STAT ECG Diagnoses: ventricular fibrillation after synchronized cardioversion for a regular wide complex tachycardia

ECG Weekly Workout with Dr. Amal Mattu


A 50-year-old male is brought into the ED with palpitations and is found to have a regular wide complex tachycardia. He is treated with synchronized electrical cardioversion and immediately goes into ventricular fibrillation. The initial ECG and rhythm strip during cardioversion is shown below:

Before watching the video, look closely at this ECG and ask yourself:

  1. What is the most likely rhythm diagnosis based on the 12-lead ECG?
  2. What is the most likely reason for deterioration into ventricular fibrillation after cardioversion?
  3. What would be your next step in management?