Wide Complex Tachycardias: What is the Lewis lead and how you can use modified ECG leads to help make the diagnosis

ECG Weekly Workout with Dr. Amal Mattu


A 60-year-old male presents to the ED with acute chest pain and lower extremity edema. He is noted to be tachycardic on arrival. The following ECG is obtained:

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

  1. What ECG abnormalities do you see?
  2. Is the rhythm most likely ventricular or atrial in origin?
  3. Are there any supplemental ECG leads that can help further distinguish the rhythm?