Bundle branch block after myocardial infarction--a long term follow-up.

Fifty-two patients with myocardial infraction complicated by bundle branch block (27 RBBB and 25 LBBB) survived the hospital period (1967--1972), and were followed up to December 1976. Actuarial survival curves revealed a worse mortality up to five years (P less than 0.05) for LBBB (68%) than for RBBB (33%). All deaths occurred in the first four years. In RBBB, additional hemiblock (seven patients) did not increase the risk of heart block nor worsen the prognosis--one death in seven patients (14%) compared to eight in 20 patients with isolated RBBB (40%). The previous literature on long term survival of BBB was reviewed. Recommended treatment for BBB, a marker of severe myocardial damage, includes antiarrhythmic prophylaxis for anteroseptal infarction with RBBB, aneurysmectomy in selected subsets of patients, and possibly prevention of RBBB or its complications by treatment for reduction of infarct size during the very early phase after onset of infarction.