Complete Atrioventricular Block Secondary to Pulmonary Embolism

We describe a 73-year-old woman with a history of breast cancer and metastatic disease diagnosed in January 2002 (stable when we saw her) who was admitted for sudden dyspnea and presyncope. Complete atrioventricular block was documented, and a temporary pacemaker was implanted. Eight hours after admission she recovered sinus rhythm with left bundle branch block as seen in previous recordings. Computed tomography showed bilateral pulmonary thromboembolism. An electrophysiological study showed normal atrioventricular conduction. We suggest that in this patient, who had previous left bundle branch block, pulmonary thromboembolism may have induced transient right bundle branch block, which in turn caused atrioventricular block.