Trifascicular and complete heart block with anterior myocardial infarction. Electrocardiographic patterns and long-term medical management.

A 45-year-old man exhibited various patterns of delay in trifascicular conduction, culminating in complete heart block during acute myocardial infarction. A temporary pacemaker was utilized for the short period of heart block. Delay in ventricular conduction subsided, and the patient refused implantation of a permanent pacemaker. Ventricular irritability, which was detected eight months later, was suppressed with administration of digitalis, guided by testing with acetylstrophanthidin. Neither heart block nor delay in ventricular conduction recurred during 43 months after the infarction. In certain patients with heart block complicating anterior myocardial infarction, long-term prognosis may be dictated by coronary and myocardial residual function, rather than by the hazard of recurrent heart block.