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. An electrocardiogram (ECG) was obtained (Figure 1). Meanwhile, a past history established that the patient was a personal trainer who seemed fit and healthy until 10 days earlier, when he came to the ED because he had begun to lose his balance and fall frequently. Computed tomography (CT) at that time revealed lytic lesions in the fifth lumbar vertebra and extensive retroperitoneal lymphadenopathy involving the aortic, iliac, and obturator chains and the perirectal region. Arrangements had then been made for outpatient workup of a presumed malignancy.