DC Clinical Procedures & Protocols 2 — Questions and Answers
Question 1: When performing synchronized cardioversion for unstable atrial fibrillation, the synchronization marker should align with which ECG component?
- P wave
- QRS complex (Correct answer)
- T wave
- U wave
Correct answer: QRS complex
The defibrillator's sync mode delivers the shock on the R wave of the QRS complex to avoid the vulnerable T-wave period.
Question 2: A patient in pulseless ventricular tachycardia should receive which immediate intervention?
- Synchronized cardioversion at 100 J
- Unsynchronized defibrillation (Correct answer)
- IV adenosine 6 mg
- Vagal maneuvers
Correct answer: Unsynchronized defibrillation
Pulseless VT is treated identically to VF with immediate unsynchronized defibrillation because there is no perfusing rhythm to synchronize to.
Question 3: During a code, the team leader calls for a rhythm check. The monitor shows a flat line. What is the most appropriate next action?
- Immediately defibrillate
- Check lead connections and gain settings (Correct answer)
- Administer atropine 1 mg IV
- Begin transcutaneous pacing
Correct answer: Check lead connections and gain settings
A flatline may represent artifact or a loose lead rather than true asystole, so verifying lead placement and monitor settings is the first step.
Question 4: What is the maximum recommended single dose of IV amiodarone for acute conversion of stable monomorphic VT?
- 75 mg over 10 min
- 150 mg over 10 min (Correct answer)
- 300 mg over 10 min
- 450 mg over 10 min
Correct answer: 150 mg over 10 min
The standard ACLS dose for stable monomorphic VT is amiodarone 150 mg IV infused over 10 minutes.
Question 5: A patient receiving IV procainamide develops hypotension. The most appropriate immediate action is to:
- Increase the infusion rate
- Stop or slow the infusion and give a fluid bolus (Correct answer)
- Switch to lidocaine immediately
- Administer calcium gluconate
Correct answer: Stop or slow the infusion and give a fluid bolus
Procainamide's vasodilatory properties can cause hypotension; slowing or stopping the infusion and supporting blood pressure with fluids is the priority.
Question 6: Which ECG finding is a contraindication to the use of adenosine for SVT?
- Regular narrow-complex rhythm
- Presence of delta waves with wide QRS (Correct answer)
- Resting heart rate of 170 bpm
- Absence of visible P waves
Correct answer: Presence of delta waves with wide QRS
Adenosine can precipitate rapid conduction down an accessory pathway in pre-excitation syndromes (WPW), potentially causing ventricular fibrillation.
Question 7: When transcutaneous pacing is initiated for symptomatic bradycardia, capture is confirmed by:
- Pacing spikes visible on the monitor
- Spike followed by a wide QRS and a palpable pulse (Correct answer)
- Patient reporting chest discomfort
- Heart rate increasing to 60 bpm on the monitor alone
Correct answer: Spike followed by a wide QRS and a palpable pulse
True mechanical capture requires both an ECG-confirmed paced complex (spike + wide QRS) and a palpable pulse confirming myocardial contraction.
DC Clinical Procedures & Protocols 2
When performing synchronized cardioversion for unstable atrial fibrillation, the synchronization marker should align with which ECG component?