IBHRE Practice Exam 4 With 100% Correct Answers

IBHRE Practice Exam 4 With 100% Correct Answers

1. Which of the following arrhythmias is typically treated with anti-tachycardia
pacing (ATP) by an ICD?

• A) Atrial fibrillation
• B) Ventricular tachycardia
• C) Sinus tachycardia
• Answer: B) Ventricular tachycardia
• Explanation: Anti-tachycardia pacing (ATP) is commonly used to terminate ventricular
tachycardia by delivering rapid, controlled pacing impulses.

2. What is the purpose of the pacemaker’s refractory period?

• A) Prevents oversensing of T waves
• B) Extends battery life
• C) Ensures consistent ventricular pacing
• Answer: A) Prevents oversensing of T waves
• Explanation: The refractory period prevents the device from detecting and reacting to T waves
or other signals immediately following depolarization.

3. In pacemaker programming, what is the function of the AV delay?

• A) Determines the time between atrial and ventricular pacing
• B) Sets the pacing output voltage
• C) Controls ventricular sensing
• Answer: A) Determines the time between atrial and ventricular pacing
• Explanation: The AV delay is the programmed time interval between atrial and ventricular
events, helping to mimic natural AV conduction.

4. Which wave on an ECG represents atrial depolarization?

• A) QRS complex
• B) P wave
• C) T wave
• Answer: B) P wave
• Explanation: The P wave reflects atrial depolarization, the electrical activity initiating atrial
contraction.

5. What feature in ICDs is commonly used to avoid inappropriate shocks due to
supraventricular tachycardia?

• A) Lower sensitivity
• B) Rate cut-off settings

, • C) Dual-chamber sensing
• Answer: C) Dual-chamber sensing
• Explanation: Dual-chamber sensing helps the ICD distinguish between ventricular and atrial
arrhythmias, avoiding inappropriate therapy for supraventricular tachycardias.

6. Which pacing mode is most appropriate for a patient with atrial fibrillation
and AV block?

• A) AAI
• B) DDD
• C) VVI
• Answer: C) VVI
• Explanation: In patients with atrial fibrillation and AV block, VVI mode paces the ventricle
independently, as atrial sensing isn’t necessary.

7. What does the QT interval represent on an ECG?

• A) Duration of atrial depolarization and repolarization
• B) Duration of ventricular depolarization and repolarization
• C) Duration of ventricular depolarization
• Answer: B) Duration of ventricular depolarization and repolarization
• Explanation: The QT interval reflects the total time for ventricular depolarization and
repolarization, critical for assessing rhythm disturbances.

8. Which arrhythmia is most likely to cause sudden cardiac arrest?

• A) Atrial fibrillation
• B) Ventricular fibrillation
• C) Atrial flutter
• Answer: B) Ventricular fibrillation
• Explanation: Ventricular fibrillation is a disorganized, life-threatening rhythm leading to sudden
cardiac arrest due to a lack of effective pumping.

9. What is the primary use of rate-responsive pacemakers?

• A) Increase heart rate in response to physical activity
• B) Reduce heart rate during rest
• C) Maintain constant pacing rate
• Answer: A) Increase heart rate in response to physical activity
• Explanation: Rate-responsive pacemakers adjust the pacing rate based on the patient’s activity,
addressing chronotropic incompetence.

10. What does "undersensing" refer to in a pacemaker context?

• A) Detecting too many signals
• B) Failing to detect intrinsic beats