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RIGHT BUNDLE BRANCH BLOCK AND PROGNOSIS AFTER ACUTE MI.

Right bundle branch block (RBBB) is a common finding after acute myocardial infarction, but its prognostic importance is unclear. These investigators analyzed its prognostic significance in 1325 patients who were treated for anterior acute MIs at six hospitals in California, Canada, and Switzerland. RBBB occurred in 178 patients, 393 developed conduction defects other than RBBB, and 754 had no conduction defects. Compared to patients without conduction defects, those with RBBB had a higher mortality rate during hospitalization (32 vs. 8 percent) and during the year after discharge (17 vs. 7 percent); multivariate analysis confirmed RBBB to be an independent predictor. However, these high death rates occurred largely in those patients with RBBB who had evidence of left ventricular failure during hospitalization; these patients had a predischarge mortality rate of 43 percent and a one-year postdischarge mortality rate of 24 percent, compared with rates of 4 and 5 percent, respectively, in patients with RBBB and no evidence of left ventricular failure.

These data suggest that RBBB after anterior acute MI is an indicator of poor prognosis, but that the increased mortality occurs only in patients with evidence of heart failure.

— THL

Published in Journal Watch General Medicine March 26, 1991

Citation(s):

Ricou F et al. Influence of right bundle branch block on short- and long-term survival after acute anterior myocardial infarction. J Am Coll Cardiol 1991 Mar 15 17 858-863.

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