatment of the underlying cause and likely pacing.\",\n },\n ],\n },\n {\n id: \"vtach\",\n name: \"Ventricular Tachycardia (Monomorphic)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 17,\n rate: \">100 bpm, often 150-250\",\n regularity: \"Regular\",\n pWave: \"Absent (or dissociated, unrelated to the QRS)\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, >0.12s, uniform shape from beat to beat ('monomorphic')\",\n summary: \"A run of three or more consecutive PVCs from the same ventricular focus at a fast, regular rate — a wide-complex tachycardia that can rapidly become unstable.\",\n clinicalNote: \"Treatment depends entirely on whether the patient has a pulse and is stable: pulseless V-tach is treated like V-fib (defibrillation, ACLS); stable V-tach with a pulse may get antiarrhythmics; unstable V-tach with a pulse needs synchronized cardioversion.\",\n waveform: { pattern: \"regular\", rateMin: 150, rateMax: 220, hasPWave: false, wide: true },\n questions: [\n {\n prompt: \"A monitor shows a regular, wide-complex rhythm at 180 bpm with a uniform QRS shape on every beat and no visible P waves. The patient has a pulse but is confused and hypotensive. What is this rhythm and the appropriate action?\",\n choices: [\"SVT with aberrancy — give adenosine\", \"Monomorphic V-tach with a pulse, unstable — prepare for synchronized cardioversion\", \"Normal sinus rhythm — no action needed\", \"Atrial fibrillation — start anticoagulation\"],\n correctIndex: 1,\n explanation: \"A fast, wide, regular, uniform rhythm with an unstable patient (altered mental status, hypotension) is unstable V-tach — synchronized cardioversion is indicated, not a rate-control drug.\",\n },\n {\n prompt: \"How is pulseless V-tach managed differently from stable V-tach with a pulse?\",\n choices: [\"Pulseless V-tach is treated exactly like a normal rhythm, no urgency\", \"Pulseless V-tach is treated like V-fib — immediate defibrillation and CPR per ACLS, not synchronized cardioversion\", \"Stable V-tach always requires immediate defibrillation\", \"There is no difference in management\"],\n correctIndex: 1,\n explanation: \"No pulse means no organized output regardless of what the monitor shows — pulseless V-tach is a cardiac arrest rhythm managed with immediate defibrillation and CPR, the same as V-fib.\",\n },\n ],\n },\n {\n id: \"torsades\",\n name: \"Torsades de Pointes\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 18,\n rate: \"150-250 bpm\",\n regularity: \"Irregular\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, with amplitude that twists around the baseline ('twisting of the points')\",\n summary: \"A distinctive polymorphic V-tach where the QRS complexes appear to spiral or twist around the isoelectric baseline — classically associated with a prolonged QT interval on the preceding baseline rhythm.\",\n clinicalNote: \"Magnesium sulfate is first-line treatment, unlike standard V-tach. Also review and stop any QT-prolonging medications contributing to the underlying cause.\",\n waveform: { pattern: \"torsades\", rateMin: 150, rateMax: 220 },\n questions: [\n {\n prompt: \"A wide-complex tachycardia shows QRS complexes that appear to twist in amplitude around the baseline, changing shape continuously rather than staying uniform. What is this rhythm?\",\n choices: [\"Monomorphic Ventricular Tachycardia\", \"Torsades de Pointes\", \"Ventricular Fibrillation\", \"Atrial Flutter\"],\n correctIndex: 1,\n explanation: \"The twisting, varying QRS amplitude (as opposed to monomorphic V-tach's uniform shape) is the defining visual feature that gives torsades its name.\",\n },\n {\n prompt: \"What is the first-line treatment for torsades de pointes, distinct from standard V-tach management?\",\n choices: [\"Amiodarone\", \"Magnesium sulfate\", \"Atropine\", \"Adenosine\"],\n correctIndex: 1,\n explanation: \"Torsades is strongly linked to a prolonged QT interval, and IV magnesium is first-line — it stabilizes the cardiac membrane even when magnesium levels are normal.\",\n },\n ],\n },\n {\n id: \"vfib\",\n name: \"Ventricular Fibrillation\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 19,\n rate: \"Not organized — no true rate\",\n regularity: \"Chaotic, no pattern\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"No identifiable QRS complexes — chaotic, disorganized waveform\",\n summary: \"Multiple ventricular sites fire chaotically and simultaneously, so the ventricles quiver instead of contracting — there is no organized electrical activity and no cardiac output whatsoever.\",\n clinicalNote: \"This is cardiac arrest. Immediate CPR and defibrillation are the only effective interventions — there is no pulse to check for or medication that substitutes for defibrillation.\",\n waveform: { pattern: \"chaotic\" },\n questions: [\n {\n prompt: \"A monitor shows a completely chaotic waveform with no identifiable P waves, QRS complexes, or any repeating pattern. The patient is unresponsive with no pulse. What is this rhythm and the immediate action?\",\n choices: [\"Asystole — begin transcutaneous pacing\", \"Ventricular Fibrillation — begin CPR and defibrillate immediately\", \"Sinus Arrhythmia — reassess in 5 minutes\", \"Atrial Fibrillation — control the rate with a beta blocker\"],\n correctIndex: 1,\n explanation: \"A chaotic, disorganized waveform with no pulse is V-fib — immediate CPR and defibrillation are the only interventions that restore organized electrical activity.\",\n },\n {\n prompt: \"Why does V-fib produce no pulse even though there's electrical activity on the monitor?\",\n choices: [\"The rate is simply too slow to generate a pulse\", \"The ventricles are quivering chaotically instead of contracting in a coordinated way, so no blood is being pumped\", \"The electrical activity is too fast to register a pulse manually\", \"V-fib patients always retain a weak pulse\"],\n correctIndex: 1,\n explanation: \"Effective pumping requires coordinated contraction — chaotic, disorganized electrical activity produces quivering muscle, not a mechanical pump stroke, so there's electrical activity but zero cardiac output.\",\n },\n ],\n },\n {\n id: \"asystole\",\n name: \"Asystole\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 20,\n rate: \"None\",\n regularity: \"Not applicable — flatline\",\n pWave: \"Absent (occasional P waves alone with no QRS can occur — 'P-wave asystole')\",\n prInterval: \"Not applicable\",\n qrs: \"None — no electrical activity\",\n summary: \"Complete absence of ventricular electrical activity — a flatline. Always confirm in more than one lead and check that leads are actually attached before treating as true asystole (a loose lead can mimic it).\",\n clinicalNote: \"Not a shockable rhythm — defibrillation does nothing for a flatline. Management is high-quality CPR, epinephrine, and searching for and treating a reversible cause (the H's and T's).\",\n waveform: { pattern: \"flatline\" },\n questions: [\n {\n prompt: \"A monitor shows a flat line with no electrical activity in any lead, confirmed with leads properly attached. The patient is unresponsive with no pulse. What is the appropriate immediate treatment?\",\n choices: [\"Immediate defibrillation\", \"High-quality CPR and epinephrine, while searching for a reversible cause — this is not a shockable rhythm\", \"Synchronized cardioversion\", \"Adenosine\"],\n correctIndex: 1,\n explanation: \"Asystole has no organized electrical activity for a shock to organize — defibrillating a flatline does nothing. CPR, epinephrine, and finding a reversible cause are the actual interventions.\",\n },\n {\n prompt: \"Before treating a flatline on the monitor as true asystole, what should always be checked first?\",\n choices: [\"The patient's blood pressure\", \"That the leads are properly attached and the rhythm is confirmed in more than one lead\", \"The patient's temperature\", \"The time of day\"],\n correctIndex: 1,\n explanation: \"A disconnected or loose lead can produce a flatline that looks exactly like asystole — always rule out an equipment/lead problem before committing to that diagnosis.\",\n },\n ],\n },\n {\n id: \"sinus-arrhythmia\",\n name: \"Sinus Arrhythmia\",\n category: \"Sinus\",\n free: false,\n sortOrder: 21,\n rate: \"60-100 bpm\",\n regularity: \"Irregular — rate cycles with breathing\",\n pWave: \"Present, upright, one before every QRS, normal shape\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"Vagal tone rises and falls with breathing, so the SA node speeds up on inspiration and slows on expiration even though it's still fully in charge of pacing.\",\n clinicalNote: \"A normal physiologic finding, especially in younger or athletic patients — no treatment needed. Non-respiratory variation in an older patient can be a clue to sinus node disease.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: true, wide: false, prMs: 160, irregular: true },\n questions: [\n {\n prompt: \"A strip shows a normal P wave before every narrow QRS and a constant PR interval, but the R-R interval visibly speeds up and slows down in a repeating pattern. What is this rhythm?\",\n choices: [\"Atrial Fibrillation\", \"Sinus Arrhythmia\", \"Second-Degree AV Block Type I\", \"Multifocal Atrial Tachycardia\"],\n correctIndex: 1,\n explanation: \"Sinus arrhythmia keeps a normal, unchanging P-QRS relationship — only the rate drifts, cycling with the respiratory pattern, unlike the chaotic irregularity of afib or MAT.\",\n },\n {\n prompt: \"What causes the cyclic rate change seen in sinus arrhythmia?\",\n choices: [\"A second competing pacemaker in the atria\", \"Vagal tone shifting with the breathing cycle, speeding the SA node on inspiration and slowing it on expiration\", \"Intermittent failure of the AV node to conduct\", \"Digoxin toxicity\"],\n correctIndex: 1,\n explanation: \"It's a normal autonomic effect — breathing modulates vagal tone, and the SA node responds by speeding up and slowing down in step with it.\",\n },\n ],\n },\n {\n id: \"sinus-pause\",\n name: \"Sinus Arrest / Sinus Pause\",\n category: \"Sinus\",\n free: false,\n sortOrder: 22,\n rate: \"Normal until the pause; escape rate depends on which pacemaker takes over\",\n regularity: \"Regular, interrupted by a pause that isn't a clean multiple of the normal P-P interval\",\n pWave: \"Normal in sinus beats; absent during the pause\",\n prInterval: \"Normal in sinus beats\",\n qrs: \"Narrow, unless a ventricular escape beat ends the pause\",\n summary: \"The SA node simply fails to fire for a beat or more. A gap under 2 seconds is called a pause; 2 seconds or longer is called an arrest — a lower pacemaker usually escapes to keep the heart beating.\",\n clinicalNote: \"Often vagally mediated and benign in a healthy young patient, but can reflect sick sinus syndrome, drug effect (beta-blockers, calcium channel blockers, digoxin), or ischemia. A long pause causing syncope is called an Adams-Stokes attack.\",\n waveform: { pattern: \"pause\", rateMin: 60, rateMax: 90, hasPWave: true, prMs: 160 },\n questions: [\n {\n prompt: \"An otherwise regular strip shows one unexpectedly long gap with no P wave or QRS, not matching any clean multiple of the normal beat-to-beat interval, before the rhythm resumes. What does this describe?\",\n choices: [\"Second-Degree AV Block Type II\", \"Sinus Arrest / Sinus Pause\", \"Atrial Flutter\", \"Third-Degree AV Block\"],\n correctIndex: 1,\n explanation: \"The SA node briefly fails to fire, producing a pause with no P wave at all — different from a block, where a P wave is present but simply fails to conduct.\",\n },\n {\n prompt: \"What is the key difference between a 'sinus pause' and 'sinus arrest'?\",\n choices: [\"Pauses only happen in children\", \"Arrest always requires a pacemaker; pauses never do\", \"They're defined by duration — a pause is under 2 seconds, arrest is 2 seconds or longer\", \"There is no real difference\"],\n correctIndex: 2,\n explanation: \"Both describe the same SA node failure — the terms just split by how long the gap lasts.\",\n },\n ],\n },\n {\n id: \"wap\",\n name: \"Wandering Atrial Pacemaker (WAP)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 23,\n rate: \"<100 bpm\",\n regularity: \"Irregularly irregular\",\n pWave: \"At least 3 distinct P-wave shapes in the same view, varying beat to beat\",\n prInterval: \"Varies beat to beat along with the P wave\",\n qrs: \"Narrow\",\n summary: \"Pacemaker control shifts back and forth among the SA node, atrial tissue, and the AV junction, so each beat's P wave looks a little different depending on where it started.\",\n clinicalNote: \"Usually a benign, often incidental finding in young athletes or older adults with pulmonary disease — no treatment needed unless symptomatic.\",\n waveform: { pattern: \"multifocal\", rateMin: 60, rateMax: 95 },\n questions: [\n {\n prompt: \"A strip under 100 bpm shows P waves that change shape and size from beat to beat — at least three distinct forms — with a correspondingly variable PR interval. What is this rhythm?\",\n choices: [\"Multifocal Atrial Tachycardia\", \"Wandering Atrial Pacemaker\", \"Atrial Fibrillation\", \"Premature Atrial Contractions\"],\n correctIndex: 1,\n explanation: \"Multiple shifting P-wave shapes under 100 bpm is WAP — the same pattern above 100 bpm is called MAT instead.\",\n },\n {\n prompt: \"What's the practical difference between Wandering Atrial Pacemaker and Multifocal Atrial Tachycardia?\",\n choices: [\"WAP has a wide QRS and MAT doesn't\", \"They're the same underlying pattern, split purely by rate — under 100 bpm is WAP, over 100 bpm is MAT\", \"WAP only occurs in infants\", \"MAT always has a single P-wave shape\"],\n correctIndex: 1,\n explanation: \"Both show the same shifting-pacemaker P-wave pattern; the rate cutoff of 100 bpm is the only thing that separates the two names.\",\n },\n ],\n },\n {\n id: \"mat\",\n name: \"Multifocal Atrial Tachycardia (MAT)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 24,\n rate: \"Usually 100-150 bpm, occasionally faster\",\n regularity: \"Irregularly irregular\",\n pWave: \"At least 3 distinct P-wave shapes in the same view\",\n prInterval: \"Variable; some P waves may not conduct\",\n qrs: \"Usually narrow\",\n summary: \"Multiple irritable atrial foci compete to pace the heart, each firing on its own, so no single organized P-wave pattern or rate emerges — often driven by hypoxia, a catecholamine surge, or an electrolyte disturbance.\",\n clinicalNote: \"Classically seen with a COPD exacerbation or decompensated heart failure — it's a marker of how sick the underlying illness is. Treat the underlying cause rather than the rhythm; AV nodal agents are used cautiously, and digoxin or cardioversion generally don't work.\",\n waveform: { pattern: \"multifocal\", rateMin: 100, rateMax: 150, irregular: true },\n questions: [\n {\n prompt: \"A COPD patient's monitor shows a chaotic rhythm at 130 bpm with at least three different P-wave shapes and a variable PR interval. What is this rhythm, and what should you focus treatment on?\",\n choices: [\"Atrial Flutter — synchronized cardioversion\", \"Multifocal Atrial Tachycardia — treat the underlying hypoxia/illness, not the rhythm directly\", \"Sinus Tachycardia — reassurance only\", \"SVT — adenosine\"],\n correctIndex: 1,\n explanation: \"MAT is a marker of underlying illness (classically COPD or heart failure) — cardioversion and digoxin generally don't work, and the priority is treating what's driving it.\",\n },\n {\n prompt: \"MAT and Wandering Atrial Pacemaker share the same multi-shaped P-wave pattern. What distinguishes MAT?\",\n choices: [\"A wide QRS\", \"A rate over 100 bpm\", \"The complete absence of P waves\", \"A fixed, unchanging PR interval\"],\n correctIndex: 1,\n explanation: \"The underlying mechanism — multiple competing atrial foci — is identical; MAT is simply the name used once the rate crosses 100 bpm.\",\n },\n ],\n },\n {\n id: \"junctional-tach\",\n name: \"Junctional Tachycardia\",\n category: \"Junctional\",\n free: false,\n sortOrder: 25,\n rate: \">100 bpm\",\n regularity: \"Regular\",\n pWave: \"Retrograde (inverted) if visible — may fall before, within, or after the QRS\",\n prInterval: \"Short (<0.12s) if a P wave precedes the QRS; often unmeasurable\",\n qrs: \"Narrow, unless a pre-existing bundle branch block is present\",\n summary: \"The AV junction fires faster than the SA node and takes over as pacemaker, sending impulses down to the ventricles normally but backward into the atria — producing the inverted P waves when they're visible at all.\",\n clinicalNote: \"Classically associated with digoxin toxicity; also seen with ischemia, myocarditis, or after cardiac surgery. Typically doesn't respond to vagal maneuvers, which helps distinguish it from a re-entrant SVT.\",\n waveform: { pattern: \"regular\", rateMin: 100, rateMax: 160, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A monitor shows a regular, narrow-complex rhythm at 120 bpm with no clearly visible P waves, unresponsive to vagal maneuvers. Which cause should specifically come to mind?\",\n choices: [\"Caffeine intake\", \"Digoxin toxicity\", \"Athletic conditioning\", \"Dehydration\"],\n correctIndex: 1,\n explanation: \"Junctional tachycardia is a classic digoxin toxicity finding — it's also one of the clues that helps separate it from a re-entrant SVT, which usually does respond to vagal maneuvers.\",\n },\n {\n prompt: \"Why are P waves inverted (retrograde) in junctional tachycardia when they're visible at all?\",\n choices: [\"The SA node is firing backward\", \"The AV junction paces the ventricles normally but conducts backward up into the atria\", \"The atria are fibrillating\", \"The QRS is masking a normal upright P wave\"],\n correctIndex: 1,\n explanation: \"The junction sits between the atria and ventricles — when it takes over pacing, the impulse still reaches the ventricles normally but has to travel backward to reach the atria, producing an inverted P wave.\",\n },\n ],\n },\n {\n id: \"aivr\",\n name: \"Accelerated Idioventricular Rhythm (AIVR)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 26,\n rate: \"40-100 bpm (some sources extend to 110-120)\",\n regularity: \"Regular\",\n pWave: \"Often dissociated from the QRS; occasional fusion/capture beats\",\n prInterval: \"Not applicable (P and QRS are dissociated) except at fusion beats\",\n qrs: \"Wide, bizarre, ventricular in origin\",\n summary: \"An irritable focus in the ventricle fires slightly faster than the SA node and briefly takes over pacing — 'accelerated' because it's faster than a normal ventricular escape rhythm (20-40) but not fast enough to call it V-tach.\",\n clinicalNote: \"A classic, usually benign finding after reperfusion (post-thrombolysis or PCI in a STEMI) — a 'reperfusion arrhythmia.' It's typically self-limited; treating it with antiarrhythmics is generally avoided since it can suppress the only functioning ventricular rhythm.\",\n waveform: { pattern: \"regular\", rateMin: 40, rateMax: 100, hasPWave: false, wide: true },\n questions: [\n {\n prompt: \"Shortly after a patient receives reperfusion therapy for a STEMI, the monitor shows a regular, wide-complex rhythm at 75 bpm. What is the most likely rhythm, and the appropriate response?\",\n choices: [\"Ventricular Tachycardia — synchronized cardioversion\", \"Accelerated Idioventricular Rhythm — usually benign, generally just observe\", \"Third-Degree AV Block — transcutaneous pacing\", \"Asystole — begin CPR\"],\n correctIndex: 1,\n explanation: \"AIVR classically shows up right after reperfusion and is usually a benign, self-limited finding — treating it aggressively can actually suppress the ventricular rhythm keeping the patient perfused.\",\n },\n {\n prompt: \"What separates AIVR from a slow Ventricular Tachycardia?\",\n choices: [\"AIVR always has a narrow QRS\", \"Rate is the main distinguishing feature, though the two can overlap — AIVR is generally under 100-120 bpm\", \"AIVR only occurs in children\", \"V-tach never has AV dissociation\"],\n correctIndex: 1,\n explanation: \"Both are wide-complex ventricular rhythms — rate is the main practical distinguishing feature, though sources acknowledge some overlap at the upper end of AIVR's range.\",\n },\n ],\n },\n {\n id: \"v-paced\",\n name: \"Ventricular Paced Rhythm\",\n category: \"Other\",\n free: false,\n sortOrder: 27,\n rate: \"Set by the pacemaker's programmed rate (commonly ~60-70 bpm baseline)\",\n regularity: \"Regular\",\n pWave: \"Absent or dissociated — a single-chamber ventricular pacemaker doesn't sense or pace the atrium\",\n prInterval: \"Not applicable for paced beats\",\n qrs: \"Wide, preceded by a sharp pacing spike; often resembles a left bundle branch block pattern\",\n summary: \"A wire in the right ventricle delivers an electrical stimulus directly to the heart muscle whenever the intrinsic rate drops below the device's set threshold, producing a wide, bizarre QRS with a pacing spike right before it.\",\n clinicalNote: \"This is the expected, normal appearance for a functioning single-chamber ventricular pacemaker. Standard STEMI criteria don't apply to paced beats — watch instead for failure to capture (a spike with no QRS following it) or failure to sense.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 72, hasPWave: false, wide: true, pacedSpike: true },\n questions: [\n {\n prompt: \"A strip shows a sharp vertical spike immediately before every wide, bizarre QRS, at a fixed rate of 70 bpm. What does this represent?\",\n choices: [\"Wolff-Parkinson-White pattern\", \"A functioning ventricular paced rhythm\", \"Torsades de Pointes\", \"First-Degree AV Block\"],\n correctIndex: 1,\n explanation: \"The pacing spike right before a wide QRS is the signature of a ventricular pacemaker firing — the device is generating the beat directly rather than the heart's own conduction system.\",\n },\n {\n prompt: \"A pacing spike appears on the strip but is NOT followed by a QRS complex. What does this indicate?\",\n choices: [\"Normal pacemaker function\", \"Failure to capture — the pacing stimulus isn't triggering a ventricular contraction\", \"Sinus arrhythmia\", \"First-degree AV block\"],\n correctIndex: 1,\n explanation: \"A spike with no resulting QRS means the electrical stimulus reached the tissue but failed to depolarize it — a pacemaker malfunction called failure to capture, worth flagging urgently.\",\n },\n ],\n },\n {\n id: \"wpw\",\n name: \"Wolff-Parkinson-White (WPW) Pattern\",\n category: \"Other\",\n free: false,\n sortOrder: 28,\n rate: \"Normal at baseline (WPW is a conduction pattern, not itself a tachycardia)\",\n regularity: \"Regular at baseline\",\n pWave: \"Normal sinus P wave\",\n prInterval: \"Short, <0.12s\",\n qrs: \"Wide, >0.12s, with a slurred, slowed initial upstroke (the 'delta wave')\",\n summary: \"An extra electrical connection between atria and ventricles (an accessory pathway) bypasses the AV node's normal delay, so part of the ventricle is activated early — producing the short PR interval and the slurred delta-wave upstroke where the early and normal wavefronts fuse.\",\n clinicalNote: \"Predisposes to re-entrant tachycardias and, critically, to very rapid ventricular rates if the patient develops atrial fibrillation, since the accessory pathway lacks the AV node's rate-limiting property. AV-node-blocking drugs (adenosine, beta-blockers, calcium channel blockers, digoxin) are contraindicated in pre-excited afib because they can paradoxically speed conduction down the bypass tract.\",\n waveform: { pattern: \"regular\", rateMin: 65, rateMax: 90, hasPWave: true, wide: true, prMs: 90, delta: true },\n questions: [\n {\n prompt: \"A resting strip shows a short PR interval and a QRS with a slurred, slowed initial upstroke before the sharp spike. What does this describe?\",\n choices: [\"First-Degree AV Block\", \"Wolff-Parkinson-White (WPW) pattern\", \"Right bundle branch block\", \"Sinus Tachycardia\"],\n correctIndex: 1,\n explanation: \"A short PR interval plus a delta wave — that slurred upstroke — is the defining ECG signature of pre-excitation from an accessory pathway.\",\n },\n {\n prompt: \"Why are adenosine, beta-blockers, and calcium channel blockers dangerous in a WPW patient who develops atrial fibrillation?\",\n choices: [\"They have no effect on the accessory pathway either way\", \"They slow the AV node, which can paradoxically push more of the fast atrial activity down the unprotected accessory pathway to the ventricles\", \"They only work in adults over 65\", \"They cure the accessory pathway permanently\"],\n correctIndex: 1,\n explanation: \"Unlike the AV node, the accessory pathway has no built-in rate limiter — blocking the AV node removes the 'safety valve' and can let dangerously fast atrial rates conduct straight to the ventricles, risking V-fib.\",\n },\n ],\n },\n];\n","// Standard nursing/EMS EKG curriculum — 20 core rhythms.\n// free: true rhythms are visible without a Pro unlock.\nexport interface Question {\n prompt: string;\n choices: string[];\n correctIndex: number;\n explanation: string;\n}\n\n// Machine-readable description of what a rhythm strip looks like, used by\n// frontend/lib/waveform.ts to synthesize a fresh, slightly-randomized strip\n// on every practice round (not a literal clinical tracing — a teaching\n// approximation of rate, regularity, P-wave presence, and QRS width/shape).\nexport type WaveformPattern =\n | \"regular\"\n | \"ectopic\"\n | \"patternedEctopy\"\n | \"burstEctopy\"\n | \"parasystole\"\n | \"tachyBrady\"\n | \"failToCapture\"\n | \"failToSense\"\n | \"idioventricularCapture\"\n | \"afib\"\n | \"aflutter\"\n | \"wenckebach\"\n | \"type2block\"\n | \"thirdDegree\"\n | \"torsades\"\n | \"chaotic\"\n | \"flatline\"\n | \"pause\"\n | \"multifocal\";\n\nexport interface WaveformSpec {\n pattern: WaveformPattern;\n rateMin?: number;\n rateMax?: number;\n hasPWave?: boolean;\n wide?: boolean;\n prMs?: number;\n ectopicSubtype?: \"atrial\" | \"junctional\" | \"ventricular\";\n baseRateMin?: number;\n baseRateMax?: number;\n atrialRate?: number;\n ratios?: number[];\n startPrMs?: number;\n prIncrementMs?: number;\n cycleBeats?: number;\n dropEvery?: number;\n atrialRateMin?: number;\n atrialRateMax?: number;\n ventricularRateMin?: number;\n ventricularRateMax?: number;\n irregular?: boolean;\n delta?: boolean;\n pacedSpike?: boolean;\n // Extended fields for the expanded (100+) library — patterned/burst ectopy,\n // electrolyte/drug/device effects, and simple visual modifiers reused by\n // the 12-lead grid. All are optional teaching approximations, not literal\n // clinical tracings.\n count?: number; // how many ectopic beats to insert (unifocal/multifocal PVCs)\n unit?: number; // patternedEctopy: 2 = bigeminy, 3 = trigeminy\n burstLength?: number; // burstEctopy: couplet=2, triplet/NSVT=3+\n burstRateMin?: number;\n burstRateMax?: number;\n qDeep?: boolean; // exaggerated pathologic Q wave\n tAmpScale?: number; // T-wave amplitude multiplier (peaked/flattened T)\n tInvert?: boolean; // flip T-wave polarity\n qtOffsetMs?: number; // shift T-wave center (long/short QT)\n uWave?: boolean; // add a small U wave after the T\n stScoop?: boolean; // digoxin-effect ST sag\n stElevation?: boolean; // ST elevation bump\n stDepression?: boolean; // ST depression dip\n osbornWave?: boolean; // hypothermia J wave\n ampScale?: number; // global amplitude multiplier (low voltage)\n alternans?: boolean; // alternating beat-to-beat amplitude\n interference?: boolean; // fine AC-interference overlay\n}\n\nexport interface Rhythm {\n id: string;\n name: string;\n category: \"Sinus\" | \"Atrial\" | \"Junctional\" | \"AV Block\" | \"Ventricular\" | \"Other\";\n free: boolean;\n sortOrder: number;\n rate: string;\n regularity: string;\n pWave: string;\n prInterval: string;\n qrs: string;\n summary: string;\n clinicalNote: string;\n waveform: WaveformSpec;\n questions: Question[];\n}\n\nexport const RHYTHMS: Rhythm[] = [\n {\n id: \"nsr\",\n name: \"Normal Sinus Rhythm\",\n category: \"Sinus\",\n free: true,\n sortOrder: 1,\n rate: \"60-100 bpm\",\n regularity: \"Regular\",\n pWave: \"Present, upright, one before every QRS\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"The baseline rhythm every other rhythm is compared against — originates in the SA node, conducts normally through the AV node.\",\n clinicalNote: \"No intervention needed. This is the rhythm you're confirming is present, not absent, before worrying about anything else on the strip.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: true, wide: false, prMs: 160 },\n questions: [\n {\n prompt: \"A patient's monitor shows a rate of 78, regular, with an upright P wave before every QRS and a PR interval of 0.16s. What is this rhythm?\",\n choices: [\"Normal Sinus Rhythm\", \"Sinus Tachycardia\", \"First-Degree AV Block\", \"Junctional Rhythm\"],\n correctIndex: 0,\n explanation: \"Rate 60-100, regular, P before every QRS, normal PR interval — textbook NSR.\",\n },\n {\n prompt: \"Which feature, if it were missing, would rule OUT normal sinus rhythm?\",\n choices: [\"A narrow QRS\", \"An upright P wave before every QRS\", \"A rate under 150\", \"A regular rhythm\"],\n correctIndex: 1,\n explanation: \"Sinus rhythms are defined by the P wave originating from the SA node and preceding every QRS — lose that relationship and it's no longer sinus.\",\n },\n ],\n },\n {\n id: \"sinus-brady\",\n name: \"Sinus Bradycardia\",\n category: \"Sinus\",\n free: true,\n sortOrder: 2,\n rate: \"<60 bpm\",\n regularity: \"Regular\",\n pWave: \"Present, upright, one before every QRS\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"Same conduction pattern as NSR, just slower than 60. Can be normal (athletes, sleep) or pathologic (meds, sick sinus syndrome, hypothyroidism).\",\n clinicalNote: \"Only treat if symptomatic (hypotension, altered mental status, chest pain) — a healthy resting rate of 48 in a fit patient needs no intervention.\",\n waveform: { pattern: \"regular\", rateMin: 40, rateMax: 59, hasPWave: true, wide: false, prMs: 160 },\n questions: [\n {\n prompt: \"A rhythm strip shows a rate of 44, regular, normal P waves and PR interval, narrow QRS. The patient is alert, talking, and has a normal blood pressure. What's the priority action?\",\n choices: [\"Give atropine immediately\", \"Start transcutaneous pacing\", \"Monitor — this may not require treatment if asymptomatic\", \"Perform synchronized cardioversion\"],\n correctIndex: 2,\n explanation: \"Sinus bradycardia is only treated when it's causing symptoms. An asymptomatic, hemodynamically stable patient just gets monitored.\",\n },\n {\n prompt: \"Which of these is a common non-pathologic cause of sinus bradycardia?\",\n choices: [\"Third-degree AV block\", \"High level of physical conditioning (athlete's heart)\", \"Digoxin toxicity\", \"Hyperthyroidism\"],\n correctIndex: 1,\n explanation: \"Well-conditioned athletes often have resting rates in the 40s-50s from high vagal tone and stroke volume — a normal finding, not a block.\",\n },\n ],\n },\n {\n id: \"sinus-tach\",\n name: \"Sinus Tachycardia\",\n category: \"Sinus\",\n free: true,\n sortOrder: 3,\n rate: \">100 bpm\",\n regularity: \"Regular\",\n pWave: \"Present, upright, one before every QRS\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"Normal conduction, just faster than 100 — almost always a response to something else (pain, fever, dehydration, anxiety, blood loss), not a primary cardiac problem.\",\n clinicalNote: \"Treat the cause, not the rate — find and fix why the heart is compensating (fluids for dehydration, pain control, treat the fever) rather than trying to slow it directly.\",\n waveform: { pattern: \"regular\", rateMin: 101, rateMax: 150, hasPWave: true, wide: false, prMs: 140 },\n questions: [\n {\n prompt: \"A trauma patient's monitor shows a regular rhythm at 128 bpm with normal P waves and narrow QRS. What should you look for first?\",\n choices: [\"A drug that blocks the AV node\", \"A source of blood loss, pain, or hypoxia driving the rate up\", \"Evidence of a missed P wave\", \"A prolonged QT interval\"],\n correctIndex: 1,\n explanation: \"Sinus tach is almost always secondary to something — in trauma, think hemorrhage first. Slowing the rate directly (e.g. a beta blocker) without fixing the cause can be dangerous.\",\n },\n {\n prompt: \"What distinguishes sinus tachycardia from SVT on a monitor?\",\n choices: [\"Sinus tach has no visible P waves\", \"Sinus tach rarely exceeds 220 bpm and P waves are visible before each QRS\", \"Sinus tach always requires adenosine\", \"Sinus tach has a wide QRS\"],\n correctIndex: 1,\n explanation: \"Sinus tach retains normal P waves and typically tops out lower than SVT, which is often faster and can obscure or hide the P wave in the preceding T wave.\",\n },\n ],\n },\n {\n id: \"pac\",\n name: \"Premature Atrial Contraction (PAC)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 4,\n rate: \"Underlying rhythm rate, with early beats\",\n regularity: \"Irregular (early beat interrupts the pattern)\",\n pWave: \"Early, and often a different shape than the sinus P wave\",\n prInterval: \"May be shorter or longer than normal\",\n qrs: \"Usually narrow (unless aberrantly conducted)\",\n summary: \"An ectopic focus in the atria fires before the SA node's next scheduled beat, causing an early beat with an abnormal-looking P wave.\",\n clinicalNote: \"Usually benign — caffeine, stress, and stimulants are common triggers. Frequent PACs can sometimes signal developing atrial fibrillation.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"atrial\", baseRateMin: 60, baseRateMax: 90 },\n questions: [\n {\n prompt: \"On an otherwise regular strip, one beat arrives early with a P wave that looks different from the others, followed by a normal QRS. What is this?\",\n choices: [\"Premature Ventricular Contraction\", \"Premature Atrial Contraction\", \"Second-degree AV block\", \"Atrial flutter\"],\n correctIndex: 1,\n explanation: \"An early beat with an abnormally-shaped (but present) P wave and a normal QRS is the signature of a PAC — the ectopic focus is atrial, not ventricular.\",\n },\n {\n prompt: \"A patient asks if their occasional PACs, found on a routine monitor, are dangerous. What's the most accurate response?\",\n choices: [\"They always require immediate cardioversion\", \"They're usually benign, often triggered by caffeine or stress, though frequent PACs are worth monitoring\", \"They mean the patient is in cardiac arrest\", \"They can only be caused by a heart attack\"],\n correctIndex: 1,\n explanation: \"Occasional PACs are common and usually harmless. It's a pattern of frequent PACs, not an isolated one, that occasionally warrants a closer look for developing afib.\",\n },\n ],\n },\n {\n id: \"afib\",\n name: \"Atrial Fibrillation\",\n category: \"Atrial\",\n free: true,\n sortOrder: 5,\n rate: \"Variable (ventricular response can be slow, controlled, or rapid)\",\n regularity: \"Irregularly irregular\",\n pWave: \"Absent — replaced by chaotic fibrillatory waves\",\n prInterval: \"Not measurable (no discrete P wave)\",\n qrs: \"Usually narrow\",\n summary: \"Multiple chaotic atrial foci fire simultaneously instead of one coordinated SA node signal, so the atria quiver rather than contract, and the ventricles respond irregularly.\",\n clinicalNote: \"The classic teaching point is 'irregularly irregular' with no true P waves. Stroke risk from atrial clot formation is the major long-term concern, not just the rhythm itself.\",\n waveform: { pattern: \"afib\", rateMin: 70, rateMax: 150 },\n questions: [\n {\n prompt: \"A strip shows no identifiable P waves, a chaotic baseline, and an R-R interval that varies with no repeating pattern. What is this rhythm?\",\n choices: [\"Sinus Arrhythmia\", \"Atrial Flutter\", \"Atrial Fibrillation\", \"Third-degree AV block\"],\n correctIndex: 2,\n explanation: \"Absent P waves plus an irregularly irregular rhythm (no predictable pattern at all, unlike flutter's often-regular ratios) is the defining picture of afib.\",\n },\n {\n prompt: \"Why is atrial fibrillation clinically significant beyond the rhythm itself?\",\n choices: [\"It always causes immediate cardiac arrest\", \"The quivering atria don't empty fully, raising the risk of clot formation and stroke\", \"It permanently damages the AV node\", \"It cannot occur in otherwise healthy people\"],\n correctIndex: 1,\n explanation: \"Blood pooling in the poorly-contracting atria can clot; if that clot embolizes, it can cause a stroke — this is why anticoagulation is a major part of afib management.\",\n },\n ],\n },\n {\n id: \"aflutter\",\n name: \"Atrial Flutter\",\n category: \"Atrial\",\n free: false,\n sortOrder: 6,\n rate: \"Atrial rate ~250-350 bpm; ventricular rate depends on conduction ratio\",\n regularity: \"Often regular (fixed conduction ratio) but can be irregular (variable conduction)\",\n pWave: \"Sawtooth ('flutter') waves, no isoelectric baseline\",\n prInterval: \"Not measurable in the usual sense\",\n qrs: \"Usually narrow\",\n summary: \"A single reentrant circuit in the atria fires very rapidly and regularly, producing the classic sawtooth pattern; the AV node protects the ventricles by only conducting a fraction of those impulses through (commonly 2:1, 3:1, or 4:1).\",\n clinicalNote: \"Look for the sawtooth pattern, most visible in leads II, III, and aVF — a 2:1 conduction ratio can be easy to mistake for sinus tach if you don't count carefully.\",\n waveform: { pattern: \"aflutter\", atrialRate: 300, ratios: [2, 3, 4] },\n questions: [\n {\n prompt: \"A strip shows a sawtooth-shaped baseline at roughly 300 bpm with every other flutter wave conducting to the ventricles, giving a ventricular rate near 150. What is this rhythm?\",\n choices: [\"Atrial Fibrillation\", \"Atrial Flutter with 2:1 conduction\", \"Sinus Tachycardia\", \"Ventricular Tachycardia\"],\n correctIndex: 1,\n explanation: \"The sawtooth pattern at ~300 with a 2:1 AV conduction ratio (every other impulse getting through) producing a ventricular rate near 150 is the classic atrial flutter picture.\",\n },\n {\n prompt: \"What structure is responsible for protecting the ventricles from the very fast atrial rate in atrial flutter?\",\n choices: [\"The SA node\", \"The AV node, by not conducting every atrial impulse through\", \"The bundle of His\", \"The Purkinje fibers\"],\n correctIndex: 1,\n explanation: \"The AV node's refractory period limits how many of the rapid atrial impulses actually reach the ventricles — that's why the ventricular rate is a fraction of the atrial rate.\",\n },\n ],\n },\n {\n id: \"svt\",\n name: \"Supraventricular Tachycardia (SVT)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 7,\n rate: \"150-250 bpm\",\n regularity: \"Regular\",\n pWave: \"Often hidden in the preceding T wave or not visible\",\n prInterval: \"Not measurable if P waves aren't visible\",\n qrs: \"Narrow (unless aberrantly conducted)\",\n summary: \"An umbrella term for fast, regular rhythms originating above the ventricles, most commonly from a reentrant circuit involving the AV node — starts and stops abruptly.\",\n clinicalNote: \"Vagal maneuvers (bearing down, carotid massage by a trained provider) or adenosine are first-line treatments — both work by transiently blocking the AV node to interrupt the reentrant circuit.\",\n waveform: { pattern: \"regular\", rateMin: 150, rateMax: 220, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A patient reports their heart 'suddenly took off' and the monitor shows a narrow-complex rhythm at 180 bpm, perfectly regular, with no visible P waves. What is the most likely rhythm?\",\n choices: [\"Sinus Tachycardia\", \"Supraventricular Tachycardia (SVT)\", \"Ventricular Tachycardia\", \"Atrial Flutter with 4:1 conduction\"],\n correctIndex: 1,\n explanation: \"The abrupt onset, rate over 150-180 with no visible P waves, and regular narrow QRS is classic SVT — sinus tach ramps up gradually and rarely reaches this rate with hidden P waves.\",\n },\n {\n prompt: \"Why does adenosine work as a treatment for SVT?\",\n choices: [\"It permanently destroys the reentrant pathway\", \"It briefly blocks conduction through the AV node, interrupting the reentrant circuit\", \"It increases the atrial rate to override the SVT\", \"It widens the QRS complex\"],\n correctIndex: 1,\n explanation: \"Adenosine causes a very brief, complete AV node block — long enough to break the reentry loop that's sustaining the SVT, often resetting the rhythm back to sinus.\",\n },\n ],\n },\n {\n id: \"pjc\",\n name: \"Premature Junctional Contraction (PJC)\",\n category: \"Junctional\",\n free: false,\n sortOrder: 8,\n rate: \"Underlying rhythm rate, with early beats\",\n regularity: \"Irregular (early beat interrupts the pattern)\",\n pWave: \"Absent, inverted, or after the QRS (retrograde)\",\n prInterval: \"Short if a retrograde P wave is present\",\n qrs: \"Narrow\",\n summary: \"An early beat originating from the AV junction rather than the SA node or atria — the junction can conduct upward into the atria (inverted/retrograde P) as well as down to the ventricles.\",\n clinicalNote: \"Distinguish from a PAC by the P wave: absent, inverted, or appearing after the QRS rather than a normal upright P wave before it.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"junctional\", baseRateMin: 60, baseRateMax: 90 },\n questions: [\n {\n prompt: \"An early narrow QRS appears with no visible P wave before it, but there's a small inverted deflection just after the QRS. What best explains this beat?\",\n choices: [\"Premature Atrial Contraction\", \"Premature Junctional Contraction with a retrograde P wave\", \"Third-degree AV block\", \"Premature Ventricular Contraction\"],\n correctIndex: 1,\n explanation: \"A junctional beat can conduct backward into the atria, producing an inverted P wave that shows up after (or hidden within) the QRS rather than before it.\",\n },\n {\n prompt: \"What differentiates a PJC from a PAC on a strip?\",\n choices: [\"PJCs have a wide QRS and PACs don't\", \"PJCs lack a normal upright P wave before the QRS; PACs have an abnormal but present upright P wave before it\", \"PJCs are always symptomatic and PACs never are\", \"There is no meaningful difference\"],\n correctIndex: 1,\n explanation: \"The key distinction is the P wave: a PAC still has one before the QRS (just oddly shaped), while a PJC's P wave is absent, inverted, or retrograde.\",\n },\n ],\n },\n {\n id: \"junctional\",\n name: \"Junctional Rhythm\",\n category: \"Junctional\",\n free: false,\n sortOrder: 9,\n rate: \"40-60 bpm\",\n regularity: \"Regular\",\n pWave: \"Absent, inverted, or after the QRS\",\n prInterval: \"Short or not measurable\",\n qrs: \"Narrow\",\n summary: \"The AV junction takes over as the heart's pacemaker when the SA node fails to fire or its impulse doesn't reach the ventricles — an intrinsic 'backup' rate of 40-60.\",\n clinicalNote: \"Treat the underlying cause (often SA node dysfunction) rather than the rhythm itself if the patient is stable; symptomatic patients may need atropine or pacing, same as symptomatic bradycardia.\",\n waveform: { pattern: \"regular\", rateMin: 40, rateMax: 60, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A monitor shows a regular narrow-complex rhythm at 48 bpm with no visible P waves. What is the most likely rhythm?\",\n choices: [\"Sinus Bradycardia\", \"Junctional Rhythm\", \"Third-degree AV Block\", \"Idioventricular Rhythm\"],\n correctIndex: 1,\n explanation: \"A regular rate in the 40-60 range with a narrow QRS and no P waves points to the AV junction acting as the pacemaker, not the SA node (which would show P waves) or the ventricles (which would show a wide QRS).\",\n },\n {\n prompt: \"Why does a junctional rhythm typically run at 40-60 bpm rather than faster?\",\n choices: [\"That's the AV junction's own intrinsic backup pacing rate\", \"It's always a sign of digoxin toxicity\", \"The ventricles are pacing themselves at that rate\", \"It matches the SA node's normal rate\"],\n correctIndex: 0,\n explanation: \"The cardiac conduction system has tiered intrinsic backup rates — SA node fastest, AV junction next at 40-60, ventricles slowest — and junctional rhythm reflects the AV junction's own rate when it takes over.\",\n },\n ],\n },\n {\n id: \"accel-junctional\",\n name: \"Accelerated Junctional Rhythm\",\n category: \"Junctional\",\n free: false,\n sortOrder: 10,\n rate: \"60-100 bpm\",\n regularity: \"Regular\",\n pWave: \"Absent, inverted, or after the QRS\",\n prInterval: \"Short or not measurable\",\n qrs: \"Narrow\",\n summary: \"Same origin as a junctional rhythm, but the junction is firing faster than its normal 40-60 backup rate — often from irritability (ischemia, digoxin toxicity) rather than simple SA node failure.\",\n clinicalNote: \"A rate that's 'too fast' for a junctional escape rhythm (60-100 instead of 40-60) should prompt a look at digoxin levels and electrolytes.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A regular narrow-complex rhythm at 75 bpm shows no P waves before the QRS. What distinguishes this from a plain junctional rhythm?\",\n choices: [\"The QRS is wide\", \"The rate (60-100) is faster than the typical junctional escape rate of 40-60, making this accelerated junctional\", \"There's a visible sawtooth pattern\", \"The PR interval is prolonged\"],\n correctIndex: 1,\n explanation: \"The mechanism (AV junction pacing, no true P wave before QRS) is identical to junctional rhythm — the only difference is the faster rate, which earns it the 'accelerated' label.\",\n },\n {\n prompt: \"Accelerated junctional rhythm is classically associated with which of the following?\",\n choices: [\"Athletic conditioning\", \"Digoxin toxicity or myocardial irritability\", \"Caffeine intake\", \"Normal aging\"],\n correctIndex: 1,\n explanation: \"Unlike a slow junctional escape rhythm (often benign SA node failure), an accelerated junctional focus is often irritable tissue — digoxin toxicity is a classic teaching association.\",\n },\n ],\n },\n {\n id: \"first-degree\",\n name: \"First-Degree AV Block\",\n category: \"AV Block\",\n free: false,\n sortOrder: 11,\n rate: \"Underlying rhythm rate\",\n regularity: \"Regular\",\n pWave: \"Present, one before every QRS\",\n prInterval: \"Prolonged, >0.20s, but constant\",\n qrs: \"Narrow (unless a separate bundle branch issue exists)\",\n summary: \"Every atrial impulse still reaches the ventricles, but conduction through the AV node is delayed — so the PR interval is stretched out but stays constant beat to beat.\",\n clinicalNote: \"Usually benign and often an incidental finding — it's a delay, not a dropped beat, so no beats are lost. Worth noting on the chart and monitoring for progression, but rarely urgent on its own.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: true, wide: false, prMs: 280 },\n questions: [\n {\n prompt: \"A strip shows a P wave before every QRS, a regular rhythm, but the PR interval measures 0.28s on every beat. What is this rhythm?\",\n choices: [\"Second-Degree AV Block Type I\", \"Third-Degree AV Block\", \"First-Degree AV Block\", \"Normal Sinus Rhythm\"],\n correctIndex: 2,\n explanation: \"A consistently prolonged (>0.20s) but unchanging PR interval, with every P wave still conducting to a QRS, is the definition of first-degree AV block.\",\n },\n {\n prompt: \"What is the key difference between first-degree AV block and normal sinus rhythm?\",\n choices: [\"First-degree block drops occasional QRS complexes\", \"First-degree block has a prolonged but constant PR interval; NSR's PR interval is normal (0.12-0.20s)\", \"First-degree block has no P waves\", \"There is no real difference\"],\n correctIndex: 1,\n explanation: \"The rhythm and P-QRS relationship look the same as NSR — the tell is a PR interval that's stretched past 0.20s but stays fixed beat to beat.\",\n },\n ],\n },\n {\n id: \"second-degree-1\",\n name: \"Second-Degree AV Block Type I (Wenckebach)\",\n category: \"AV Block\",\n free: false,\n sortOrder: 12,\n rate: \"Atrial rate normal; ventricular rate slightly slower due to dropped beats\",\n regularity: \"Irregular (patterned — groups of beats with a dropped QRS)\",\n pWave: \"Present, but one eventually isn't followed by a QRS\",\n prInterval: \"Progressively lengthens beat to beat until a QRS is dropped, then resets\",\n qrs: \"Narrow\",\n summary: \"The AV node conduction delay gets progressively worse with each beat until one impulse fails to conduct entirely, dropping a QRS — then the cycle resets and repeats ('longer, longer, longer, drop').\",\n clinicalNote: \"Usually a benign, often reversible pattern (inferior MI, medication effect, high vagal tone) — rarely progresses to complete block, and often just needs monitoring rather than pacing.\",\n waveform: { pattern: \"wenckebach\", rateMin: 60, rateMax: 90, startPrMs: 160, prIncrementMs: 40, cycleBeats: 4 },\n questions: [\n {\n prompt: \"On a strip, the PR interval gets progressively longer over three beats, then a P wave appears with no QRS after it, and the pattern restarts. What is this rhythm?\",\n choices: [\"First-Degree AV Block\", \"Second-Degree AV Block Type I (Wenckebach)\", \"Second-Degree AV Block Type II\", \"Third-Degree AV Block\"],\n correctIndex: 1,\n explanation: \"Progressive PR lengthening culminating in a dropped QRS, then a reset, is the hallmark 'longer, longer, longer, drop' pattern of Wenckebach.\",\n },\n {\n prompt: \"Compared to Type II second-degree block, Wenckebach (Type I) is generally considered:\",\n choices: [\"More dangerous and more likely to progress to complete block\", \"Less dangerous, often benign and reversible\", \"Identical in risk\", \"Only seen in pediatric patients\"],\n correctIndex: 1,\n explanation: \"Type I block is usually at the level of the AV node itself, tends to be transient, and rarely progresses — Type II (below the AV node) carries a higher risk of sudden progression to complete block.\",\n },\n ],\n },\n {\n id: \"second-degree-2\",\n name: \"Second-Degree AV Block Type II\",\n category: \"AV Block\",\n free: false,\n sortOrder: 13,\n rate: \"Atrial rate normal; ventricular rate depends on how many beats drop\",\n regularity: \"Irregular, but PR interval doesn't change beat to beat\",\n pWave: \"Present, with intermittently dropped QRS complexes\",\n prInterval: \"Constant on conducted beats — no progressive lengthening before the drop\",\n qrs: \"Often wide (block is usually below the AV node, in the bundle branches)\",\n summary: \"Unlike Wenckebach, the PR interval stays fixed on every conducted beat — a QRS just suddenly fails to follow a P wave with no warning lengthening beforehand. The block is typically lower in the conduction system.\",\n clinicalNote: \"Higher-risk than Type I — more likely to progress suddenly to complete heart block. Often needs a pacemaker even if currently stable.\",\n waveform: { pattern: \"type2block\", rateMin: 60, rateMax: 90, prMs: 180, dropEvery: 4, wide: true },\n questions: [\n {\n prompt: \"A strip shows a constant PR interval of 0.18s on every conducted beat, but every third P wave has no QRS following it, with no warning lengthening beforehand. What is this rhythm?\",\n choices: [\"Second-Degree AV Block Type I (Wenckebach)\", \"Second-Degree AV Block Type II\", \"First-Degree AV Block\", \"Sinus Arrhythmia\"],\n correctIndex: 1,\n explanation: \"A fixed PR interval with sudden, unpredictable dropped beats (no progressive lengthening) is the defining feature that separates Type II from Wenckebach.\",\n },\n {\n prompt: \"Why is Type II second-degree block generally treated more aggressively than Type I?\",\n choices: [\"It's always asymptomatic\", \"It carries a higher risk of sudden, unpredictable progression to complete heart block\", \"It only occurs in healthy young athletes\", \"It resolves on its own within minutes\"],\n correctIndex: 1,\n explanation: \"Because the block sits below the AV node (in the bundle branches), it's less stable and can progress abruptly and without warning to third-degree block — often prompting pacemaker placement even in stable patients.\",\n },\n ],\n },\n {\n id: \"third-degree\",\n name: \"Third-Degree (Complete) AV Block\",\n category: \"AV Block\",\n free: false,\n sortOrder: 14,\n rate: \"Atrial rate normal; ventricular rate slow (40-60 junctional or <40 ventricular escape)\",\n regularity: \"Both P waves and QRS complexes are regular, but independent of each other\",\n pWave: \"Present, marching out at their own regular rate\",\n prInterval: \"Not measurable — completely variable, no relationship between P and QRS\",\n qrs: \"Narrow (junctional escape) or wide (ventricular escape), depending on where the escape pacemaker sits\",\n summary: \"No atrial impulses reach the ventricles at all — the atria and ventricles are being paced completely independently ('AV dissociation'), with the ventricles relying entirely on a junctional or ventricular escape rhythm to keep beating.\",\n clinicalNote: \"This is a true emergency if the escape rate is too slow to maintain perfusion — transcutaneous pacing and/or a permanent pacemaker are typically needed. Do not give AV-node-blocking drugs.\",\n waveform: { pattern: \"thirdDegree\", atrialRateMin: 70, atrialRateMax: 100, ventricularRateMin: 30, ventricularRateMax: 50, wide: false },\n questions: [\n {\n prompt: \"A strip shows P waves marching out regularly at 90 bpm and QRS complexes marching out regularly at 38 bpm, with no consistent relationship between the two. What is this rhythm?\",\n choices: [\"Second-Degree AV Block Type II\", \"Sinus Arrhythmia\", \"Third-Degree (Complete) AV Block\", \"Atrial Fibrillation\"],\n correctIndex: 2,\n explanation: \"Two independently regular rates — one atrial, one ventricular — with no fixed PR relationship is the signature of complete AV dissociation.\",\n },\n {\n prompt: \"A patient in third-degree AV block with a ventricular rate of 32 and altered mental status needs which immediate intervention?\",\n choices: [\"Adenosine\", \"Vagal maneuvers\", \"Transcutaneous pacing\", \"Observation only\"],\n correctIndex: 2,\n explanation: \"A symptomatic, hemodynamically unstable bradycardia from complete heart block is a pacing emergency — adenosine and vagal maneuvers are for fast rhythms, not slow ones, and observation risks further deterioration.\",\n },\n ],\n },\n {\n id: \"pvc\",\n name: \"Premature Ventricular Contraction (PVC)\",\n category: \"Ventricular\",\n free: true,\n sortOrder: 15,\n rate: \"Underlying rhythm rate, with early wide beats\",\n regularity: \"Irregular (early beat interrupts the pattern)\",\n pWave: \"None associated with the early beat\",\n prInterval: \"Not applicable for the PVC itself\",\n qrs: \"Wide (>0.12s) and bizarre-looking, often followed by a compensatory pause\",\n summary: \"An ectopic focus in the ventricle fires early, bypassing the normal conduction pathway, producing a wide, oddly-shaped QRS with no preceding P wave.\",\n clinicalNote: \"Occasional PVCs are common and often benign. Frequent, multifocal, or PVCs falling on the T wave of the prior beat (R-on-T) raise concern for triggering a lethal rhythm and warrant closer attention.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", baseRateMin: 60, baseRateMax: 90 },\n questions: [\n {\n prompt: \"On an otherwise regular strip, a wide, bizarre-looking QRS appears early with no P wave before it, followed by a pause before the next normal beat. What is this?\",\n choices: [\"Premature Atrial Contraction\", \"Premature Junctional Contraction\", \"Premature Ventricular Contraction\", \"Second-degree AV block\"],\n correctIndex: 2,\n explanation: \"A wide, early QRS with no preceding P wave is the classic PVC picture — the wide complex reflects the impulse spreading through ventricular muscle directly, not the normal fast conduction pathway.\",\n },\n {\n prompt: \"Which finding about a patient's PVCs would be most concerning and worth flagging urgently?\",\n choices: [\"A single isolated PVC once during an 8-hour shift\", \"PVCs from multiple different ventricular sites (multifocal) or landing on the preceding T wave (R-on-T)\", \"A PVC that looks identical to the one seen an hour earlier\", \"PVCs only occurring while the patient is asleep\"],\n correctIndex: 1,\n explanation: \"Multifocal PVCs suggest more irritable ventricular tissue, and R-on-T PVCs can land during the heart's vulnerable repolarization window and trigger V-tach or V-fib — both are higher-risk patterns than an isolated, uniform PVC.\",\n },\n ],\n },\n {\n id: \"idioventricular\",\n name: \"Idioventricular Rhythm\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 16,\n rate: \"20-40 bpm\",\n regularity: \"Regular\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, >0.12s\",\n summary: \"When both the SA node and the AV junction fail to pace, the ventricles fall back on their own intrinsic, very slow escape rate — the pacemaker of last resort.\",\n clinicalNote: \"This rate is rarely enough to sustain adequate perfusion on its own — treat the underlying cause and prepare for pacing; this is often a peri-arrest rhythm.\",\n waveform: { pattern: \"regular\", rateMin: 20, rateMax: 40, hasPWave: false, wide: true },\n questions: [\n {\n prompt: \"A monitor shows a regular, wide-complex rhythm at 28 bpm with no identifiable P waves anywhere on the strip. What is the most likely rhythm?\",\n choices: [\"Junctional Rhythm\", \"Idioventricular Rhythm\", \"Ventricular Tachycardia\", \"Sinus Bradycardia\"],\n correctIndex: 1,\n explanation: \"A wide QRS at a very slow rate (20-40) with no P waves reflects the ventricles pacing themselves as the last-resort intrinsic pacemaker, after higher pacemakers have failed.\",\n },\n {\n prompt: \"Why is idioventricular rhythm considered a high-risk finding even if the patient currently has a pulse?\",\n choices: [\"It always means the patient is already in cardiac arrest\", \"The rate is usually too slow to maintain adequate perfusion and it can deteriorate further without intervention\", \"It's a completely normal variant in healthy adults\", \"It resolves without any treatment needed\"],\n correctIndex: 1,\n explanation: \"20-40 bpm is rarely enough cardiac output to perfuse the brain and organs adequately — it's often seen as a late, unstable rhythm needing urgent treatment of the underlying cause and likely pacing.\",\n },\n ],\n },\n {\n id: \"vtach\",\n name: \"Ventricular Tachycardia (Monomorphic)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 17,\n rate: \">100 bpm, often 150-250\",\n regularity: \"Regular\",\n pWave: \"Absent (or dissociated, unrelated to the QRS)\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, >0.12s, uniform shape from beat to beat ('monomorphic')\",\n summary: \"A run of three or more consecutive PVCs from the same ventricular focus at a fast, regular rate — a wide-complex tachycardia that can rapidly become unstable.\",\n clinicalNote: \"Treatment depends entirely on whether the patient has a pulse and is stable: pulseless V-tach is treated like V-fib (defibrillation, ACLS); stable V-tach with a pulse may get antiarrhythmics; unstable V-tach with a pulse needs synchronized cardioversion.\",\n waveform: { pattern: \"regular\", rateMin: 150, rateMax: 220, hasPWave: false, wide: true },\n questions: [\n {\n prompt: \"A monitor shows a regular, wide-complex rhythm at 180 bpm with a uniform QRS shape on every beat and no visible P waves. The patient has a pulse but is confused and hypotensive. What is this rhythm and the appropriate action?\",\n choices: [\"SVT with aberrancy — give adenosine\", \"Monomorphic V-tach with a pulse, unstable — prepare for synchronized cardioversion\", \"Normal sinus rhythm — no action needed\", \"Atrial fibrillation — start anticoagulation\"],\n correctIndex: 1,\n explanation: \"A fast, wide, regular, uniform rhythm with an unstable patient (altered mental status, hypotension) is unstable V-tach — synchronized cardioversion is indicated, not a rate-control drug.\",\n },\n {\n prompt: \"How is pulseless V-tach managed differently from stable V-tach with a pulse?\",\n choices: [\"Pulseless V-tach is treated exactly like a normal rhythm, no urgency\", \"Pulseless V-tach is treated like V-fib — immediate defibrillation and CPR per ACLS, not synchronized cardioversion\", \"Stable V-tach always requires immediate defibrillation\", \"There is no difference in management\"],\n correctIndex: 1,\n explanation: \"No pulse means no organized output regardless of what the monitor shows — pulseless V-tach is a cardiac arrest rhythm managed with immediate defibrillation and CPR, the same as V-fib.\",\n },\n ],\n },\n {\n id: \"torsades\",\n name: \"Torsades de Pointes\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 18,\n rate: \"150-250 bpm\",\n regularity: \"Irregular\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, with amplitude that twists around the baseline ('twisting of the points')\",\n summary: \"A distinctive polymorphic V-tach where the QRS complexes appear to spiral or twist around the isoelectric baseline — classically associated with a prolonged QT interval on the preceding baseline rhythm.\",\n clinicalNote: \"Magnesium sulfate is first-line treatment, unlike standard V-tach. Also review and stop any QT-prolonging medications contributing to the underlying cause.\",\n waveform: { pattern: \"torsades\", rateMin: 150, rateMax: 220 },\n questions: [\n {\n prompt: \"A wide-complex tachycardia shows QRS complexes that appear to twist in amplitude around the baseline, changing shape continuously rather than staying uniform. What is this rhythm?\",\n choices: [\"Monomorphic Ventricular Tachycardia\", \"Torsades de Pointes\", \"Ventricular Fibrillation\", \"Atrial Flutter\"],\n correctIndex: 1,\n explanation: \"The twisting, varying QRS amplitude (as opposed to monomorphic V-tach's uniform shape) is the defining visual feature that gives torsades its name.\",\n },\n {\n prompt: \"What is the first-line treatment for torsades de pointes, distinct from standard V-tach management?\",\n choices: [\"Amiodarone\", \"Magnesium sulfate\", \"Atropine\", \"Adenosine\"],\n correctIndex: 1,\n explanation: \"Torsades is strongly linked to a prolonged QT interval, and IV magnesium is first-line — it stabilizes the cardiac membrane even when magnesium levels are normal.\",\n },\n ],\n },\n {\n id: \"vfib\",\n name: \"Ventricular Fibrillation\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 19,\n rate: \"Not organized — no true rate\",\n regularity: \"Chaotic, no pattern\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"No identifiable QRS complexes — chaotic, disorganized waveform\",\n summary: \"Multiple ventricular sites fire chaotically and simultaneously, so the ventricles quiver instead of contracting — there is no organized electrical activity and no cardiac output whatsoever.\",\n clinicalNote: \"This is cardiac arrest. Immediate CPR and defibrillation are the only effective interventions — there is no pulse to check for or medication that substitutes for defibrillation.\",\n waveform: { pattern: \"chaotic\" },\n questions: [\n {\n prompt: \"A monitor shows a completely chaotic waveform with no identifiable P waves, QRS complexes, or any repeating pattern. The patient is unresponsive with no pulse. What is this rhythm and the immediate action?\",\n choices: [\"Asystole — begin transcutaneous pacing\", \"Ventricular Fibrillation — begin CPR and defibrillate immediately\", \"Sinus Arrhythmia — reassess in 5 minutes\", \"Atrial Fibrillation — control the rate with a beta blocker\"],\n correctIndex: 1,\n explanation: \"A chaotic, disorganized waveform with no pulse is V-fib — immediate CPR and defibrillation are the only interventions that restore organized electrical activity.\",\n },\n {\n prompt: \"Why does V-fib produce no pulse even though there's electrical activity on the monitor?\",\n choices: [\"The rate is simply too slow to generate a pulse\", \"The ventricles are quivering chaotically instead of contracting in a coordinated way, so no blood is being pumped\", \"The electrical activity is too fast to register a pulse manually\", \"V-fib patients always retain a weak pulse\"],\n correctIndex: 1,\n explanation: \"Effective pumping requires coordinated contraction — chaotic, disorganized electrical activity produces quivering muscle, not a mechanical pump stroke, so there's electrical activity but zero cardiac output.\",\n },\n ],\n },\n {\n id: \"asystole\",\n name: \"Asystole\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 20,\n rate: \"None\",\n regularity: \"Not applicable — flatline\",\n pWave: \"Absent (occasional P waves alone with no QRS can occur — 'P-wave asystole')\",\n prInterval: \"Not applicable\",\n qrs: \"None — no electrical activity\",\n summary: \"Complete absence of ventricular electrical activity — a flatline. Always confirm in more than one lead and check that leads are actually attached before treating as true asystole (a loose lead can mimic it).\",\n clinicalNote: \"Not a shockable rhythm — defibrillation does nothing for a flatline. Management is high-quality CPR, epinephrine, and searching for and treating a reversible cause (the H's and T's).\",\n waveform: { pattern: \"flatline\" },\n questions: [\n {\n prompt: \"A monitor shows a flat line with no electrical activity in any lead, confirmed with leads properly attached. The patient is unresponsive with no pulse. What is the appropriate immediate treatment?\",\n choices: [\"Immediate defibrillation\", \"High-quality CPR and epinephrine, while searching for a reversible cause — this is not a shockable rhythm\", \"Synchronized cardioversion\", \"Adenosine\"],\n correctIndex: 1,\n explanation: \"Asystole has no organized electrical activity for a shock to organize — defibrillating a flatline does nothing. CPR, epinephrine, and finding a reversible cause are the actual interventions.\",\n },\n {\n prompt: \"Before treating a flatline on the monitor as true asystole, what should always be checked first?\",\n choices: [\"The patient's blood pressure\", \"That the leads are properly attached and the rhythm is confirmed in more than one lead\", \"The patient's temperature\", \"The time of day\"],\n correctIndex: 1,\n explanation: \"A disconnected or loose lead can produce a flatline that looks exactly like asystole — always rule out an equipment/lead problem before committing to that diagnosis.\",\n },\n ],\n },\n {\n id: \"sinus-arrhythmia\",\n name: \"Sinus Arrhythmia\",\n category: \"Sinus\",\n free: false,\n sortOrder: 21,\n rate: \"60-100 bpm\",\n regularity: \"Irregular — rate cycles with breathing\",\n pWave: \"Present, upright, one before every QRS, normal shape\",\n prInterval: \"0.12-0.20s, constant\",\n qrs: \"Narrow, <0.12s\",\n summary: \"Vagal tone rises and falls with breathing, so the SA node speeds up on inspiration and slows on expiration even though it's still fully in charge of pacing.\",\n clinicalNote: \"A normal physiologic finding, especially in younger or athletic patients — no treatment needed. Non-respiratory variation in an older patient can be a clue to sinus node disease.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 100, hasPWave: true, wide: false, prMs: 160, irregular: true },\n questions: [\n {\n prompt: \"A strip shows a normal P wave before every narrow QRS and a constant PR interval, but the R-R interval visibly speeds up and slows down in a repeating pattern. What is this rhythm?\",\n choices: [\"Atrial Fibrillation\", \"Sinus Arrhythmia\", \"Second-Degree AV Block Type I\", \"Multifocal Atrial Tachycardia\"],\n correctIndex: 1,\n explanation: \"Sinus arrhythmia keeps a normal, unchanging P-QRS relationship — only the rate drifts, cycling with the respiratory pattern, unlike the chaotic irregularity of afib or MAT.\",\n },\n {\n prompt: \"What causes the cyclic rate change seen in sinus arrhythmia?\",\n choices: [\"A second competing pacemaker in the atria\", \"Vagal tone shifting with the breathing cycle, speeding the SA node on inspiration and slowing it on expiration\", \"Intermittent failure of the AV node to conduct\", \"Digoxin toxicity\"],\n correctIndex: 1,\n explanation: \"It's a normal autonomic effect — breathing modulates vagal tone, and the SA node responds by speeding up and slowing down in step with it.\",\n },\n ],\n },\n {\n id: \"sinus-pause\",\n name: \"Sinus Arrest / Sinus Pause\",\n category: \"Sinus\",\n free: false,\n sortOrder: 22,\n rate: \"Normal until the pause; escape rate depends on which pacemaker takes over\",\n regularity: \"Regular, interrupted by a pause that isn't a clean multiple of the normal P-P interval\",\n pWave: \"Normal in sinus beats; absent during the pause\",\n prInterval: \"Normal in sinus beats\",\n qrs: \"Narrow, unless a ventricular escape beat ends the pause\",\n summary: \"The SA node simply fails to fire for a beat or more. A gap under 2 seconds is called a pause; 2 seconds or longer is called an arrest — a lower pacemaker usually escapes to keep the heart beating.\",\n clinicalNote: \"Often vagally mediated and benign in a healthy young patient, but can reflect sick sinus syndrome, drug effect (beta-blockers, calcium channel blockers, digoxin), or ischemia. A long pause causing syncope is called an Adams-Stokes attack.\",\n waveform: { pattern: \"pause\", rateMin: 60, rateMax: 90, hasPWave: true, prMs: 160 },\n questions: [\n {\n prompt: \"An otherwise regular strip shows one unexpectedly long gap with no P wave or QRS, not matching any clean multiple of the normal beat-to-beat interval, before the rhythm resumes. What does this describe?\",\n choices: [\"Second-Degree AV Block Type II\", \"Sinus Arrest / Sinus Pause\", \"Atrial Flutter\", \"Third-Degree AV Block\"],\n correctIndex: 1,\n explanation: \"The SA node briefly fails to fire, producing a pause with no P wave at all — different from a block, where a P wave is present but simply fails to conduct.\",\n },\n {\n prompt: \"What is the key difference between a 'sinus pause' and 'sinus arrest'?\",\n choices: [\"Pauses only happen in children\", \"Arrest always requires a pacemaker; pauses never do\", \"They're defined by duration — a pause is under 2 seconds, arrest is 2 seconds or longer\", \"There is no real difference\"],\n correctIndex: 2,\n explanation: \"Both describe the same SA node failure — the terms just split by how long the gap lasts.\",\n },\n ],\n },\n {\n id: \"wap\",\n name: \"Wandering Atrial Pacemaker (WAP)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 23,\n rate: \"<100 bpm\",\n regularity: \"Irregularly irregular\",\n pWave: \"At least 3 distinct P-wave shapes in the same view, varying beat to beat\",\n prInterval: \"Varies beat to beat along with the P wave\",\n qrs: \"Narrow\",\n summary: \"Pacemaker control shifts back and forth among the SA node, atrial tissue, and the AV junction, so each beat's P wave looks a little different depending on where it started.\",\n clinicalNote: \"Usually a benign, often incidental finding in young athletes or older adults with pulmonary disease — no treatment needed unless symptomatic.\",\n waveform: { pattern: \"multifocal\", rateMin: 60, rateMax: 95 },\n questions: [\n {\n prompt: \"A strip under 100 bpm shows P waves that change shape and size from beat to beat — at least three distinct forms — with a correspondingly variable PR interval. What is this rhythm?\",\n choices: [\"Multifocal Atrial Tachycardia\", \"Wandering Atrial Pacemaker\", \"Atrial Fibrillation\", \"Premature Atrial Contractions\"],\n correctIndex: 1,\n explanation: \"Multiple shifting P-wave shapes under 100 bpm is WAP — the same pattern above 100 bpm is called MAT instead.\",\n },\n {\n prompt: \"What's the practical difference between Wandering Atrial Pacemaker and Multifocal Atrial Tachycardia?\",\n choices: [\"WAP has a wide QRS and MAT doesn't\", \"They're the same underlying pattern, split purely by rate — under 100 bpm is WAP, over 100 bpm is MAT\", \"WAP only occurs in infants\", \"MAT always has a single P-wave shape\"],\n correctIndex: 1,\n explanation: \"Both show the same shifting-pacemaker P-wave pattern; the rate cutoff of 100 bpm is the only thing that separates the two names.\",\n },\n ],\n },\n {\n id: \"mat\",\n name: \"Multifocal Atrial Tachycardia (MAT)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 24,\n rate: \"Usually 100-150 bpm, occasionally faster\",\n regularity: \"Irregularly irregular\",\n pWave: \"At least 3 distinct P-wave shapes in the same view\",\n prInterval: \"Variable; some P waves may not conduct\",\n qrs: \"Usually narrow\",\n summary: \"Multiple irritable atrial foci compete to pace the heart, each firing on its own, so no single organized P-wave pattern or rate emerges — often driven by hypoxia, a catecholamine surge, or an electrolyte disturbance.\",\n clinicalNote: \"Classically seen with a COPD exacerbation or decompensated heart failure — it's a marker of how sick the underlying illness is. Treat the underlying cause rather than the rhythm; AV nodal agents are used cautiously, and digoxin or cardioversion generally don't work.\",\n waveform: { pattern: \"multifocal\", rateMin: 100, rateMax: 150, irregular: true },\n questions: [\n {\n prompt: \"A COPD patient's monitor shows a chaotic rhythm at 130 bpm with at least three different P-wave shapes and a variable PR interval. What is this rhythm, and what should you focus treatment on?\",\n choices: [\"Atrial Flutter — synchronized cardioversion\", \"Multifocal Atrial Tachycardia — treat the underlying hypoxia/illness, not the rhythm directly\", \"Sinus Tachycardia — reassurance only\", \"SVT — adenosine\"],\n correctIndex: 1,\n explanation: \"MAT is a marker of underlying illness (classically COPD or heart failure) — cardioversion and digoxin generally don't work, and the priority is treating what's driving it.\",\n },\n {\n prompt: \"MAT and Wandering Atrial Pacemaker share the same multi-shaped P-wave pattern. What distinguishes MAT?\",\n choices: [\"A wide QRS\", \"A rate over 100 bpm\", \"The complete absence of P waves\", \"A fixed, unchanging PR interval\"],\n correctIndex: 1,\n explanation: \"The underlying mechanism — multiple competing atrial foci — is identical; MAT is simply the name used once the rate crosses 100 bpm.\",\n },\n ],\n },\n {\n id: \"junctional-tach\",\n name: \"Junctional Tachycardia\",\n category: \"Junctional\",\n free: false,\n sortOrder: 25,\n rate: \">100 bpm\",\n regularity: \"Regular\",\n pWave: \"Retrograde (inverted) if visible — may fall before, within, or after the QRS\",\n prInterval: \"Short (<0.12s) if a P wave precedes the QRS; often unmeasurable\",\n qrs: \"Narrow, unless a pre-existing bundle branch block is present\",\n summary: \"The AV junction fires faster than the SA node and takes over as pacemaker, sending impulses down to the ventricles normally but backward into the atria — producing the inverted P waves when they're visible at all.\",\n clinicalNote: \"Classically associated with digoxin toxicity; also seen with ischemia, myocarditis, or after cardiac surgery. Typically doesn't respond to vagal maneuvers, which helps distinguish it from a re-entrant SVT.\",\n waveform: { pattern: \"regular\", rateMin: 100, rateMax: 160, hasPWave: false, wide: false },\n questions: [\n {\n prompt: \"A monitor shows a regular, narrow-complex rhythm at 120 bpm with no clearly visible P waves, unresponsive to vagal maneuvers. Which cause should specifically come to mind?\",\n choices: [\"Caffeine intake\", \"Digoxin toxicity\", \"Athletic conditioning\", \"Dehydration\"],\n correctIndex: 1,\n explanation: \"Junctional tachycardia is a classic digoxin toxicity finding — it's also one of the clues that helps separate it from a re-entrant SVT, which usually does respond to vagal maneuvers.\",\n },\n {\n prompt: \"Why are P waves inverted (retrograde) in junctional tachycardia when they're visible at all?\",\n choices: [\"The SA node is firing backward\", \"The AV junction paces the ventricles normally but conducts backward up into the atria\", \"The atria are fibrillating\", \"The QRS is masking a normal upright P wave\"],\n correctIndex: 1,\n explanation: \"The junction sits between the atria and ventricles — when it takes over pacing, the impulse still reaches the ventricles normally but has to travel backward to reach the atria, producing an inverted P wave.\",\n },\n ],\n },\n {\n id: \"aivr\",\n name: \"Accelerated Idioventricular Rhythm (AIVR)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 26,\n rate: \"40-100 bpm (some sources extend to 110-120)\",\n regularity: \"Regular\",\n pWave: \"Often dissociated from the QRS; occasional fusion/capture beats\",\n prInterval: \"Not applicable (P and QRS are dissociated) except at fusion beats\",\n qrs: \"Wide, bizarre, ventricular in origin\",\n summary: \"An irritable focus in the ventricle fires slightly faster than the SA node and briefly takes over pacing — 'accelerated' because it's faster than a normal ventricular escape rhythm (20-40) but not fast enough to call it V-tach.\",\n clinicalNote: \"A classic, usually benign finding after reperfusion (post-thrombolysis or PCI in a STEMI) — a 'reperfusion arrhythmia.' It's typically self-limited; treating it with antiarrhythmics is generally avoided since it can suppress the only functioning ventricular rhythm.\",\n waveform: { pattern: \"regular\", rateMin: 40, rateMax: 100, hasPWave: false, wide: true },\n questions: [\n {\n prompt: \"Shortly after a patient receives reperfusion therapy for a STEMI, the monitor shows a regular, wide-complex rhythm at 75 bpm. What is the most likely rhythm, and the appropriate response?\",\n choices: [\"Ventricular Tachycardia — synchronized cardioversion\", \"Accelerated Idioventricular Rhythm — usually benign, generally just observe\", \"Third-Degree AV Block — transcutaneous pacing\", \"Asystole — begin CPR\"],\n correctIndex: 1,\n explanation: \"AIVR classically shows up right after reperfusion and is usually a benign, self-limited finding — treating it aggressively can actually suppress the ventricular rhythm keeping the patient perfused.\",\n },\n {\n prompt: \"What separates AIVR from a slow Ventricular Tachycardia?\",\n choices: [\"AIVR always has a narrow QRS\", \"Rate is the main distinguishing feature, though the two can overlap — AIVR is generally under 100-120 bpm\", \"AIVR only occurs in children\", \"V-tach never has AV dissociation\"],\n correctIndex: 1,\n explanation: \"Both are wide-complex ventricular rhythms — rate is the main practical distinguishing feature, though sources acknowledge some overlap at the upper end of AIVR's range.\",\n },\n ],\n },\n {\n id: \"v-paced\",\n name: \"Ventricular Paced Rhythm\",\n category: \"Other\",\n free: false,\n sortOrder: 27,\n rate: \"Set by the pacemaker's programmed rate (commonly ~60-70 bpm baseline)\",\n regularity: \"Regular\",\n pWave: \"Absent or dissociated — a single-chamber ventricular pacemaker doesn't sense or pace the atrium\",\n prInterval: \"Not applicable for paced beats\",\n qrs: \"Wide, preceded by a sharp pacing spike; often resembles a left bundle branch block pattern\",\n summary: \"A wire in the right ventricle delivers an electrical stimulus directly to the heart muscle whenever the intrinsic rate drops below the device's set threshold, producing a wide, bizarre QRS with a pacing spike right before it.\",\n clinicalNote: \"This is the expected, normal appearance for a functioning single-chamber ventricular pacemaker. Standard STEMI criteria don't apply to paced beats — watch instead for failure to capture (a spike with no QRS following it) or failure to sense.\",\n waveform: { pattern: \"regular\", rateMin: 60, rateMax: 72, hasPWave: false, wide: true, pacedSpike: true },\n questions: [\n {\n prompt: \"A strip shows a sharp vertical spike immediately before every wide, bizarre QRS, at a fixed rate of 70 bpm. What does this represent?\",\n choices: [\"Wolff-Parkinson-White pattern\", \"A functioning ventricular paced rhythm\", \"Torsades de Pointes\", \"First-Degree AV Block\"],\n correctIndex: 1,\n explanation: \"The pacing spike right before a wide QRS is the signature of a ventricular pacemaker firing — the device is generating the beat directly rather than the heart's own conduction system.\",\n },\n {\n prompt: \"A pacing spike appears on the strip but is NOT followed by a QRS complex. What does this indicate?\",\n choices: [\"Normal pacemaker function\", \"Failure to capture — the pacing stimulus isn't triggering a ventricular contraction\", \"Sinus arrhythmia\", \"First-degree AV block\"],\n correctIndex: 1,\n explanation: \"A spike with no resulting QRS means the electrical stimulus reached the tissue but failed to depolarize it — a pacemaker malfunction called failure to capture, worth flagging urgently.\",\n },\n ],\n },\n {\n id: \"wpw\",\n name: \"Wolff-Parkinson-White (WPW) Pattern\",\n category: \"Other\",\n free: false,\n sortOrder: 28,\n rate: \"Normal at baseline (WPW is a conduction pattern, not itself a tachycardia)\",\n regularity: \"Regular at baseline\",\n pWave: \"Normal sinus P wave\",\n prInterval: \"Short, <0.12s\",\n qrs: \"Wide, >0.12s, with a slurred, slowed initial upstroke (the 'delta wave')\",\n summary: \"An extra electrical connection between atria and ventricles (an accessory pathway) bypasses the AV node's normal delay, so part of the ventricle is activated early — producing the short PR interval and the slurred delta-wave upstroke where the early and normal wavefronts fuse.\",\n clinicalNote: \"Predisposes to re-entrant tachycardias and, critically, to very rapid ventricular rates if the patient develops atrial fibrillation, since the accessory pathway lacks the AV node's rate-limiting property. AV-node-blocking drugs (adenosine, beta-blockers, calcium channel blockers, digoxin) are contraindicated in pre-excited afib because they can paradoxically speed conduction down the bypass tract.\",\n waveform: { pattern: \"regular\", rateMin: 65, rateMax: 90, hasPWave: true, wide: true, prMs: 90, delta: true },\n questions: [\n {\n prompt: \"A resting strip shows a short PR interval and a QRS with a slurred, slowed initial upstroke before the sharp spike. What does this describe?\",\n choices: [\"First-Degree AV Block\", \"Wolff-Parkinson-White (WPW) pattern\", \"Right bundle branch block\", \"Sinus Tachycardia\"],\n correctIndex: 1,\n explanation: \"A short PR interval plus a delta wave — that slurred upstroke — is the defining ECG signature of pre-excitation from an accessory pathway.\",\n },\n {\n prompt: \"Why are adenosine, beta-blockers, and calcium channel blockers dangerous in a WPW patient who develops atrial fibrillation?\",\n choices: [\"They have no effect on the accessory pathway either way\", \"They slow the AV node, which can paradoxically push more of the fast atrial activity down the unprotected accessory pathway to the ventricles\", \"They only work in adults over 65\", \"They cure the accessory pathway permanently\"],\n correctIndex: 1,\n explanation: \"Unlike the AV node, the accessory pathway has no built-in rate limiter — blocking the AV node removes the 'safety valve' and can let dangerously fast atrial rates conduct straight to the ventricles, risking V-fib.\",\n },\n ],\n },\n {\n id: \"atrial-bigeminy\",\n name: \"Atrial Bigeminy\",\n category: \"Atrial\",\n free: false,\n sortOrder: 29,\n rate: \"Underlying sinus rate variable; every other beat is an early PAC, so overall rate often looks near-normal to mildly irregular\",\n regularity: \"Regularly irregular — patterned couplet of sinus beat + PAC repeating\",\n pWave: \"Alternating normal sinus P wave and a premature, differently-shaped ectopic P wave\",\n prInterval: \"Sinus beats normal (0.12-0.20s); ectopic P wave PR interval often shortened or variable\",\n qrs: \"Narrow (<0.12s) unless the PAC is aberrantly conducted\",\n summary: \"An irritable atrial focus fires prematurely after every normal sinus beat, producing a repeating two-beat pattern of 'normal-early, normal-early.'\",\n clinicalNote: \"Usually benign and related to caffeine, stress, or stretch (e.g., atrial enlargement); frequent bigeminy can herald atrial fibrillation and warrants clinical correlation, not automatic treatment.\",\n waveform: { pattern: \"patternedEctopy\", unit: 2, ectopicSubtype: \"atrial\", baseRateMin: 70, baseRateMax: 90 },\n questions: [\n {\n prompt: \"Atrial bigeminy describes a rhythm where:\",\n choices: [\"Every third beat is a PAC\", \"Every other beat is a PAC\", \"Two PACs occur in a row then a pause\", \"PACs occur randomly with no pattern\"],\n correctIndex: 1,\n explanation: \"Bigeminy means a 2-beat repeating pattern — one normal sinus beat followed by one premature atrial beat, repeating.\",\n },\n {\n prompt: \"A patient with new frequent atrial bigeminy should raise concern for eventual progression to:\",\n choices: [\"Third-degree AV block\", \"Atrial fibrillation\", \"Ventricular fibrillation\", \"Sinus arrest\"],\n correctIndex: 1,\n explanation: \"Frequent atrial ectopy, including bigeminy, is a recognized precursor pattern for atrial fibrillation.\",\n },\n ],\n },\n {\n id: \"atrial-trigeminy\",\n name: \"Atrial Trigeminy\",\n category: \"Atrial\",\n free: false,\n sortOrder: 30,\n rate: \"Variable underlying sinus rate\",\n regularity: \"Regularly irregular — repeating 3-beat group (two sinus beats + one PAC)\",\n pWave: \"Two consecutive normal P waves followed by one premature/abnormally-shaped P wave, repeating\",\n prInterval: \"Normal for sinus beats; variable for the ectopic beat\",\n qrs: \"Narrow unless aberrant conduction present\",\n summary: \"Similar mechanism to atrial bigeminy but the ectopic atrial focus fires every third beat instead of every other beat, creating a repeating triplet grouping.\",\n clinicalNote: \"Typically benign; assess for stimulant use, hyperthyroidism, electrolyte disturbance, or structural atrial disease if frequent or symptomatic.\",\n waveform: { pattern: \"patternedEctopy\", unit: 3, ectopicSubtype: \"atrial\", baseRateMin: 70, baseRateMax: 90 },\n questions: [\n {\n prompt: \"What distinguishes trigeminy from bigeminy?\",\n choices: [\"Trigeminy has 3 PACs in a row\", \"Trigeminy repeats every 3rd beat instead of every 2nd\", \"Trigeminy only occurs in the ventricles\", \"Trigeminy is always pathologic\"],\n correctIndex: 1,\n explanation: \"The repeating group size is three beats in trigeminy versus two in bigeminy.\",\n },\n {\n prompt: \"Isolated atrial trigeminy in an asymptomatic patient with no structural heart disease typically requires:\",\n choices: [\"Emergent cardioversion\", \"No specific treatment, address triggers\", \"Immediate pacemaker\", \"IV amiodarone\"],\n correctIndex: 1,\n explanation: \"Benign ectopy in a structurally normal heart is usually managed by addressing triggers (caffeine, stress) rather than pharmacologic or electrical intervention.\",\n },\n ],\n },\n {\n id: \"pvc-bigeminy\",\n name: \"PVC Bigeminy (Ventricular Bigeminy)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 31,\n rate: \"Underlying rate variable; effective pulse rate may be lower if PVCs are non-perfusing\",\n regularity: \"Regularly irregular — repeating pattern of one normal beat then one PVC\",\n pWave: \"Normal sinus P wave on the sinus beat; no related P wave before the PVC\",\n prInterval: \"Normal on sinus beats; not applicable to the PVC\",\n qrs: \"Narrow on sinus beats; wide (>0.12s), bizarre-shaped on every other beat (the PVC)\",\n summary: \"A ventricular ectopic focus fires after every normal beat, producing an alternating pattern of one narrow sinus complex and one wide, premature ventricular complex.\",\n clinicalNote: \"Can occur in normal hearts but frequent bigeminy (especially with a PVC burden >10-15%) is associated with PVC-induced cardiomyopathy over time and warrants further workup.\",\n waveform: { pattern: \"patternedEctopy\", unit: 2, ectopicSubtype: \"ventricular\", baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"On palpation, PVC bigeminy classically feels like:\",\n choices: [\"A perfectly regular pulse\", \"Every other beat is weak or dropped\", \"A slow, regular bradycardia\", \"No palpable pulse at all\"],\n correctIndex: 1,\n explanation: \"Because PVCs often don't generate an adequate stroke volume, alternating strong/weak beats can be felt.\",\n },\n {\n prompt: \"A sustained high PVC burden over months is most associated with:\",\n choices: [\"Improved ejection fraction\", \"PVC-induced cardiomyopathy\", \"Resolution of hypertension\", \"Guaranteed benign outcome\"],\n correctIndex: 1,\n explanation: \"Chronic, frequent PVCs can lead to a reversible dilated cardiomyopathy if the burden is high enough and untreated.\",\n },\n ],\n },\n {\n id: \"pvc-trigeminy\",\n name: \"PVC Trigeminy (Ventricular Trigeminy)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 32,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Regularly irregular — repeating 3-beat group (two normal beats + one PVC)\",\n pWave: \"Normal P waves precede the sinus beats; none associated with the PVC\",\n prInterval: \"Normal on sinus beats\",\n qrs: \"Narrow x2 then one wide, bizarre PVC, repeating\",\n summary: \"A ventricular ectopic focus discharges every third beat, producing a repeating triplet of two normal conducted beats followed by one premature wide complex.\",\n clinicalNote: \"Same clinical considerations as bigeminy — evaluate PVC burden, symptoms, and underlying structural heart disease or electrolyte abnormality (especially hypokalemia/hypomagnesemia).\",\n waveform: { pattern: \"patternedEctopy\", unit: 3, ectopicSubtype: \"ventricular\", baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"A repeating pattern of two normal QRS complexes followed by one wide bizarre complex describes:\",\n choices: [\"PVC bigeminy\", \"PVC trigeminy\", \"Ventricular tachycardia\", \"Torsades de pointes\"],\n correctIndex: 1,\n explanation: \"The three-beat repeating group (2 normal + 1 PVC) is the defining feature of trigeminy.\",\n },\n {\n prompt: \"Which electrolyte disturbances commonly increase ventricular ectopy such as trigeminy?\",\n choices: [\"Hyperkalemia and hypercalcemia\", \"Hypokalemia and hypomagnesemia\", \"Hypernatremia and hypocalcemia\", \"None, electrolytes are unrelated\"],\n correctIndex: 1,\n explanation: \"Low potassium and low magnesium increase myocardial irritability and are classic reversible triggers for PVCs.\",\n },\n ],\n },\n {\n id: \"pvc-couplet\",\n name: \"PVC Couplet (Paired PVCs)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 33,\n rate: \"Underlying sinus rate variable; the couplet itself occurs rapidly\",\n regularity: \"Irregular — two consecutive PVCs occur back-to-back\",\n pWave: \"None associated with either PVC\",\n prInterval: \"Not applicable to the couplet beats\",\n qrs: \"Two consecutive wide, bizarre complexes with no normal beat in between, followed by a compensatory pause\",\n summary: \"Two PVCs fire consecutively without an intervening sinus beat, representing a brief run of ventricular ectopy one beat short of being called a 'run' (three or more defines non-sustained VT).\",\n clinicalNote: \"Couplets are more concerning than isolated PVCs because they signal increased ventricular irritability and a higher likelihood of progressing to sustained ventricular tachycardia.\",\n waveform: { pattern: \"burstEctopy\", burstLength: 2, baseRateMin: 65, baseRateMax: 85, burstRateMin: 150, burstRateMax: 180 },\n questions: [\n {\n prompt: \"A PVC couplet is defined as:\",\n choices: [\"One PVC followed by a pause\", \"Two consecutive PVCs in a row\", \"Three or more consecutive PVCs\", \"A PVC that lands on a T wave\"],\n correctIndex: 1,\n explanation: \"A couplet is specifically two back-to-back PVCs; three or more in a row is termed a run.\",\n },\n {\n prompt: \"Compared to isolated unifocal PVCs, PVC couplets carry:\",\n choices: [\"The same clinical significance\", \"Lower risk of progressing to VT\", \"Higher risk of progressing to VT\", \"No clinical significance\"],\n correctIndex: 2,\n explanation: \"Couplets indicate greater myocardial irritability and a higher likelihood of degenerating into sustained ventricular arrhythmias.\",\n },\n ],\n },\n {\n id: \"pvc-triplet-nsvt\",\n name: \"PVC Triplet / Non-Sustained Ventricular Tachycardia (NSVT)\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 34,\n rate: \"Ventricular rate during the run typically 100-250 bpm\",\n regularity: \"The run itself is regular or near-regular; overall strip is irregular due to interruption of sinus rhythm\",\n pWave: \"None during the run; dissociated sinus P waves may be seen marching through\",\n prInterval: \"Not applicable during the run\",\n qrs: \"Three or more consecutive wide, bizarre complexes lasting <30 seconds and self-terminating\",\n summary: \"Three or more consecutive PVCs constitute a run of ventricular tachycardia; when it self-terminates within 30 seconds without hemodynamic collapse, it is classified as non-sustained VT.\",\n clinicalNote: \"NSVT in a structurally normal heart is often benign, but in the setting of prior MI, cardiomyopathy, or reduced ejection fraction it is a marker of increased risk for sudden cardiac death and warrants further evaluation.\",\n waveform: { pattern: \"burstEctopy\", burstLength: 5, baseRateMin: 65, baseRateMax: 85, burstRateMin: 160, burstRateMax: 220 },\n questions: [\n {\n prompt: \"How many consecutive PVCs are required to call a run \\\"ventricular tachycardia\\\" rather than a couplet?\",\n choices: [\"Two\", \"Three or more\", \"Five or more\", \"Ten or more\"],\n correctIndex: 1,\n explanation: \"Three or more consecutive ventricular beats at a rate over 100 bpm meets the definition of VT; a run lasting <30 seconds without collapse is termed non-sustained.\",\n },\n {\n prompt: \"NSVT is most clinically concerning when found in a patient with:\",\n choices: [\"A structurally normal heart and no symptoms\", \"Reduced ejection fraction after prior MI\", \"Well-controlled hypertension only\", \"Isolated caffeine use\"],\n correctIndex: 1,\n explanation: \"NSVT in structural heart disease, especially post-MI with reduced EF, is an independent risk marker for sudden cardiac death.\",\n },\n ],\n },\n {\n id: \"unifocal-pvcs\",\n name: \"Unifocal PVCs\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 35,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Irregular due to premature beats\",\n pWave: \"None associated with the PVCs\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, bizarre PVCs that are all identical in morphology to one another, arising from a single ventricular ectopic focus\",\n summary: \"All PVCs on the strip originate from the same irritable focus, so each one looks identical in shape, width, and axis.\",\n clinicalNote: \"Generally considered lower risk than multifocal PVCs because a single consistent focus is more predictable and often more benign, though burden and underlying heart disease still matter.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", count: 3, baseRateMin: 65, baseRateMax: 90 },\n questions: [\n {\n prompt: \"Unifocal PVCs are characterized by:\",\n choices: [\"Varying shapes from beat to beat\", \"Identical morphology from beat to beat\", \"Occurring only in pairs\", \"Always being asymptomatic\"],\n correctIndex: 1,\n explanation: \"\\\"Unifocal\\\" means one origin site, so every PVC has the same QRS morphology.\",\n },\n {\n prompt: \"Compared to multifocal PVCs, unifocal PVCs are generally considered:\",\n choices: [\"More dangerous\", \"Less concerning, arising from a single stable focus\", \"Impossible to distinguish clinically\", \"Always caused by digoxin toxicity\"],\n correctIndex: 1,\n explanation: \"A single consistent ectopic focus is typically viewed as lower risk than multiple competing irritable foci.\",\n },\n ],\n },\n {\n id: \"multifocal-pvcs\",\n name: \"Multifocal PVCs\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 36,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Irregular\",\n pWave: \"None associated with the PVCs\",\n prInterval: \"Not applicable\",\n qrs: \"Wide, bizarre PVCs with varying morphology and axis from beat to beat, indicating more than one ventricular ectopic focus\",\n summary: \"PVCs arise from two or more different irritable ventricular sites, so their shape, width, and direction differ from one PVC to the next on the same strip.\",\n clinicalNote: \"Multifocal PVCs suggest a more diffusely irritable or diseased myocardium (ischemia, electrolyte disturbance, hypoxia) and are generally regarded as higher risk than unifocal PVCs.\",\n waveform: { pattern: \"multifocal\", wide: true, rateMin: 65, rateMax: 90, irregular: true },\n questions: [\n {\n prompt: \"Multifocal PVCs are identified by:\",\n choices: [\"Same shape every time\", \"Different QRS morphologies from beat to beat\", \"Occurring exactly every other beat\", \"A narrow QRS complex\"],\n correctIndex: 1,\n explanation: \"Multiple ectopic foci produce PVCs with varying shapes and axes on the same tracing.\",\n },\n {\n prompt: \"Multifocal PVCs are most concerning as a sign of:\",\n choices: [\"Normal aging only\", \"Diffuse myocardial irritability from ischemia, hypoxia, or electrolyte imbalance\", \"Excellent cardiac health\", \"Vagal tone\"],\n correctIndex: 1,\n explanation: \"Multiple competing ectopic foci suggest a broader insult to the myocardium and carry higher clinical concern than a single stable focus.\",\n },\n ],\n },\n {\n id: \"r-on-t-phenomenon\",\n name: \"R-on-T Phenomenon\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 37,\n rate: \"Underlying rate variable\",\n regularity: \"Irregular; the PVC falls during the vulnerable period of the preceding beat's T wave\",\n pWave: \"None associated with the PVC\",\n prInterval: \"Not applicable\",\n qrs: \"A PVC whose R wave lands directly on the peak/downslope of the preceding T wave\",\n summary: \"When a premature ventricular beat strikes during the relative refractory period marked by the T wave, it can trigger reentry and precipitate ventricular tachycardia or fibrillation.\",\n clinicalNote: \"R-on-T PVCs are considered a higher-risk ectopy pattern, particularly in the setting of acute ischemia or a prolonged QT interval, and clinicians should watch closely for degeneration into VT/VF or torsades.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", count: 1, baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"R-on-T phenomenon describes a PVC that lands on:\",\n choices: [\"The P wave of the prior beat\", \"The T wave of the prior beat\", \"The QRS of the prior beat\", \"The isoelectric baseline\"],\n correctIndex: 1,\n explanation: \"The T wave represents the vulnerable period of ventricular repolarization; a PVC striking there risks precipitating a malignant arrhythmia.\",\n },\n {\n prompt: \"R-on-T is of greatest concern in a patient who also has:\",\n choices: [\"A short PR interval\", \"A prolonged QT interval or acute ischemia\", \"Sinus arrhythmia\", \"First-degree AV block\"],\n correctIndex: 1,\n explanation: \"A prolonged QT widens the vulnerable window, and acute ischemia increases myocardial irritability, both raising the risk that R-on-T triggers VT/VF or torsades.\",\n },\n ],\n },\n {\n id: \"ventricular-fusion-beat\",\n name: \"Ventricular Fusion Beat\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 38,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Occurs as an isolated irregular beat within an otherwise regular rhythm\",\n pWave: \"A sinus P wave is present, conducting simultaneously with a competing ventricular ectopic impulse\",\n prInterval: \"May appear shortened or normal depending on timing\",\n qrs: \"A single complex with a morphology intermediate between a normal narrow QRS and a wide bizarre PVC\",\n summary: \"A fusion beat happens when a supraventricular impulse and a ventricular ectopic impulse depolarize the ventricles simultaneously, blending their two QRS morphologies into one hybrid complex.\",\n clinicalNote: \"Fusion beats are a classic supportive finding for diagnosing ventricular tachycardia (a 'Dressler beat'), helping distinguish VT from SVT with aberrancy.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"ventricular\", count: 1, baseRateMin: 65, baseRateMax: 85 },\n questions: [\n {\n prompt: \"A fusion beat results from:\",\n choices: [\"Two PVCs occurring simultaneously\", \"A sinus impulse and a ventricular ectopic impulse depolarizing the ventricle at the same time\", \"Complete AV block\", \"Atrial fibrillation with rapid response\"],\n correctIndex: 1,\n explanation: \"Fusion beats blend normal conduction with a competing ventricular ectopic focus into one intermediate-shaped complex.\",\n },\n {\n prompt: \"Finding fusion beats during a wide-complex tachycardia supports a diagnosis of:\",\n choices: [\"SVT with aberrancy\", \"Ventricular tachycardia\", \"Atrial flutter\", \"Sinus tachycardia\"],\n correctIndex: 1,\n explanation: \"Fusion (and capture) beats are classic AV dissociation clues that favor VT over SVT with aberrant conduction.\",\n },\n ],\n },\n {\n id: \"aberrantly-conducted-pac-ashman\",\n name: \"Aberrantly Conducted PAC (Ashman Phenomenon)\",\n category: \"Atrial\",\n free: false,\n sortOrder: 39,\n rate: \"Underlying sinus rate variable\",\n regularity: \"Irregular due to the premature beat\",\n pWave: \"A premature, differently-shaped P wave precedes the wide beat\",\n prInterval: \"Often shortened compared to sinus beats\",\n qrs: \"Wide and bizarre-looking (commonly RBBB morphology), mimicking a PVC, but preceded by a premature P wave\",\n summary: \"A PAC that arrives early, while part of the conduction system is still refractory from the preceding long cycle, conducts aberrantly and produces a wide QRS that mimics a PVC.\",\n clinicalNote: \"Recognizing Ashman phenomenon (classically a 'long-short' cycle sequence) prevents misdiagnosing a benign aberrantly conducted PAC as a dangerous PVC, and is frequently seen at the onset of atrial fibrillation.\",\n waveform: { pattern: \"ectopic\", ectopicSubtype: \"atrial\", wide: true, count: 1, baseRateMin: 70, baseRateMax: 90 },\n questions: [\n {\n prompt: \"Ashman phenomenon classically occurs after which cycle pattern?\",\n choices: [\"A short cycle followed by a long cycle\", \"A long cycle followed by a short cycle\", \"Two equal cycles in a row\", \"Complete pause with no preceding cycle\"],\n correctIndex: 1,\n explanation: \"A long R-R interval prolongs the refractory period of the bundle branches; a subsequent short-cycle beat can then conduct aberrantly.\",\n },\n {\n prompt: \"The key clue that a wide beat is an aberrantly conducted PAC rather than a true PVC is:\",\n choices: [\"A premature P wave preceding it with typical RBBB morphology\", \"A fully compensatory pause\", \"Absence of any P wave\", \"A fixed coupling interval\"],\n correctIndex: 0,\n explanation: \"Ashman-phenomenon beats are preceded by a premature ectopic P wave and often show a classic RBBB (rSR') pattern, distinguishing them from PVCs.\",\n },\n ],\n },\n {\n id: \"junctional-escape-beat\",\n name: \"Junctional Escape Beat\",\n category: \"Junctional\",\n free: false,\n sortOrder: 40,\n rate: \"A single beat occurring at the junctional escape rate (40-60 bpm) after a pause\",\n regularity: \"An isolated beat interrupting the underlying rhythm following a pause\",\n pWave: \"Absent, inverted, or retrograde\",\n prInterval: \"Short (<0.12s) if a retrograde P precedes the QRS, or not measurable if absent\",\n qrs: \"Narrow (<0.12s), normal in shape\",\n summary: \"When the sinus node fails to fire on time, the AV junction acts as a backup pacemaker and produces a single escape beat to prevent an excessively long pause.\",\n clinicalNote: \"A single junctional escape beat is a protective safety mechanism, not itself pathologic, but its presence signals underlying sinus node dysfunction that should be evaluated.\",\n waveform: { pattern: \"pause\", rateMin: 60, rateMax: 90, hasPWave: true, prMs: 160 },\n questions: [\n {\n prompt: \"A junctional escape beat occurs because:\",\n choices: [\"The junction is diseased and firing too fast\", \"The sinus node failed to fire on time and a backup pacemaker took over for one beat\", \"The patient has WPW\", \"It follows a PVC always\"],\n correctIndex: 1,\n explanation: \"Escape beats are a protective backup mechanism that fires after the sinus node pauses too long.\",\n },\n {\n prompt: \"A single junctional escape beat should prompt evaluation for:\",\n choices: [\"Nothing, it's always normal\", \"Underlying sinus node dysfunction\", \"Ventricular fibrillation risk\", \"Digoxin toxicity only\"],\n correctIndex: 1,\n explanation: \"While the escape beat itself is protective, its occurrence indicates the sinus node paused, warranting evaluation of sinus node function.\",\n },\n ],\n },\n {\n id: \"ventricular-escape-beat\",\n name: \"Ventricular Escape Beat\",\n category: \"Ventricular\",\n free: false,\n sortOrder: 41,\n rate: \"A single beat at the ventricular escape rate (20-40 bpm) following a pause\",\n regularity: \"An isolated beat interrupting the underlying rhythm after a long pause\",\n pWave: \"Absent\",\n prInterval: \"Not applicable\",\n qrs: \"Wide (>0.12s), bizarre morphology, occurring late after a pause\",\n summary: \"When both the sinus node and the AV junction fail to initiate an impulse in time, a ventricular pacemaker cell fires as a last-resort backup to prevent asystole.\",\n clinicalNote: \"A ventricular escape beat is a life-sustaining safety mechanism; its appearance indicates significant conduction system disease and often precedes a need for pacing.\",\n waveform: { pattern: \"pause\", rateMin: 55, rateMax: 80, hasPWave: true, prMs: 160 },\n questions: [\n {\n prompt: \"A ventricular escape beat appears when:\",\n choices: [\"Both the SA node and AV junction fail to fire in time\", \"The atria are fibrillating\", \"A PVC lands on a T wave\", \"The patient is in normal sinus rhythm\"],\n correctIndex: 0,\n explanation: \"Ventricular escape is the heart's last line of defense, firing only when higher pacemakers (SA node, AV junction) fail to initiate an impulse.\",\n },\n {\n prompt: \"The presence of ventricular escape beats most strongly suggests the need to evaluate for:\",\n choices: [\"Simple sinus arrhythmia\", \"Significant conduction system disease requiring possible pacing\", \"Benign PACs\", \"Athletic heart syndrome\"],\n correctIndex: 1,\n explanation: \"Reliance on a ventricular escape mechanism reflects failure of both higher-order pacemakers and often signals a need for permanent pacing.\",\n },\n ],\n },\n {\n id: \"atrial-escape-beat\",\n name: \"Atrial Escape Beat\",\n category: \"Atrial\",\n free: false,\n sortOrder: 42,\n rate: \"A single beat occurring after a pause, originating from an ectopic atrial focus\",\n regularity: \"An isolated beat interrupting the underlying rhythm following a pause\",\n pWave: \"Present but abnormally shaped since it originates from an ectopic atrial site, not the SA node\",\n prInterval: \"May be normal or slightly different from sinus PR interval\",\n qrs: \"Narrow, normal conduction\",\n summary: \"When the SA node pauses, a subsidiary atrial pacemaker outside the sinus node fires to prevent a longer pause, producing a single beat with a differently shaped P wave but otherwise normal narrow QRS.\",\n clinicalNote: \"Like junctional escape, this is a protective mechanism reflecting transient SA node under-function rather than a primary arrhythmia requiring emergent treatment.\",\n waveform: { pattern: \"pause\", rateMin: 60, rateMax: 90, hasPWave: true, prMs: 150 },\n questions: [\n {\n prompt: \"An atrial escape beat differs from a PAC in that it:\",\n choices: [\"Comes early\", \"Comes late, after a pause, as a protective response\", \"Always has a wide QRS\", \"Never has a P wave\"],\n correctIndex: 1,\n explanation: \"A PAC is premature (early); an escape beat is, by definition, late — it fires only after the primary pacemaker fails to fire on time.\",\n },\n {\n prompt: \"The QRS of an atrial escape beat is typically:\",\n choices: [\"Wide and bizarre\", \"Narrow, since conduction through the AV node and ventricles is normal\", \"Absent entirely\", \"Always preceded by no P wave\"],\n correctIndex: 1,\n explanation: \"Since the impulse still originates above the ventricles and conducts normally through the His-Purkinje system, the QRS remains narrow.\",\n },\n ],\n },\n {\n id: \"hyperkalemia-ecg-changes\",\n name: \"Hyperkalemia ECG Pattern\",\n category: \"Other\",\n free: false,\n sortOrder: 43,\n rate: \"Variable; sinus rate may slow as severity increases\",\n regularity: \"Regular initially, progressing to irregular as severity worsens\",\n pWave: \"Flattened and widened, eventually disappearing as potassium rises further\",\n prInterval: \"Progressively prolonged, then P waves are lost\",\n qrs: \"Progressively widens; in severe hyperkalemia the QRS merges with the T wave (sine-wave pattern)\",\n summary: \"Rising extracellular potassium progressively depresses cardiac conduction velocity, producing a characteristic sequence from tall peaked T waves, to PR prolongation and flattened P waves, to QRS widening.\",\n clinicalNote: \"This is a true cardiac emergency — severity of ECG change (not the lab potassium value alone) should guide urgency of treatment with IV calcium, insulin/dextrose, and other potassium-lowering measures.\",\n waveform: { pattern: \"regular\", rateMin: 50, rateMax: 80, hasPWave: true, wide: true, prMs: 220, tAmpScale: 2.2 },\n questions: [\n {\n prompt: \"The earliest classic ECG change of hyperkalemia is:\",\n choices: [\"Widened QRS\", \"Tall, peaked, narrow-based T waves\", \"Sine wave pattern\", \"Prolonged QT\"],\n correctIndex: 1,\n explanation: \"Peaked, tented T waves are typically the earliest sign, appearing before P wave flattening and QRS widening.\",\n },\n {\n prompt: \"A sine-wave pattern on ECG in a hyperkalemic patient indicates:\",\n choices: [\"Mild, non-urgent hyperkalemia\", \"Life-threatening hyperkalemia requiring immediate treatment\", \"Normal variant\", \"Digoxin effect\"],\n correctIndex: 1,\n explanation: \"The sine-wave pattern represents merging of the widened QRS with the T wave and is a pre-terminal rhythm requiring emergent calcium administration and potassium-lowering therapy.\",\n },\n ],\n },\n];\n","createdAt",["D",1788377988236],"branchVersion","branchId","7029bff5-bb8a-442e-a4f2-805f0156bd56","id","4a26e4ff-5701-4f0e-a2d1-9b438dea196d","ekg-rhythm-practice",["D",1788371332863],"deletedAt","legacyEnvVars","privacy","public","httpPrivacy","description","EKG rhythm interpretation practice app for nursing/EMS 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{ parseVal, serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\nimport { Hono } from \"npm:hono\";\nimport { Root } from \"./frontend/root.tsx\";\nimport { RHYTHMS } from \"./backend/rhythms-data.ts\";\nimport { TWELVE_LEAD_CASES } from \"./backend/twelve-lead-data.ts\";\n\nconst app = new Hono();\n\n// Serve the (never-cached) HTML shell at the root /\napp.get(\"/\", (c) => c.html(Root()));\n\n// Serve frontend files at the version-addressed URLs Root() stamps, cached immutably\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\n\n// View source redirect\napp.get(\"/source\", (c) => c.redirect(parseVal().links.self.val));\n\n// List all rhythms (summary only — no questions in the payload).\n// Every rhythm is unlocked content-wise; the free/Pro split is now a daily\n// practice cap enforced client-side, not a content paywall.\napp.get(\"/api/rhythms\", (c) => {\n const list = [...RHYTHMS]\n .sort((a, b) => a.sortOrder - b.sortOrder)\n .map(({ questions, ...summary }) => ({\n ...summary,\n locked: false,\n questionCount: questions.length,\n }));\n return c.json(list);\n});\n\n// Single rhythm detail — full content, including quiz questions, for everyone.\napp.get(\"/api/rhythms/:id\", (c) => {\n const rhythm = RHYTHMS.find((r) => r.id === c.req.param(\"id\"));\n if (!rhythm) return c.json({ error: \"not found\" }, 404);\n return c.json({\n ...rhythm,\n locked: false,\n });\n});\n\n// List all 12-lead cases (summary only — leadFindings + questions omitted).\napp.get(\"/api/twelve-lead\", (c) => {\n const list = [...TWELVE_LEAD_CASES]\n .sort((a, b) => a.sortOrder - b.sortOrder)\n .map(({ leadFindings, questions, ...summary }) => ({\n ...summary,\n questionCount: questions.length,\n }));\n return c.json(list);\n});\n\n// Single 12-lead case detail — full content, including per-lead findings and quiz questions.\napp.get(\"/api/twelve-lead/:id\", (c) => {\n const twelveLead = TWELVE_LEAD_CASES.find((t) => t.id === c.req.param(\"id\"));\n if (!twelveLead) return c.json({ error: \"not found\" }, 404);\n return c.json(twelveLead);\n});\n\n// Unwrap and rethrow Hono errors as the original error\n// If you delete this, all errors will be \"Internal Server Error\"\napp.onError((err) => Promise.reject(err));\n\n// HTTP vals expect an exported \"fetch handler\"\n// This is how you \"run the server\" in Val Town with Hono\nexport default app.fetch;\n","label",[138],"f174df99-6739-437c-b218-528fe54153d7","README.md","01a0633c-efa7-770e-92de-f8c87a88692d",1,["D",1788371332863],"# React + Hono Starter\n\nA minimal starter template for building client-side React apps with a Hono\nbackend on Val Town. Click **Remix** to get your own copy.\n\n## Picking a starter\n\n| Starter | When to pick it |\n| --- | --- |\n| [`basic-html-starter`](https://www.val.town/x/templates/basic-html-starter) | Static HTML pages. Sprinkle of vanilla JS. No server-side rendering. |\n| [`hono-jsx-starter`](https://www.val.town/x/templates/hono-jsx-starter) | Dynamic server-rendered HTML with JSX. API routes. No React, no SPA. |\n| **[`react-hono-starter`](https://www.val.town/x/templates/react-hono-starter)** *(you're here)* | Client-side React SPA with a Hono API backend. |\n\n**Want to build UI?** Start writing React components in\n[`frontend/components/`](/frontend/components/). Import them into `App.tsx` and\nyou're good to go. Styling is [Twind](https://twind.style/) — just use Tailwind\nutility classes, zero config.\n\n**Want to add an API?** Add routes in [`index.ts`](/index.ts) (there's a\ncommented-out example). Fetch them from your React components.\n\n## Architecture\n\n```mermaid\ngraph LR\n Browser -->|\"GET /\"| Hono[\"index.ts
(Hono server)\"]\n Hono -->|serves| HTML[\"root.tsx\"]\n HTML -->|loads| Entry[\"index.tsx\"]\n Entry -->|renders| App[\"App.tsx\"]\n App -->|renders| Counter[\"Counter.tsx\"]\n```\n\n## File structure\n\n```\nindex.ts ← Hono backend (serves frontend + API routes)\nfrontend/\n root.tsx ← HTML shell (stamps immutable asset URLs)\n index.tsx ← React entrypoint (mounts )\n favicon.svg ← App icon\n components/\n App.tsx ← Root component (layout + view source link)\n Counter.tsx ← Example component with state\n```\n\n## How it works\n\n1. **`index.ts`** is the HTTP entrypoint — a Hono server that serves the\n frontend and any API routes you add.\n2. **`frontend/root.tsx`** is the HTML shell — it loads Twind and stamps\n immutable asset URLs for the favicon and React entrypoint.\n3. **`frontend/index.tsx`** mounts the React app.\n4. **`frontend/components/App.tsx`** is the root layout — add new components\n alongside it.\n5. **`frontend/components/Counter.tsx`** is an example stateful component —\n replace it with your own!\n\n## Next steps\n\n- Add API routes in `index.ts`\n- Add new components in `frontend/components/`\n- Add a SQLite database — see the\n [React Hono Example](https://www.val.town/x/stevekrouse/reactHonoExample) for\n a full-stack example with database, queries, and shared types\n\nTemplate updates and upgrade paths for existing remixes: [CHANGELOG.md](/CHANGELOG.md)\n",[149],"4d03780d-716e-4f3b-9cdf-f3d72852a379","CHANGELOG.md","01a0633c-efa7-770e-92de-f742abd282c5",["D",1788371332863],"# Changelog\n\n## 2026-07-30 — Immutable asset caching\n\nFrontend files are now served at version-addressed URLs\n(`/__immutable/45/frontend/index.tsx`) with\n`Cache-Control: public, max-age=31536000, immutable`, so repeat visits load the\nwhole client graph from the browser cache — roughly 3× faster (~665ms → ~157ms\nmeasured). Publishing your val bumps its version, which changes every URL, so\ncaches invalidate automatically. Old-version URLs return 404 after a publish\n(like Next.js build assets); a reload picks up the new version.\n\nWhat changed in the template:\n\n- `frontend/index.html` → [`frontend/root.tsx`](/frontend/root.tsx): the HTML\n shell is now JSX and stamps asset URLs with `immutableFileUrl()`\n- [`index.ts`](/index.ts): serves `Root()` at `/`, and one\n `app.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path))` route\n serves all frontend files\n\n### Upgrading an existing remix\n\nYour copy of this template doesn't update automatically. Two options:\n\n**Minimal (most of the benefit):** point both routes at `serveImmutableFile` —\nyour existing bare URLs redirect into versioned space, the new route serves\nthem, and the whole module graph gets cached (costs one redirect per page view):\n\n```ts\nimport { serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\n\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\napp.get(\"/frontend/**/*\", (c) => serveImmutableFile(c.req.path)); // was serveFile\n```\n\n**Full upgrade (also removes the redirect):** three self-contained steps —\nno other files needed. Adjust the ``, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter\n

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