A Post-Arrest ECG With a Dangerous New Bundle Branch Block

ECG Weekly Workout with Dr. Amal Mattu

HPI

A 72-year-old man is brought to the ED after a witnessed out-of-hospital cardiac arrest. Bystander CPR is started quickly, EMS finds a non-shockable rhythm, and ROSC is achieved after one dose of epinephrine. He arrives intubated and unresponsive. His chart reveals a history of coronary artery disease, hypertension, and hyperlipidemia. The post-ROSC ECG computer interpretation calls bifascicular block and an old septal infarct. A prior ECG does not show the same conduction pattern.

Before accepting the computer interpretation, ask yourself:

    1. What ST segment changes are expected in V1 and V2 with an uncomplicated right bundle branch block?
    2. How much ST elevation in V1 or V2 is acceptable when RBBB is present?
    3. If the ECG is suspicious but not diagnostic, what should you do next?