ACLS algorithms, explained the way the exam tests them

1. Card 01 / 24Cardiac arrest

   Which statement about fluid resuscitation during cardiac arrest is correct?

   1. AAll cardiac arrest patients should receive a 2L fluid bolus immediately
   2. BFluid boluses should be administered when hypovolemia is suspected as a cause
   3. CHypotonic solutions are preferred over isotonic solutions
   4. DFluid administration is contraindicated during cardiac arrest

   Explanation

   Keyed answerB. Fluid boluses should be administered when hypovolemia is suspected as a cause

   Your pickA. All cardiac arrest patients should receive a 2L fluid bolus immediately ww

   During cardiac arrest, routine fluid boluses are not recommended unless hypovolemia is suspected as a cause of the arrest. In cases where hypovolemia is a suspected cause, rapid infusion of isotonic crystalloid solution is appropriate to restore intravascular volume.

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2. Card 02 / 24Brady & tachy

   In ACLS protocols, why is it important to identify reversible causes of bradyarrhythmia such as hyperkalemia?

   1. AIt necessitates the use of high-dose beta-blockers
   2. BIt allows correction of the underlying condition without invasive procedures
   3. CIt indicates that pharmacologic therapy is unnecessary
   4. DIt confirms the need for immediate permanent pacemaker insertion

   Explanation

   Keyed answerB. It allows correction of the underlying condition without invasive procedures

   Your pickD. It confirms the need for immediate permanent pacemaker insertion ww

   Identifying reversible causes allows clinicians to correct the underlying abnormality, potentially resolving the bradyarrhythmia without the need for invasive interventions like pacing.

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3. Card 03 / 24Cardiac arrest

   Why is the administration of AV nodal blocking agents contraindicated in atrial fibrillation with rapid ventricular response in Wolff-Parkinson-White syndrome?

   1. AThey may promote conduction via the accessory pathway, increasing risk of ventricular fibrillation
   2. BThey have a prolonged half-life that causes toxicity
   3. CThey directly stimulate the accessory pathway causing arrhythmia
   4. DThey are ineffective at lowering heart rate in these patients

   Explanation

   Keyed answerA. They may promote conduction via the accessory pathway, increasing risk of ventricular fibrillation

   Your pickC. They directly stimulate the accessory pathway causing arrhythmia ww

   AV nodal blockers can preferentially block the conduction through the normal AV node, thereby promoting conduction through the accessory pathway, which may precipitate a dangerous ventricular arrhythmia.

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4. Card 04 / 24Brady & tachy

   In an elderly patient with bradycardia and a prolonged PR interval, what additional diagnostic modality can help uncover intermittent high-grade AV block?

   1. ACarotid duplex ultrasound
   2. BSerum electrolyte testing alone
   3. CImmediate CT scan of the chest
   4. DHolter monitoring

   Explanation

   Keyed answerD. Holter monitoring

   Your pickB. Serum electrolyte testing alone ww

   Holter monitoring provides continuous ECG recording over an extended period, which can reveal intermittent episodes of high-grade AV block not seen on a single ECG.

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5. Card 05 / 24Cardiac arrest

   Within the context of ACLS, when should antiarrhythmic agents like amiodarone be administered?

   1. AAs the first-line agent in non-shockable rhythms.
   2. BBefore any defibrillation attempts are made.
   3. COnly during post-resuscitation care after ROSC.
   4. DAfter defibrillation and epinephrine in refractory shockable rhythms.

   Explanation

   Keyed answerD. After defibrillation and epinephrine in refractory shockable rhythms.

   Your pickA. As the first-line agent in non-shockable rhythms. ww

   They are indicated after defibrillation and epinephrine in refractory shockable rhythms, according to ACLS protocols.

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6. Card 06 / 24Brady & tachy

   Which of the following is the most appropriate pharmacological treatment for hemodynamically stable atrial fibrillation with rapid ventricular response in a patient with preserved ejection fraction?

   1. AAdenosine
   2. BMetoprolol
   3. CEpinephrine
   4. DAmiodarone

   Explanation

   Keyed answerB. Metoprolol

   Your pickC. Epinephrine ww

   For stable atrial fibrillation with rapid ventricular response in patients with preserved ejection fraction, a beta-blocker like metoprolol is recommended to control the ventricular rate.

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7. Card 07 / 24Cardiac arrest

   How does integrating pharmacologic strategies with timely defibrillation optimize outcomes in refractory ventricular arrhythmias?

   1. AMedications should replace defibrillation in all refractory cases.
   2. BDrugs are administered only after all defibrillation attempts fail without coordination.
   3. CPharmacologic strategies delay defibrillation and worsen outcomes.
   4. DTimely medication administration combined with defibrillation helps terminate refractory arrhythmias.

   Explanation

   Keyed answerD. Timely medication administration combined with defibrillation helps terminate refractory arrhythmias.

   Your pickB. Drugs are administered only after all defibrillation attempts fail without coordination. ww

   Sequential and coordinated interventions increase the likelihood of rhythm conversion by addressing both the electrical and biochemical aspects of arrest.

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8. Card 08 / 24Brady & tachy

   Which medication would be most appropriate for chemical cardioversion of new-onset atrial fibrillation in a patient with hypertrophic cardiomyopathy?

   1. AMetoprolol
   2. BAmiodarone
   3. CVerapamil
   4. DDiltiazem

   Explanation

   Keyed answerB. Amiodarone

   Your pickA. Metoprolol ww

   Amiodarone is the preferred agent for chemical cardioversion in patients with hypertrophic cardiomyopathy as it has less negative inotropic effect compared to other antiarrhythmics. It also avoids the potential for increased outflow tract obstruction that can occur with some other agents.

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9. Card 09 / 24Cardiac arrest

   Which of the following is a 'H' in the 'Hs and Ts' of potentially reversible causes of cardiac arrest?

   1. AHypercoagulability
   2. BHypovolemia
   3. CHyperventilation
   4. DHeart block

   Explanation

   Keyed answerB. Hypovolemia

   Your pickA. Hypercoagulability ww

   Hypovolemia is one of the 'H's in the 'Hs and Ts' mnemonic for potentially reversible causes of cardiac arrest. The 'H's include Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, and Hypothermia.

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10. Card 10 / 24Brady & tachy

    What is the maximum total dose of atropine recommended for treating bradycardia in adults?

    1. A6 mg
    2. B1 mg
    3. C3 mg
    4. D12 mg

    Explanation

    Keyed answerC. 3 mg

    Your pickD. 12 mg ww

    The maximum total dose of atropine for treating bradycardia in adults is 3 mg. Doses above this level are unlikely to produce additional beneficial chronotropic effects.

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11. Card 11 / 24Cardiac arrest

    What is the recommended dose of calcium chloride for a patient with hyperkalemia-induced cardiac arrest?

    1. A10 mL of 10% solution (1 gram) IV/IO
    2. B5 mL of 10% solution (0.5 gram) IV/IO
    3. C1 mL of 10% solution (0.1 gram) IV/IO
    4. D20 mL of 10% solution (2 grams) IV/IO

    Explanation

    Keyed answerA. 10 mL of 10% solution (1 gram) IV/IO

    Your pickB. 5 mL of 10% solution (0.5 gram) IV/IO ww

    When calcium chloride is given for suspected hyperkalemia in cardiac arrest, the usual dose is 10 mL of a 10% solution (1 gram) IV/IO; calcium antagonizes the cardiac effects of a high potassium. Note that the 2025 AHA Guidelines describe the effectiveness of calcium in hyperkalemic cardiac arrest as not well established, and routine calcium in arrest is not recommended. High-quality CPR, defibrillation when indicated and treating the cause come first.

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12. Card 12 / 24Brady & tachy

    What is the appropriate initial management for a 68-year-old patient presenting with new onset atrial fibrillation with a ventricular rate of 160 bpm and normal blood pressure?

    1. AAdministration of IV amiodarone for immediate rhythm control
    2. BAnticoagulation only without rate control
    3. CRate control with IV diltiazem or metoprolol
    4. DImmediate electrical cardioversion

    Explanation

    Keyed answerC. Rate control with IV diltiazem or metoprolol

    Your pickA. Administration of IV amiodarone for immediate rhythm control ww

    For a hemodynamically stable patient with new-onset atrial fibrillation and rapid ventricular response, the initial approach is rate control with AV nodal blocking agents. IV diltiazem or beta-blockers like metoprolol are appropriate first-line medications to slow the ventricular rate.

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13. Card 13 / 24Cardiac arrest

    Which antiarrhythmic medication is recommended for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia after the third shock?

    1. ALidocaine 100 mg IV/IO
    2. BAtropine 1 mg IV/IO
    3. CProcainamide 30 mg/min IV/IO
    4. DAmiodarone 300 mg IV/IO

    Explanation

    Keyed answerD. Amiodarone 300 mg IV/IO

    Your pickC. Procainamide 30 mg/min IV/IO ww

    Amiodarone is the recommended antiarrhythmic medication for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia. The initial dose is 300 mg IV/IO bolus, with a second dose of 150 mg if needed.

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14. Card 14 / 24Brady & tachy

    Which finding on a 12-lead ECG best differentiates atrial flutter from other supraventricular tachycardias?

    1. APresence of delta waves
    2. BRegular narrow QRS complexes without visible P waves
    3. CSaw-tooth flutter waves in leads II, III, and aVF
    4. DST-segment elevation in precordial leads

    Explanation

    Keyed answerC. Saw-tooth flutter waves in leads II, III, and aVF

    Your pickB. Regular narrow QRS complexes without visible P waves ww

    Atrial flutter typically presents with characteristic saw-tooth flutter waves (F waves) in the inferior leads (II, III, aVF), which represent rapid regular atrial activity at a rate of 250-350 bpm. This distinctive pattern helps differentiate atrial flutter from other supraventricular tachycardias.

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15. Card 15 / 24Cardiac arrest

    What is a key consideration when interpreting end-tidal CO2 (ETCO2) values during cardiac arrest?

    1. AValues only reflect lung function, not circulation quality
    2. BValues should always be maintained above 35 mmHg during CPR
    3. CPersistently low values often indicate poor cardiac output from inadequate CPR quality
    4. DETCO2 has no correlation with cardiac output during arrest

    Explanation

    Keyed answerC. Persistently low values often indicate poor cardiac output from inadequate CPR quality

    Your pickB. Values should always be maintained above 35 mmHg during CPR ww

    Persistently low ETCO2 during CPR usually means little blood is reaching the lungs, which most often points to poor compression quality. ETCO2 works as a real-time marker of CPR effectiveness: better compressions should raise it, and an abrupt, sustained rise can be a sign of return of spontaneous circulation (ROSC). The 2025 chart shows the trend without a number; the Guidelines text treats at least 10 mm Hg, ideally 20, as a sign the compressions are working.

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16. Card 16 / 24Brady & tachy

    What is the most appropriate initial management for a patient with a narrow-complex tachycardia at 170 bpm who is complaining of mild palpitations but has stable vital signs?

    1. AImmediate synchronized cardioversion
    2. BDefibrillation at 200 J
    3. CIV amiodarone administration
    4. DVagal maneuvers (e.g., Valsalva)

    Explanation

    Keyed answerD. Vagal maneuvers (e.g., Valsalva)

    Your pickA. Immediate synchronized cardioversion ww

    For stable patients with narrow-complex tachycardia, vagal maneuvers are the recommended first step in management before proceeding to pharmacological interventions. These non-invasive techniques may terminate the arrhythmia by increasing parasympathetic tone.

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17. Card 17 / 24Cardiac arrest

    Which of the following is the correct dose of sodium bicarbonate for a patient with prolonged cardiac arrest and suspected metabolic acidosis?

    1. A2 mEq/kg IV
    2. B0.5 mEq/kg IV
    3. C1 mEq/kg IV
    4. D50 mEq flat dose for all adults

    Explanation

    Keyed answerC. 1 mEq/kg IV

    Your pickD. 50 mEq flat dose for all adults ww

    For patients with prolonged cardiac arrest and suspected metabolic acidosis, sodium bicarbonate can be considered at a dose of 1 mEq/kg IV. It is not routinely recommended in cardiac arrest but may be considered in specific situations like known preexisting hyperkalemia, tricyclic antidepressant overdose, or prolonged resuscitation with severe acidosis.

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18. Card 18 / 24Brady & tachy

    Which of the following medications can potentially exacerbate bradycardia and should be considered as a possible cause in patients presenting with symptomatic bradycardia?

    1. ABeta-blockers (e.g., metoprolol)
    2. BACE inhibitors (e.g., lisinopril)
    3. CDiuretics (e.g., furosemide)
    4. DStatins (e.g., atorvastatin)

    Explanation

    Keyed answerA. Beta-blockers (e.g., metoprolol)

    Your pickB. ACE inhibitors (e.g., lisinopril) ww

    Beta-blockers like metoprolol can cause or exacerbate bradycardia by blocking beta-adrenergic receptors in the heart, reducing the influence of sympathetic stimulation on heart rate and conduction. Identifying and holding these medications is an important part of bradycardia management.

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19. Card 19 / 24Cardiac arrest

    What is the maximum number of defibrillation attempts recommended before initiating CPR in witnessed VF cardiac arrest?

    1. AAs many as needed until a perfusing rhythm is restored
    2. BOne defibrillation attempt
    3. CThree consecutive defibrillation attempts
    4. DTwo defibrillation attempts at escalating energy

    Explanation

    Keyed answerB. One defibrillation attempt

    Your pickA. As many as needed until a perfusing rhythm is restored ww

    In witnessed VF cardiac arrest, one immediate defibrillation attempt is recommended before initiating CPR. After the initial shock, CPR should be performed for 2 minutes before reassessing the rhythm and potentially delivering additional shocks.

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20. Card 20 / 24Brady & tachy

    Which medication should be considered for rate control in atrial fibrillation for a patient with decompensated heart failure?

    1. ADiltiazem
    2. BVerapamil
    3. CMetoprolol
    4. DDigoxin

    Explanation

    Keyed answerD. Digoxin

    Your pickC. Metoprolol ww

    Digoxin is appropriate for rate control in atrial fibrillation in patients with decompensated heart failure as it doesn't have the negative inotropic effects that many other rate-controlling agents have, though its onset is slower than other options.

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21. Card 21 / 24Cardiac arrest

    When should the first shock be delivered to a cardiac arrest victim found in a shockable rhythm?

    1. AAs soon as the AED/defibrillator is ready
    2. BAfter administering the first dose of epinephrine
    3. CAfter 2 minutes of CPR
    4. DAfter establishing IV access

    Explanation

    Keyed answerA. As soon as the AED/defibrillator is ready

    Your pickB. After administering the first dose of epinephrine ww

    The first shock should be delivered as soon as the AED or defibrillator is ready. Early defibrillation for shockable rhythms is critical for survival, as the chances of successful defibrillation decrease with time.

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22. Card 22 / 24Brady & tachy

    Which of the following is a correct pairing of bradyarrhythmia and its appropriate pharmacological treatment?

    1. ASymptomatic sinus bradycardia — Atropine
    2. BAsymptomatic sinus bradycardia — Epinephrine infusion
    3. CSymptomatic third-degree AV block — Calcium channel blocker
    4. DMobitz type II second-degree AV block — Isoproterenol bolus

    Explanation

    Keyed answerA. Symptomatic sinus bradycardia — Atropine

    Your pickC. Symptomatic third-degree AV block — Calcium channel blocker ww

    Symptomatic sinus bradycardia is appropriately treated with atropine, which blocks parasympathetic (vagal) effects on the SA node, increasing the heart rate. Atropine is the first-line pharmacological treatment for symptomatic bradycardia according to ACLS guidelines.

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23. Card 23 / 24Cardiac arrest

    According to ACLS guidelines, what is the recommended approach for a patient with refractory VF/pVT after standard treatment?

    1. AAdminister increasingly higher doses of epinephrine beyond standard protocol
    2. BImmediately terminate resuscitation efforts after three defibrillation attempts
    3. CConsider advanced interventions such as double sequential defibrillation, ECPR, or emergent PCI if available
    4. DPerform immediate thoracotomy in all cases

    Explanation

    Keyed answerC. Consider advanced interventions such as double sequential defibrillation, ECPR, or emergent PCI if available

    Your pickB. Immediately terminate resuscitation efforts after three defibrillation attempts ww

    For VF/pVT that persists after standard treatment (defibrillation, CPR, epinephrine and an antiarrhythmic), the 2025 Guidelines say the usefulness of double sequential or vector-change defibrillation is not established, so it may be considered but is not routine; extracorporeal CPR (ECPR) where available and PCI for a suspected cardiac cause are the other options. Escalating epinephrine, stopping after three shocks and routine thoracotomy are not part of the algorithm.

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24. Card 24 / 24Brady & tachy

    A 45-year-old patient presents with sudden onset of regular narrow-complex tachycardia at 220 bpm. After two doses of adenosine failed to convert the rhythm, what is the most appropriate next step?

    1. AAdminister IV diltiazem
    2. BAdminister a higher dose of adenosine (18 mg)
    3. CAdminister IV amiodarone
    4. DProceed directly to electrical cardioversion

    Explanation

    Keyed answerA. Administer IV diltiazem

    Your pickB. Administer a higher dose of adenosine (18 mg) ww

    After failed adenosine attempts for narrow-complex tachycardia, the next step is typically a longer-acting AV nodal blocking agent or an antiarrhythmic medication. IV diltiazem is appropriate for ongoing rate control in a hemodynamically stable patient with SVT that was refractory to adenosine.

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25. Score card

    0%

    Answer a few cards and come back to this one.

    • Cardiac arrestnot yet
    • Brady & tachynot yet

    The thin line on each bar marks 84%, the written-exam pass mark AHA Training Centers usually quote; your instructor confirms the exact rule.

    Shuffle back to card 1

Pick an answer and the card turns over to the explanation. Keys: A to D or 1 to 4, arrows to move, F to turn the card.