Phase 4 Block

Case 112: A 73-Year-Old Man in the Arrhythmia Clinic History Diagnosis History A 73-year-old man is seen in arrhythmia clinic for routine follow-up.  He is asymptomatic.  His ECG is recorded below: Diagnosis Atrial fibrillation  Intermittent left bundle branch block pattern secondary to phase IV block ECG ID: E802