MegacodeBeginner
Witnessed VF Arrest
A 62-year-old man clutches his chest in the ED waiting room and collapses. You are the first responder.
cardiac-arrest6 stepsRecognize shockable VF and defibrillate promptlyCycle CPR → shock → drugs correctly
Case Library
Every rhythm and megacode scenario in one place — filter by tag or difficulty and start instantly. Add your own scenarios too.
24 of 24
MegacodeIntermediate
Asystole in the ICU
A 78-year-old ICU patient with sepsis suddenly loses her monitor waveform. You are the code leader.
cardiac-arrest4 stepsConfirm asystole is not artifact or fine VFManage a non-shockable arrest
MegacodeAdvanced
PEA after Surgery
POD 3 after knee replacement, a 65-year-old woman suddenly becomes unresponsive. Monitor shows a narrow-complex organized rhythm at 110 but you cannot palpate a pulse.
cardiac-arrest3 stepsDistinguish PEA from a perfusing rhythmIdentify pulmonary embolism as a reversible cause
MegacodeIntermediate
Unstable Bradycardia (Complete Heart Block)
An 80-year-old man presents with light-headedness and a syncopal episode. HR 32, BP 78/40, cool and clammy.
bradycardia3 stepsRecognize unstable bradycardiaApply the bradycardia algorithm
MegacodeIntermediate
Unstable SVT
A 45-year-old woman presents with palpitations, chest pressure, and near-syncope. HR 210, BP 78/45.
tachycardia2 stepsRecognize unstable narrow-complex tachycardiaPerform synchronized cardioversion
MegacodeAdvanced
Torsades de Pointes
A 55-year-old on IV haloperidol and levofloxacin becomes unresponsive. Monitor shows polymorphic wide-complex tachycardia with a twisting axis.
cardiac-arrest2 stepsRecognize torsadesGive magnesium
RhythmBeginner
Normal Sinus Rhythm
The heart's baseline rhythm: SA node fires regularly, every P wave is followed by a QRS.
NormalNon-shockableRate 60–100
RhythmBeginner
Sinus Bradycardia
Sinus rhythm at a rate below 60 bpm.
NormalNon-shockableRate < 60bradycardia
RhythmBeginner
Sinus Tachycardia
Sinus rhythm above 100 bpm — usually a response to an underlying cause.
NormalNon-shockableRate > 100
RhythmIntermediate
Atrial Fibrillation
Chaotic atrial activity with irregularly irregular ventricular response and no discrete P waves.
AtrialNon-shockableRate Variabletachycardia
RhythmIntermediate
Atrial Flutter
Sawtooth flutter waves from a re-entrant atrial circuit (~300/min), usually with 2:1 AV conduction.
AtrialNon-shockableRate 150 (2:1)tachycardia
RhythmIntermediate
Supraventricular Tachycardia
Narrow-complex regular tachycardia originating above the ventricles.
AtrialNon-shockableRate 150–220tachycardia
RhythmIntermediate
Monomorphic Ventricular Tachycardia
Wide-complex regular tachycardia from a single ventricular focus.
VentricularShockableRate 150–250cardiac-arrest
RhythmIntermediate
Polymorphic VT / Torsades de Pointes
Twisting-axis polymorphic VT, often associated with prolonged QT.
VentricularShockableRate 200–250cardiac-arrest
RhythmAdvanced
Coarse Ventricular Fibrillation
Chaotic, disorganized ventricular activity — no cardiac output. Shockable.
ArrestShockableRate N/Acardiac-arrest
RhythmAdvanced
Fine Ventricular Fibrillation
Low-amplitude VF — easy to mistake for asystole. Still shockable.
ArrestShockableRate N/Acardiac-arrest
RhythmAdvanced
Asystole
Absence of electrical activity — flat line. NOT shockable.
ArrestNon-shockableRate 0cardiac-arrest
RhythmAdvanced
Pulseless Electrical Activity (PEA)
Any organized rhythm on the monitor with NO palpable pulse. Rhythm looks normal — patient is in arrest.
ArrestNon-shockableRate Any organizedcardiac-arrest
RhythmAdvanced
1st Degree AV Block
Every P conducted, but PR > 200 ms. Usually benign.
BlockNon-shockableRate Underlying
RhythmAdvanced
2nd Degree AV Block, Mobitz I (Wenckebach)
Progressive PR lengthening until a QRS is dropped.
BlockNon-shockableRate Underlyingbradycardia
RhythmAdvanced
2nd Degree AV Block, Mobitz II
Constant PR with sudden dropped QRS. High risk of progressing to complete block.
BlockNon-shockableRate Underlyingbradycardia
RhythmAdvanced
3rd Degree (Complete) AV Block
Complete AV dissociation — atria and ventricles fire independently.
BlockNon-shockableRate 30–45bradycardia
RhythmIntermediate
Idioventricular Rhythm
Slow, wide ventricular escape rhythm.
VentricularNon-shockableRate 20–40bradycardia
RhythmAdvanced
Agonal Rhythm
Very slow, wide, dying complexes. Peri-arrest.
ArrestNon-shockableRate < 20cardiac-arrest