Sinus arrest associated with continuous-infusion cimetidine.

The administration of intermittent intravenous infusions of cimetidine is infrequently associated with the development of bradyarrhythmias. A 40-year-old man with leukemia and no history of cardiac disease developed recurrent, brief episodes of apparent sinus arrest while receiving continuous-infusion cimetidine 50 mg/hour. The arrhythmias were temporally related to cimetidine administration, disappeared after dechallenge, and did not recur during ranitidine treatment. This is the first reported case of sinus arrest associated with continuous-infusion cimetidine.