DC Dysrhythmia Emergency Response & Intervention 3 — Questions and Answers
Question 1: A patient in stable wide-complex tachycardia of uncertain origin is seen in the ED. What is the safest initial approach?
- Treat as supraventricular tachycardia and give adenosine
- Treat as ventricular tachycardia until proven otherwise (Correct answer)
- Perform immediate unsynchronized cardioversion
- Administer diltiazem IV to slow the rate
Correct answer: Treat as ventricular tachycardia until proven otherwise
Wide-complex tachycardia of uncertain origin should be treated as VT because misidentifying VT as SVT can lead to dangerous interventions.
Question 2: After successful defibrillation, a patient's rhythm converts to sinus tachycardia at 110 bpm but remains unresponsive with no palpable pulse. What should the team suspect?
- Return of spontaneous circulation
- Pulseless electrical activity (Correct answer)
- Accelerated idioventricular rhythm
- Junctional tachycardia
Correct answer: Pulseless electrical activity
An organized rhythm without a palpable pulse is pulseless electrical activity, requiring continued CPR and treatment of reversible causes.
Question 3: Which of the following represents the correct initial energy dose for synchronized cardioversion of hemodynamically unstable atrial flutter?
- 50–100J biphasic (Correct answer)
- 200J biphasic
- 360J monophasic only
- 120J then immediately increase to 360J
Correct answer: 50–100J biphasic
Atrial flutter typically responds to low energy levels of 50–100J biphasic for synchronized cardioversion.
Question 4: A patient with Wolff-Parkinson-White syndrome develops rapid atrial fibrillation. Which medication is contraindicated?
- Procainamide IV
- IV verapamil (Correct answer)
- Ibutilide IV
- Electrical cardioversion
Correct answer: IV verapamil
AV nodal blocking agents like verapamil and diltiazem are contraindicated in WPW with AF because they can accelerate conduction through the accessory pathway, causing VF.
Question 5: During transcutaneous pacing for complete heart block, you see pacing spikes on the monitor but the patient remains unresponsive with no pulse. What is the most likely problem?
- The pacing rate is set too low
- Pacing capture has not been achieved (Correct answer)
- The rhythm has converted to VF
- Current output is too high, causing artifact
Correct answer: Pacing capture has not been achieved
Electrical activity on the monitor without a palpable pulse indicates failure to achieve mechanical capture despite pacing spikes.
Question 6: A patient with symptomatic sinus bradycardia at 38 bpm does not respond to atropine. What is the next ACLS intervention?
- Administer adenosine 6 mg IV push
- Begin transcutaneous pacing (Correct answer)
- Administer amiodarone 300 mg IV bolus
- Perform unsynchronized cardioversion at 200J
Correct answer: Begin transcutaneous pacing
If atropine fails to correct symptomatic bradycardia, transcutaneous pacing is the next recommended step while arranging transvenous pacing.
Question 7: Which post-cardiac arrest intervention has been shown to improve neurological outcomes after ROSC?
- Immediate aggressive hyperventilation to reduce PaCO2 below 30 mmHg
- Targeted temperature management to 32–36°C (Correct answer)
- Immediate high-dose corticosteroid therapy
- Maintaining systolic BP below 80 mmHg to reduce cardiac workload
Correct answer: Targeted temperature management to 32–36°C
Targeted temperature management (TTM) at 32–36°C for 24 hours post-ROSC is evidence-based for neuroprotection after cardiac arrest.
DC Dysrhythmia Emergency Response & Intervention 3
A patient in stable wide-complex tachycardia of uncertain origin is seen in the ED.
What is the safest initial approach?