Management of Ventricular Arrhythmias and Sudden Cardiac Arrest: Part 1

56 question(s) with answers and explanations.

Question 1

A 68-year-old male with a history of ischemic cardiomyopathy presents to the emergency department with sustained wide complex tachycardia at a rate of 180 bpm. He is hypotensive, with a blood pressure of 80/60 mmHg. An ECG shows a monomorphic ventricular tachycardia (VT). Initial attempts at intravenous amiodarone administration are unsuccessful, and the VT persists despite the infusion. The patient's condition continues to deteriorate. What is the next most appropriate step in management?

• ○ Administer intravenous verapamil to control the ventricular rate.
• ✓ Perform immediate electrical cardioversion.
• ○ Initiate a procainamide infusion.
• ○ Attempt overdrive pacing to suppress the VT.

Explanation. Given the patient's hemodynamic instability (hypotension) and persistent ventricular tachycardia despite antiarrhythmic medication, immediate electrical cardioversion is the most appropriate next step. The text emphasizes prompt differentiation between potentially lethal and non-lethal arrhythmias, and in this case, the patient's condition is rapidly deteriorating, necessitating immediate intervention.

Question 2

A 62-year-old male with a history of a prior anterior ST-elevation myocardial infarction (STEMI) presents to the emergency department with palpitations and lightheadedness. His ECG shows a wide QRS complex tachycardia at a rate of 180 bpm. He is hemodynamically stable. What is the most appropriate initial step in the management of this patient?

• ✓ Amiodarone infusion
• ○ Electrical cardioversion
• ○ Lidocaine bolus followed by infusion
• ○ Procainamide infusion

Explanation. In the acute treatment of sustained ventricular arrhythmias, amiodarone is an appropriate initial antiarrhythmic agent for a hemodynamically stable patient with wide QRS complex tachycardia.

Question 3

A 68-year-old male with a history of ischemic cardiomyopathy presents to the emergency department with palpitations and lightheadedness. His ECG shows a wide complex tachycardia at a rate of 180 bpm. The patient's blood pressure is 80/60 mmHg. The arrhythmia is sustained and unresponsive to vagal maneuvers. What is the most important next step in the management of this patient?

• ○ Administration of intravenous amiodarone.
• ✓ Synchronized cardioversion.
• ○ Administration of intravenous adenosine.
• ○ Obtain a detailed history to assess the duration and frequency of the arrhythmia.

Explanation. Given the patient's hemodynamic instability (hypotension) in the setting of a wide complex tachycardia, synchronized cardioversion is the most appropriate and immediate next step to restore adequate cardiac output and blood pressure.

Question 4

A 62-year-old male with a history of hypertension and hyperlipidemia presents to the emergency department complaining of palpitations and near-syncope. He is diaphoretic and anxious. His initial heart rate is 180 bpm. The ECG shows a wide complex tachycardia with continuously changing QRS complex morphology and no clear isoelectric baseline between the QRS complexes. What is the most likely diagnosis?

• ○ Monomorphic ventricular tachycardia (VT)
• ✓ Polymorphic ventricular tachycardia (VT)
• ○ Torsades de pointes (TdP)
• ○ Atrial fibrillation with aberrant conduction

Explanation. The ECG description of continuously changing QRS complex morphology with no clear isoelectric baseline between the QRS complexes is consistent with polymorphic VT.

Question 5

A 62-year-old male presents to the emergency department with palpitations and lightheadedness. An ECG reveals a wide-complex tachycardia with a rate of 180 bpm. The QRS complexes demonstrate a right bundle branch block (RBBB) morphology. The rhythm spontaneously terminates after 25 seconds, and the patient's symptoms resolve. An extensive cardiac workup, including echocardiography and cardiac MRI, reveals no structural heart disease or evidence of an inherited ion channel disorder. What is the most likely classification of this patient's ventricular tachycardia (VT)?

• ○ Incessant VT
• ○ Sustained VT
• ✓ Non-sustained VT
• ○ Accelerated idioventricular rhythm (AIVR)

Explanation. Non-sustained VT is defined as ≥3 complexes, >100 bpm, terminating spontaneously. The patient's VT lasted for 25 seconds and terminated spontaneously, fitting the definition of non-sustained VT. The absence of structural heart disease suggests that the VT is idiopathic.

Question 6

A 32-year-old female presents to the clinic complaining of palpitations and occasional lightheadedness, particularly during exercise. An ECG reveals a wide complex tachycardia with a left bundle branch block (LBBB) morphology, inferior axis, and transition in leads V3-V4. Which of the following is the most likely origin of the ventricular tachycardia (VT)?

• ○ Mitral annular region
• ○ Left ventricular (LV) fascicle
• ✓ Right ventricular outflow tract (RVOT)
• ○ Papillary muscles

Explanation. The ECG findings of LBBB morphology, inferior axis, and transition in V3-V4 are characteristic of ventricular arrhythmias originating in the right ventricular outflow tract (RVOT).

Question 7

A 25-year-old male collapses during a basketball game. He is successfully resuscitated after experiencing ventricular fibrillation (VF). His past medical history is unremarkable, and he denies any family history of sudden cardiac death. An ECG reveals a prolonged QTc interval. Genetic testing is positive for a mutation associated with abnormal cardiac ion channel function. Which of the following inherited arrhythmia syndromes is most likely responsible for this patient's presentation?

• ○ Brugada syndrome
• ○ Catecholaminergic polymorphic ventricular tachycardia (CPVT)
• ✓ Long QT syndrome (LQTS)
• ○ Arrhythmogenic right ventricular cardiomyopathy (ARVC)

Explanation. The patient's presentation with ventricular fibrillation (VF) during exercise, a prolonged QTc interval on ECG, and a confirmed genetic mutation associated with abnormal cardiac ion channel function are all characteristic features of long QT syndrome (LQTS). LQTS is known to present as polymorphic ventricular tachycardia (VT) or VF.

Question 8

A 62-year-old male with a history of a prior myocardial infarction presents to the emergency department with sustained monomorphic ventricular tachycardia (VT). He is hemodynamically stable. An ECG during VT shows a QRS duration of 160 ms with a left bundle branch block (LBBB) morphology and a QS complex in V1. Coronary angiography reveals non-obstructive coronary artery disease (CAD). Which of the following features on the VT ECG tracing would further increase the likelihood that the VT is scar-related?

• ✓ Absence of an R/S pattern in precordial leads.
• ○ R wave to S wave nadir duration of 40 ms in V2.
• ○ Frontal plane axis of +120 degrees.
• ○ Presence of an R wave in V1.

Explanation. The absence of an R/S pattern in precordial leads supports the diagnosis of scar-related VT in the setting of structural heart disease.

Question 9

A 68-year-old male with a history of prior myocardial infarction presents to the emergency department with palpitations and near-syncope. His ECG shows a wide QRS complex tachycardia at a rate of 180 bpm. All precordial leads (V1-V6) show positive deflections. What is the most likely diagnosis?

• ○ Atrial fibrillation with aberrancy
• ✓ Ventricular tachycardia
• ○ Supraventricular tachycardia (SVT) with pre-excitation
• ○ Atrial flutter with bundle branch block (BBB)

Explanation. The presence of 'concordance' in the precordial leads, where all leads show either positive or negative deflections during a wide QRS complex tachycardia, is highly suggestive of ventricular tachycardia (VT).

Question 10

A 68-year-old male with a history of hypertension and no prior documented arrhythmias presents to the emergency department with palpitations and dizziness. An ECG reveals a wide QRS complex tachycardia at a rate of 180 bpm. The QRS morphology resembles a right bundle branch block (RBBB) pattern. The patient states he has never been told he has RBBB before. Which of the following is the MOST likely origin of the patient's wide complex tachycardia?

• ○ Supraventricular tachycardia (SVT) with pre-existing RBBB.
• ✓ Ventricular tachycardia (VT).
• ○ Atrial fibrillation with rate-related aberration.
• ○ Antidromic atrioventricular reentrant tachycardia (AVRT) utilizing an accessory pathway.

Explanation. The presence of a bundle branch block pattern different from a previously documented bundle branch block strongly suggests underlying structural heart disease and a ventricular origin of the arrhythmia. In this case, the patient is not known to have RBBB, but the current wide complex tachycardia has RBBB morphology, making VT the most likely diagnosis.

Question 11

A 28-year-old male with Wolff-Parkinson-White (WPW) syndrome presents to the emergency department in atrial fibrillation. His ECG shows a rapid, irregular wide-complex tachycardia. Which of the following medications is most likely to exacerbate his condition and potentially lead to ventricular fibrillation?

• ✓ Intravenous amiodarone
• ○ Intravenous procainamide
• ○ Intravenous metoprolol
• ○ Intravenous diltiazem

Explanation. In atrial fibrillation with pre-excitation, a short refractory period of the accessory pathway allows fast conduction of the atrial fibrillatory waves to the ventricles, and this may result in ventricular fibrillation. Antiarrhythmic drugs (AADs) such as amiodarone can enhance conduction over the accessory pathway, increasing the risk of ventricular fibrillation.

Question 12

A 72-year-old male with a history of ischemic cardiomyopathy and a dual-chamber pacemaker presents to the emergency department with palpitations and shortness of breath. His ECG shows a wide QRS complex tachycardia at a rate of 160 bpm. Pacing spikes are visible preceding each QRS complex. The QRS morphology demonstrates a left bundle branch block (LBBB) pattern with a concordant negative pattern in the precordial leads and a superior axis. Given this ECG presentation, which of the following is the most likely location of the ventricular pacing lead?

• ○ Left ventricular (LV) free wall
• ✓ Right ventricular (RV) apex
• ○ Right ventricular (RV) septum
• ○ Left bundle branch area pacing (LBBAP)

Explanation. In a conventional dual-chamber pacemaker with RV apical pacing, the QRS complexes during ventricular pacing usually have an LBBB morphology with a concordant negative pattern in the precordial leads and a superior axis.

Question 13

A 68-year-old male presents to the emergency department with a wide complex tachycardia at a rate of 180 bpm. He has a history of hypertension and stable angina. An ECG shows a QRS duration of 150 ms with a right bundle branch block (RBBB) morphology. Carotid sinus massage is performed without effect. Which of the following is the most likely diagnosis?

• ○ Atrial fibrillation with aberrant conduction
• ✓ Ventricular tachycardia (VT)
• ○ Supraventricular tachycardia (SVT) with aberrant conduction
• ○ Sinus tachycardia with RBBB

Explanation. The patient has a wide complex tachycardia with a QRS duration of 150 ms and RBBB morphology. A QRS duration >140 ms in the setting of RBBB morphology favors VT. While SVT with aberrant conduction is a possibility, the QRS duration makes VT more likely.

Question 14

A 68-year-old male with a history of hypertension and a prior myocardial infarction is brought to the emergency department with palpitations and lightheadedness. His ECG shows a wide complex tachycardia at a rate of 180 bpm. The QRS morphology in V1 exhibits an rSR' pattern. Which of the following features would favor a diagnosis of ventricular tachycardia (VT) over supraventricular tachycardia (SVT) with aberrancy?

• ○ QRS duration of 110 ms.
• ○ Absence of AV dissociation enhanced by carotid sinus pressure.
• ✓ QRS axis between -90 and -180 degrees.
• ○ Presence of fusion beats.

Explanation. A QRS axis between -90 and 180 degrees (superior axis) favors VT. This axis deviation does not typically occur with left bundle branch block (LBBB) or right bundle branch block (RBBB) patterns, suggesting a ventricular origin of the tachycardia.

Question 15

A 68-year-old male presents to the emergency department with palpitations and lightheadedness. An ECG reveals a wide complex tachycardia with a rate of 180 bpm. The QRS complex in lead V6 demonstrates a deep S wave, and the R/S ratio is < 1. There is a left axis deviation present. What is the most likely diagnosis?

• ○ Sinus tachycardia with aberrancy
• ○ Supraventricular tachycardia (SVT) with left bundle branch block (LBBB)
• ✓ Ventricular tachycardia (VT)
• ○ Atrial fibrillation with pre-excitation

Explanation. In the presence of left axis deviation, a deep S wave in V6 with an R/S ratio less than 1 supports the diagnosis of ventricular tachycardia (VT).

Question 16

A 68-year-old male with a history of prior myocardial infarction presents to the emergency department with a wide complex tachycardia at a rate of 180 bpm. An ECG reveals a QRS complex in lead aVR with an initial r wave lasting 50 ms. Based on the aVR Vereckei algorithm, what is the most likely diagnosis?

• ○ Supraventricular tachycardia with aberrant conduction
• ✓ Ventricular tachycardia
• ○ Atrial fibrillation with Wolf-Parkinson-White syndrome
• ○ Sinus tachycardia with bundle branch block

Explanation. According to the Vereckei algorithm, the presence of an initial r wave in lead aVR with a duration greater than 40 ms suggests a diagnosis of ventricular tachycardia.

Question 17

A 68-year-old male with a history of ischemic cardiomyopathy and a left ventricular ejection fraction (LVEF) of 30% presents to the emergency department with wide-complex tachycardia at a rate of 180 bpm. He is hypotensive with a blood pressure of 80/60 mmHg. The ECG shows a wide QRS complex with a morphology that could represent either supraventricular tachycardia (SVT) with aberrancy or ventricular tachycardia (VT). What is the most appropriate initial management strategy?

• ○ Administer intravenous verapamil for presumed SVT.
• ✓ Administer intravenous amiodarone for presumed VT.
• ○ Perform a carotid sinus massage to attempt to terminate the tachycardia.
• ○ Administer intravenous diltiazem for presumed SVT.

Explanation. In a patient with structural heart disease, reduced LVEF, and wide-complex tachycardia, differentiating between SVT with aberration and VT based on ECG criteria alone can be unreliable. Given the potential for hemodynamic instability and the risk associated with misdiagnosing VT as SVT, it is safest to treat the tachycardia as VT. Amiodarone is an appropriate antiarrhythmic for VT in this setting.

Question 18

A 68-year-old male presents to the emergency department with a wide complex tachycardia. He is hypotensive with a blood pressure of 70/40 mmHg and complaining of severe chest pain. An ECG confirms monomorphic ventricular tachycardia (VT). The patient is immediately prepared for electrical cardioversion. Which of the following is the MOST appropriate initial step in the cardioversion procedure?

• ○ Administer an unsynchronized shock of 100 J using a monophasic defibrillator.
• ○ Administer amiodarone 150mg IV push over 10 minutes.
• ✓ Sedate the patient and deliver a synchronized shock of 200 J using a biphasic defibrillator.
• ○ Attempt vagal maneuvers and observe for response.

Explanation. Given the patient's hemodynamic instability (hypotension, chest pain) and monomorphic VT, immediate synchronized cardioversion is indicated. The text states that signs of hemodynamic compromise with hypotension and angina warrant immediate sedation and synchronous DC cardioversion in monomorphic VT. It is recommended to always use the biphasic DC shock mode, and the minimum energy output in the biphasic shock configuration should not be <150-200 J.

Question 19

A 62-year-old male presents to the emergency department with palpitations and dizziness. An electrocardiogram (ECG) reveals a wide-complex tachycardia at a rate of 180 bpm. The patient is currently alert and has a blood pressure of 110/70 mmHg. He denies chest pain or shortness of breath. He has a history of hypertension, well-controlled with medication. Which of the following is the MOST important next step in the management of this patient?

• ○ Administer intravenous amiodarone.
• ○ Perform a carotid sinus massage.
• ✓ Obtain a detailed history and prior ECGs to determine the origin and mechanism of the tachycardia.
• ○ Immediately proceed with synchronized cardioversion.

Explanation. Documenting the tachycardia is crucial for identifying the correct diagnosis, including its origin and possible mechanism. This will lead to appropriate long-term treatment strategies. While the patient is stable, determining the underlying cause of the wide-complex tachycardia is paramount.

Question 20

A 62-year-old male with a history of hypertension and a prior myocardial infarction presents to the emergency department with palpitations and lightheadedness. An ECG reveals a wide QRS complex tachycardia at a rate of 180 bpm. He is currently conscious and has stable blood pressure. After confirming the diagnosis of ventricular tachycardia (VT), which of the following is the MOST appropriate initial treatment?

• ○ Intravenous lidocaine
• ✓ Synchronized electrical cardioversion after appropriate sedation
• ○ Intravenous verapamil
• ○ Intravenous beta-blocker

Explanation. For hemodynamically stable patients diagnosed with ventricular tachycardia (VT), the first-line treatment is synchronized electrical cardioversion after appropriate sedation.

Question 21

A 62-year-old male with a history of coronary artery disease presents to the emergency department after experiencing syncope. An ECG reveals sustained polymorphic ventricular tachycardia (VT) with a prolonged QT interval. Initial laboratory results show a potassium level of 3.2 mEq/L (normal: 3.5-5.0 mEq/L) and a magnesium level of 1.5 mg/dL (normal: 1.7-2.2 mg/dL). Which of the following is the MOST appropriate initial management step?

• ○ Administer intravenous amiodarone.
• ✓ Perform immediate electrical cardioversion.
• ○ Infuse intravenous verapamil.
• ○ Initiate beta-blocker therapy.

Explanation. Patients with sustained Torsades de Pointes (TdP) VT should be cardioverted.

Question 22

A 62-year-old male with a history of a prior myocardial infarction (MI) and an ejection fraction of 30% presents to the emergency department with symptomatic ventricular tachycardia (VT). Which of the following antiarrhythmic drugs (AADs) is contraindicated in this patient?

• ○ Lidocaine
• ○ Amiodarone
• ✓ Flecainide
• ○ Mexiletine

Explanation. Flecainide, a Class IC AAD, is contraindicated in patients with depressed left ventricular (LV) function, especially in the setting of a previous MI, because it is associated with increased all-cause mortality and arrhythmic death.

Question 23

A 45-year-old male with Brugada syndrome experiences an episode of ventricular fibrillation (VF) storm despite optimal implantable cardioverter-defibrillator (ICD) programming. After successful resuscitation, which of the following antiarrhythmic medications is MOST appropriate for chronic oral treatment to prevent recurrent VF episodes?

• ○ Amiodarone
• ○ Sotalol
• ✓ Quinidine
• ○ Lidocaine

Explanation. Quinidine has proven to be invaluable in the setting of ventricular tachycardia (VT)/VF storm and subsequent chronic oral treatment in patients with Brugada syndrome.

Question 24

A 68-year-old male with a history of ischemic cardiomyopathy (left ventricular ejection fraction 30%) and paroxysmal atrial fibrillation presents to the emergency department with palpitations. An ECG confirms rapid ventricular response atrial fibrillation. His current medications include digoxin, furosemide, lisinopril, and warfarin. Given his history of structural heart disease and the need for prompt rate control, which of the following medications requires the MOST careful monitoring for potential drug interactions if chosen for intravenous (IV) administration?

• ○ Diltiazem
• ○ Metoprolol
• ✓ Amiodarone
• ○ Verapamil

Explanation. Amiodarone has numerous drug interactions, the most important being potentiation of the effect of digoxin, beta-blockers, calcium channel blockers (CCBs), and vitamin K antagonists (VKAs) such as warfarin.

Question 25

A 58-year-old male presents with frequent premature ventricular contractions (PVCs) causing palpitations and fatigue. An echocardiogram reveals a structurally normal heart with a left ventricular ejection fraction (LVEF) of 58%. He has tried metoprolol for 3 months without significant improvement in his symptoms or PVC burden, which is estimated at 20% of his total heartbeats. Given his persistent symptoms and lack of response to medical therapy, what is the most appropriate next step in management?

• ○ Initiate amiodarone therapy.
• ✓ Refer for radiofrequency ablation.
• ○ Increase the dose of metoprolol.
• ○ Implant an implantable cardioverter-defibrillator (ICD).

Explanation. Radiofrequency ablation is recommended for symptomatic patients with ventricular arrhythmias, such as PVCs, after failure of antiarrhythmic drug (AAD) therapy. This patient is symptomatic despite beta-blocker therapy and has a significant PVC burden. Therefore, radiofrequency ablation is the most appropriate next step.

Question 26

A 68-year-old male with a history of ischemic cardiomyopathy and a prior myocardial infarction presents with recurrent episodes of sustained monomorphic ventricular tachycardia (VT). He is hemodynamically unstable during these episodes. An electrophysiology (EP) study is planned. Which of the following ablation strategies is MOST appropriate during the procedure?

• ○ Activation mapping during induced VT.
• ○ Pace mapping to find the best match to the clinical VT.
• ✓ Substrate ablation targeting late potentials and local abnormal ventricular activities (LAVAs).
• ○ Focal ablation of the earliest site of activation during sinus rhythm.

Explanation. In patients with structural heart disease and poorly tolerated ventricular arrhythmias (VAs), substrate ablation, directed at ablation of late potentials and local abnormal ventricular activities (LAVAs), is often preferred over activation mapping during induced arrhythmia.

Question 27

A 35-year-old male with known long QT syndrome (LQTS) presents to the emergency department with three episodes of syncope in the past 24 hours. Each syncopal episode was preceded by palpitations. An ECG during one episode showed torsades de pointes (TdP). He denies chest pain or shortness of breath. His baseline QTc is 510 ms. Which of the following factors is most likely contributing to the patient's current presentation?

• ○ Chronic stable angina
• ○ Wolff-Parkinson-White (WPW) syndrome
• ✓ Enhanced sympathetic tone
• ○ Arrhythmogenic right ventricular cardiomyopathy (ARVC)

Explanation. Electrical storm (ES), characterized by recurrent ventricular arrhythmias (VAs) such as TdP, can occur in patients with inherited arrhythmia syndromes like LQTS. The mechanisms of ES are complex, involving triggering factors, a vulnerable electrophysiological substrate, and enhanced sympathetic tone.

Question 28

A 68-year-old male with a history of ischemic cardiomyopathy and a secondary prevention implantable cardioverter-defibrillator (ICD) presents to the emergency department. He reports receiving three ICD shocks within the past 24 hours. Review of his ICD interrogation reveals three episodes of ventricular tachycardia (VT) terminated by shock therapy, each separated by at least 5 minutes. Which of the following is the most accurate characterization of his current presentation?

• ○ Asymptomatic premature ventricular contractions (PVCs)
• ✓ Electrical storm (ES)
• ○ Ventricular fibrillation (VF)
• ○ Inappropriate ICD shocks due to lead fracture

Explanation. Electrical storm (ES) is defined as the occurrence of three or more appropriate device therapies (ICD shocks or anti-tachycardia pacing) within a 24-hour period, separated from one another by at least 5 minutes.

Question 29

A 68-year-old male with a history of ischemic cardiomyopathy and an implanted ICD (Implantable Cardioverter-Defibrillator) presents to the emergency department after receiving multiple ICD shocks at home. He is currently alert but hypotensive (BP 80/60 mmHg) and complaining of chest pain. ECG shows a rapid ventricular arrhythmia. Which of the following is the MOST appropriate next step in management?

• ○ Urgent ICD interrogation to evaluate for the appropriateness of ICD interventions.
• ○ Immediate referral to a tertiary high-volume center for ablation therapy.
• ✓ Prompt initiation of general anesthesia and mechanical ventilation.
• ○ Placement of a magnet on the ICD to temporarily suspend ICD therapies.

Explanation. Given the patient's hemodynamic instability, the most appropriate next step is prompt initiation of general anesthesia and mechanical ventilation.

Question 30

A 68-year-old male with a history of ischemic cardiomyopathy and an implanted cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple ICD shocks at home. He reports feeling lightheaded and anxious after each shock but denies syncope. His ECG shows non-sustained ventricular tachycardia (VT) at a rate of 140 bpm. He is currently on metoprolol and lisinopril. Which of the following is the MOST appropriate initial management strategy?

• ○ Initiate amiodarone and schedule catheter ablation.
• ✓ Reprogram the ICD to increase the VT detection rate and duration.
• ○ Disable VT therapies and initiate sotalol.
• ○ Increase the dose of metoprolol and observe.

Explanation. Reprogramming the ICD by increasing the detection duration and heart rate detection threshold of the VT zone can decrease mortality and reduce ICD shocks without increasing the incidence of syncope. This is an appropriate first step in managing frequent ICD shocks.

Question 31

A 58-year-old male with a history of chronic heart failure and an implantable cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple ICD shocks in the past 24 hours due to electrical storm (ES). He is currently on metoprolol for his heart failure management. An ECG confirms the presence of frequent ventricular arrhythmias (VAs). Considering the guideline recommendations for managing ES, which of the following strategies would be MOST appropriate in addition to continuing beta-blocker therapy?

• ○ Initiate intravenous procainamide.
• ○ Switch to a non-selective beta-blocker such as propranolol.
• ✓ Administer a loading dose of amiodarone in addition to the current metoprolol.
• ○ Increase the dose of metoprolol.

Explanation. The combination of amiodarone with a beta-blocker significantly reduces the risk of recurrent ICD shocks compared to a beta-blocker alone. In patients with ES, amiodarone reduces the risk of ES recurrence. Patients already on amiodarone therapy may benefit from an additional loading dose.

Question 32

A 62-year-old male presents to the emergency department with a wide-complex tachycardia at a rate of 180 bpm. He is alert and oriented, and his blood pressure is 110/70 mmHg. He has a history of a prior myocardial infarction with an ejection fraction of 45%. An ECG confirms monomorphic ventricular tachycardia (VT). Which of the following is the most appropriate initial antiarrhythmic medication?

• ○ Lidocaine
• ○ Amiodarone
• ✓ Procainamide
• ○ Sotalol

Explanation. Procainamide has been shown to be more effective and safe compared to amiodarone in the treatment of tolerated monomorphic VT.

Question 33

A 68-year-old male with a history of ischemic cardiomyopathy and an implantable cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple ICD shocks over the past hour due to incessant ventricular tachycardia (VT). He is anxious and diaphoretic, but his blood pressure is stable at 110/70 mmHg. Which of the following is the MOST appropriate initial pharmacological approach to manage his VT and reduce the frequency of ICD shocks?

• ○ Amiodarone bolus followed by infusion.
• ○ Lidocaine bolus followed by infusion.
• ✓ Midazolam combined with remifentanil.
• ○ Propofol infusion.

Explanation. For patients presenting with electrical storm (ES), sedation is recommended to reduce sympathetic tone and psychological distress caused by repetitive ventricular arrhythmias (VAs) and ICD therapies. The combination of a benzodiazepine like midazolam and a short-acting analgesic like remifentanil is preferred as the first choice due to the lack of negative inotropic effect.

Question 34

A 62-year-old male with ischemic cardiomyopathy and severe biventricular dysfunction is undergoing VT (ventricular tachycardia) ablation for recurrent, symptomatic VT refractory to antiarrhythmic medications. The electrophysiology team is concerned about potential hemodynamic decompensation during the procedure due to the patient's poor cardiac function. Based on the provided text, what prophylactic measure should be considered to improve the safety and efficacy of the ablation?

• ○ Administration of high-dose inotropic support.
• ○ Prophylactic use of biventricular pacing.
• ✓ Prophylactic use of extracorporeal membrane oxygenation (ECMO).
• ○ Placement of a left ventricular assist device (LVAD).

Explanation. In patients with significant biventricular dysfunction, a LVAD may be inadequate, and devices providing biventricular support like ECMO might be preferable. The study by Baratto et al. showed that prophylactic use of ECMO allowed safe completion of the VT ablation procedure in 92% of patients.

Question 35

A 62-year-old male with ischemic cardiomyopathy and recurrent ventricular tachycardia (VT) despite treatment with amiodarone and a previously failed catheter ablation is being considered for further management options. Which of the following surgical procedures involves removal of the lower third of the stellate ganglion and T2-T4 thoracic ganglia?

• ○ Thoracic epidural anesthesia
• ○ Stellate ganglion blockade
• ✓ Surgical cardiac sympathetic denervation (CSD)
• ○ Renal sympathetic denervation

Explanation. Surgical cardiac sympathetic denervation (CSD) involves removing the lower third of the stellate ganglion and T2-T4 thoracic ganglia, typically performed on the left side during a video-assisted thoracoscopic procedure.

Question 36

A 62-year-old male with ischemic cardiomyopathy and an implanted ICD (implantable cardioverter-defibrillator) presents with frequent episodes of electrical storm (ES) despite being on optimal medical therapy. He has been experiencing multiple ICD shocks per day, significantly impacting his quality of life. He is referred to your electrophysiology clinic for further management. What is the most appropriate recommendation based on the evidence?

• ○ Initiate anti-arrhythmic drug therapy with amiodarone.
• ○ Optimize medical therapy and continue monitoring.
• ✓ Proceed with catheter ablation of ventricular tachycardia (VT).
• ○ Refer for cardiac transplantation.

Explanation. Catheter ablation has demonstrated significant benefits in patients with drug-refractory electrical storm, including a high rate of acute elimination of inducible arrhythmias and freedom from electrical storm. The PARTITA trial demonstrated a benefit of catheter ablation of VT on the composite end point of death or worsening heart failure in patients with ischaemic or non-ischaemic cardiomyopathy who had an implanted ICD compared with a control population. Reduction of VT favourably affected survival.

Question 37

A 62-year-old male with a history of ischemic cardiomyopathy and an implanted cardioverter-defibrillator (ICD) presents to the emergency department after receiving a single appropriate shock for ventricular tachycardia (VT). He is hemodynamically stable. What is the most appropriate next step in management?

• ○ Initiate or optimize antiarrhythmic drug therapy and schedule routine follow-up.
• ✓ Refer for urgent catheter ablation of VT.
• ○ Continue current medical therapy and monitor for further ICD events.
• ○ Refer for cardiac transplantation evaluation.

Explanation. Catheter ablation may be considered after the first ICD shock in patients with ischemic and non-ischemic cardiomyopathy. A study showed that catheter ablation decreased heart failure hospitalizations and recurrent VT episodes treated with shock compared to medical therapy alone.

Question 38

A 68-year-old male with a history of ischemic cardiomyopathy, COPD (chronic obstructive pulmonary disease), and NYHA class III heart failure is being evaluated for catheter ablation of ventricular tachycardia (VT). His LVEF (left ventricular ejection fraction) is 35%, and he has a history of diabetes mellitus. Based on the provided text, which of the following strategies is MOST likely to improve his post-procedural mortality?

• ○ Avoiding mechanical support altogether due to the risks associated with its use.
• ○ Employing a rescue strategy with percutaneous left ventricular assist device (LVAD) if hemodynamic decompensation occurs during the VT ablation.
• ✓ Prophylactic placement of a percutaneous LVAD prior to VT ablation.
• ○ Aggressive fluid resuscitation during the VT ablation procedure to maintain hemodynamic stability.

Explanation. Prophylactic LVAD placement prior to VT ablation has been shown to significantly reduce 30-day mortality in high-risk patients compared to rescue LVAD or no LVAD. The patient described has multiple risk factors that are included in PAINESD score, which identifies patients that would benefit from prophylactic mechanical support.

Question 39

A 68-year-old male with a history of ischemic cardiomyopathy, a left ventricular ejection fraction (LVEF) of 35%, hypertension, and a cardiac resynchronization therapy defibrillator (CRT-D) implanted two years ago, presents with recurrent episodes of ventricular tachycardia (VT) despite being on amiodarone and a beta-blocker. He underwent a VT ablation 18 months prior, which initially reduced the frequency of episodes, but VT has recurred in the past 3 months. He denies any recent ICD shocks. According to the I-VT score, which factors are the best predictors of VT recurrence after ablation in this patient?

• ○ Age, hypertension, and ischemic cardiomyopathy
• ✓ LVEF, CRT-D, and previous VT ablation
• ○ Amiodarone use, hypertension, and LVEF
• ○ History of ICD shocks, LVEF, and age

Explanation. The I-VT score identifies LVEF, presence of an ICD/cardiac resynchronization device (CRT-D), and previous ablation as the best predictors of VT recurrence after ablation.

Question 40

A 62-year-old male with ischemic cardiomyopathy (ICM) and a history of ventricular tachycardia (VT) s/p ICD implantation presents for evaluation of recurrent VT. His current left ventricular ejection fraction (LVEF) is 25%. According to the survival tree analysis, which factor is most associated with an increased risk of VT recurrence in this patient?

• ○ Previous ablation
• ✓ LVEF less than 30%
• ○ Non-ischemic cardiomyopathy
• ○ Presence of a cardiac resynchronization therapy (CRT) device

Explanation. The survival tree analysis identified LVEF as the first decision point for VT recurrence risk. Patients with LVEF <30% had a higher VT recurrence risk.

Question 41

A 32-year-old male is brought to the emergency department after being found unresponsive at home. His ECG shows ST-segment elevation in leads V1-V3. After successful percutaneous coronary intervention (PCI), he develops polymorphic ventricular tachycardia (VT) that degenerates into ventricular fibrillation (VF). Initial attempts at cardioversion are unsuccessful. Which of the following is the MOST appropriate next step in managing this patient's arrhythmia?

• ○ Administer intravenous lidocaine
• ✓ Administer intravenous amiodarone
• ○ Administer intravenous isoprenaline
• ○ Initiate temporary atrial pacing

Explanation. In patients with ST-segment elevation myocardial infarction (STEMI) who develop persistent ventricular arrhythmias (VAs) after revascularization, amiodarone is recommended after initial therapies like cardioversion have failed. Lidocaine is reserved for arrhythmias refractory to amiodarone.

Question 42

A 62-year-old male presents to the emergency department with acute chest pain and is diagnosed with ST-elevation myocardial infarction (STEMI). He undergoes primary percutaneous coronary intervention (PCI). In the first 48 hours post-PCI, he develops sustained ventricular tachycardia (VT) requiring cardioversion. Based on the available evidence, how does this early VT/ventricular fibrillation (VF) most likely impact his prognosis?

• ○ It has no significant impact on subsequent survival.
• ○ It is associated with a decreased risk of death compared to patients without VT/VF.
• ✓ It is associated with an increased risk of death, irrespective of the patient's underlying risk profile.
• ○ It suggests that lidocaine should have been used instead of amiodarone during the initial resuscitation.

Explanation. The Assessment of Pexelizumab in Acute Myocardial Infarction (APEX AMI) trial demonstrated that ventricular tachycardia (VT)/ventricular fibrillation (VF) occurring within the first 48 hours of ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) is associated with an increased risk of death, regardless of the patient's underlying risk.

Question 43

A 62-year-old male with a history of hypertension and diabetes presents to the emergency department with acute onset chest pain. An ECG reveals ST-segment elevation in the anterior leads, and he is immediately taken for percutaneous coronary intervention (PCI). During the procedure, the patient develops ventricular fibrillation (VF), which is successfully defibrillated, and PCI is completed with TIMI grade 3 flow achieved. Post-procedure, he is started on guideline-directed medical therapy. Which of the following statements is most accurate regarding this patient's risk?

• ○ The occurrence of VF during PCI is associated with increased 3-year mortality.
• ✓ The occurrence of VF during PCI is not associated with increased 3-year mortality or major adverse events.
• ○ The occurrence of VF during PCI is associated with a decreased risk of stent thrombosis.
• ○ The occurrence of VF during PCI is an indication for immediate implantable cardioverter-defibrillator (ICD) implantation.

Explanation. The HORIZONS-AMI trial showed that most events occurred within the first 48 hours and that sustained ventricular tachycardia/ventricular fibrillation (VT/VF) was not significantly associated with increased 3-year mortality or major adverse events.

Question 44

A 62-year-old male presents to the emergency department with acute onset chest pain. An ECG reveals ST-segment elevation in the anterior leads, concerning for an acute anterior myocardial infarction (MI). He undergoes primary percutaneous coronary intervention (PCI). Post-PCI, the ECG shows accelerated idioventricular rhythm (AIVR). Which of the following statements is MOST accurate regarding the significance of AIVR in this setting?

• ○ AIVR is a specific marker of successful coronary reperfusion after PCI.
• ○ The presence of AIVR post-PCI indicates the need for immediate anti-arrhythmic therapy.
• ✓ AIVR cannot be used as a reliable marker of successful reperfusion in the PCI era.
• ○ AIVR, in combination with ST-segment resolution of less than 50%, has a high positive predictive value for successful reperfusion.

Explanation. In the current PCI era, AIVR does not reliably indicate successful reperfusion. There is no difference in AIVR occurrence in patients with TIMI 3 flow (normal flow) and TIMI 2 flow (reduced flow).

Question 45

A 62-year-old male presents to the emergency department with acute chest pain. He is diagnosed with an ST-elevation myocardial infarction (STEMI) and receives thrombolytic therapy. Following thrombolysis, he is transferred to a PCI-capable center for percutaneous coronary intervention (PCI). During the initial hours post-PCI, the patient develops accelerated idioventricular rhythm (AIVR). He is hemodynamically stable and asymptomatic. What is the MOST appropriate next step in managing this patient?

• ○ Administer intravenous amiodarone.
• ○ Initiate treatment with a beta-blocker.
• ✓ No specific treatment is needed for the AIVR.
• ○ Perform emergent repeat angiography to assess for stent thrombosis.

Explanation. In patients treated with both thrombolysis and PCI, AIVR presents no clinical threat and does not need any specific treatment.

Question 46

A 68-year-old male with a history of coronary artery disease presents to the emergency department with palpitations and lightheadedness. An ECG reveals a wide QRS complex tachycardia at a rate of 180 bpm. Which of the following is the MOST important initial step in the differential diagnosis?

• ○ Obtain a detailed history focusing on previous episodes and triggers.
• ○ Immediately administer intravenous adenosine.
• ✓ Determine if the rhythm is ventricular tachycardia or supraventricular tachycardia with aberrant conduction.
• ○ Perform a carotid sinus massage.

Explanation. The initial and most critical step in evaluating a wide QRS complex tachycardia is to differentiate between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with aberrant conduction. This distinction guides subsequent management decisions, as treatments differ significantly between the two conditions.

Question 47

A 62-year-old male with a history of myocardial infarction and an implanted cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple appropriate ICD shocks over a 24-hour period. He reports feeling unwell and anxious but denies chest pain. His ECG shows frequent episodes of polymorphic ventricular tachycardia (VT) degenerating into ventricular fibrillation (VF). This presentation is most accurately described as:

• ○ Monomorphic VT
• ✓ Electrical storm
• ○ Accelerated idioventricular rhythm
• ○ Torsades de pointes

Explanation. Electrical storm is defined as frequent episodes of VT or VF requiring intervention (e.g., ICD shocks, anti-tachycardia pacing) within a short period (typically 24 hours).

Question 48

A 62-year-old male with ischemic cardiomyopathy and an implantable cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple appropriate ICD shocks over the past 24 hours. He reports feeling increasingly weak and anxious. His ECG shows frequent episodes of monomorphic ventricular tachycardia (VT) interspersed with sinus rhythm. This presentation is best described as:

• ○ Accelerated idioventricular rhythm
• ○ Ventricular fibrillation
• ✓ Electrical storm
• ○ Torsades de pointes

Explanation. Electrical storm is characterized by frequent episodes of ventricular tachycardia or ventricular fibrillation requiring multiple ICD interventions within a short period.

Question 49

A 68-year-old male with a history of ischemic cardiomyopathy and an implanted cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple appropriate ICD shocks for ventricular tachycardia (VT) over the past 24 hours. He is currently hemodynamically stable, and his ECG shows a stable VT at a rate of 180 bpm. His ICD is programmed to deliver antitachycardia pacing (ATP) and then shock if ATP is unsuccessful. Given the frequent VT episodes and ICD interventions, what is the MOST appropriate acute management strategy?

• ○ Increase the dose of his current antiarrhythmic medication.
• ○ Program the ICD to deliver more aggressive ATP therapy for VT.
• ✓ Initiate intravenous amiodarone and consider catheter ablation.
• ○ Schedule elective ICD explant and placement of a subcutaneous array.

Explanation. Frequent ICD shocks, even with ATP programmed, indicate a need for more aggressive management. While ATP is a valuable initial strategy, recurrent VT despite ATP warrants consideration of antiarrhythmic drugs like amiodarone and evaluation for catheter ablation to reduce the VT burden.

Question 50

A 62-year-old male with a history of ischemic cardiomyopathy, status post-myocardial infarction (MI) and an ejection fraction of 30%, presents to the emergency department after experiencing three episodes of sustained monomorphic ventricular tachycardia (SMVT) in the past 24 hours. He has an implantable cardioverter-defibrillator (ICD) that has delivered appropriate shocks for each episode. He is currently hemodynamically stable. Which of the following is the MOST appropriate initial pharmacological treatment?

• ○ Amiodarone
• ○ Lidocaine
• ✓ Procainamide
• ○ Sotalol

Explanation. Procainamide is effective in terminating sustained monomorphic ventricular tachycardia.

Question 51

A 68-year-old male with a history of coronary artery disease and prior myocardial infarction presents to the emergency department with sustained monomorphic ventricular tachycardia (VT). He is hemodynamically stable. Which of the following intravenous medications has been evaluated for termination of sustained monomorphic VT in patients with coronary artery disease with or without healed myocardial infarction?

• ○ Procainamide
• ○ Amiodarone
• ✓ Lidocaine
• ○ Propofol

Explanation. Intravenous lidocaine has been evaluated for the termination of sustained monomorphic ventricular tachycardia in patients with coronary artery disease with or without healed myocardial infarction.

Question 52

A 22-year-old male with known catecholaminergic polymorphic ventricular tachycardia (CPVT) presents to the emergency department after experiencing an episode of syncope during exercise. He is currently asymptomatic. His ECG shows normal sinus rhythm with a prolonged QT interval. He is already on a beta-blocker at maximum tolerated dose, but continues to have breakthrough episodes. Which of the following interventions should be considered next, given his persistent symptoms despite optimal medical therapy?

• ○ Initiation of amiodarone therapy
• ○ Implantation of an implantable cardioverter-defibrillator (ICD)
• ✓ Left cardiac sympathetic denervation
• ○ Stellate ganglion blockade

Explanation. Left cardiac sympathetic denervation has been shown to be effective in managing catecholaminergic polymorphic ventricular tachycardia (CPVT), particularly in patients who continue to have symptoms despite beta-blocker therapy.

Question 53

A 62-year-old male with a history of ischemic cardiomyopathy and an implanted cardioverter-defibrillator (ICD) presents to the emergency department after receiving multiple ICD shocks over the past 24 hours. He is currently hemodynamically stable but continues to experience frequent episodes of ventricular tachycardia (VT) despite maximal tolerated doses of amiodarone and lidocaine. Endocardial and epicardial catheter ablation attempts have been unsuccessful. What is the MOST appropriate next step in managing this patient's refractory VT storm?

• ○ Initiate high-dose sotalol infusion.
• ✓ Perform surgical left cardiac sympathetic denervation (LCSD).
• ○ Increase the amiodarone dose beyond recommended limits.
• ○ Refer for urgent heart transplantation evaluation.

Explanation. When endocardial and epicardial catheter ablation attempts for ventricular arrhythmias fail, alternative interventional procedures such as surgical left cardiac sympathetic denervation (LCSD) can be considered, especially in the setting of refractory VT storm.

Question 54

A 62-year-old male with a history of Brugada syndrome presents to the emergency department after being resuscitated from sudden cardiac arrest. An ECG confirms the diagnosis. Which of the following has been associated with electrical storm in patients with Brugada syndrome?

• ○ Late repolarization
• ○ Prolonged QT interval
• ✓ Early repolarization
• ○ ST-segment depression

Explanation. Electrical storm in patients with Brugada syndrome is associated with early repolarization.

Question 55

A 62-year-old male presents to the emergency department with acute onset chest pain and ST-segment elevation in the inferior leads on his ECG (electrocardiogram). He is immediately taken for primary percutaneous coronary intervention (PCI). During the procedure, he develops ventricular fibrillation (VF) that is successfully defibrillated. Post-PCI, he remains hemodynamically stable. Which of the following is the MOST important prognostic consideration regarding the episode of VF?

• ○ The occurrence of VF during primary PCI has no significant impact on long-term mortality if successfully treated.
• ✓ The occurrence of VF during primary PCI is associated with increased risk of mortality and stent thrombosis.
• ○ The occurrence of VF during primary PCI is only significant if it persists beyond 24 hours post-procedure.
• ○ The occurrence of VF during primary PCI is primarily related to the type of stent used and not an independent risk factor.

Explanation. Early ventricular tachycardia or fibrillation in patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI is associated with increased risk of mortality and stent thrombosis.

Question 56

A 62-year-old male presents to the emergency department with acute onset chest pain and ST-segment elevation in the anterior leads on his ECG (electrocardiogram). He is immediately taken for percutaneous coronary intervention (PCI). Post-PCI, which electrocardiographic finding is most indicative of successful reperfusion?

• ○ Resolution of ST-segment elevation
• ○ Development of new Q waves
• ○ T-wave inversion
• ✓ Appearance of accelerated idioventricular rhythm

Explanation. The appearance of accelerated idioventricular rhythm is a marker of successful reperfusion after thrombolysis or PCI.