Cardiac involvement by non-Hodgkin's lymphoma: an unusual presentation of heart conduction disturbances.

A 57-year-old man with non-Hodgkin's lymphoma presented with solitary sinus node dysfunction. Superior vena cava syndrome and progressive disturbance of the conduction system requiring dual chamber pacemaker implantation later appeared. Combination chemotherapy and radiation reversed abnormal sinus node function and the AV conduction disturbance, as demonstrated during electrophysiological evaluation.