ECG Case of the Month. Out-of-Hospital Cardiac Arrest. DIAGNOSIS: Atrial fibrillation with a rapid ventricular response (150 beats/minute) and right bundle branch block.

A muscular-appearing 50-year-old man was found down in his home by family members. Paramedics documented pulseless electrical activity and began cardiopulmonary resuscitation that included placement of an endotracheal tube. The resuscitation was continued in the hospital emergency department (ED), and after 20 minutes, an arterial pulse returned.