Prognostic factors in right bundle-branch block complicating acute myocardial infarction.

Abstract

Summary: Seventy patients with right bundle-branch block (RBBB), comprising 6% of 1083 patients with acute myocardial infarction, were admitted to our coronary care unit (CCU) over a five-year period. Thirty-eight of them died in hospital. Their prognosis was not altered significantly by the presence of complete heart block (CHB), bilateral bundle-branch block or the site of infarction and serum enzyme levels. Hospital mortality was lower (p<0.015) among eight patients with transient RBBB of whom one died. The high mortality appeared to be due mainly to extensive infarction. All 32 survivors were followed from two to 50 months and 15 have died. Four patients who had had bilateral bundle-branch block or CHB died suddenly. Although no sudden deaths occurred in those with RBBB alone the mortality at six, 12 and 18 months did not differ significantly from patients with bilateral bundle-branch block. Of the 17 patients still alive eleven have persistent RBBB, one has bilateral bundle-branch block, one has required permanent pacing for Stokes-Adams attacks and four have a QRS complex of normal duration. The late sudden deaths suggest that permanent pacing may have a place in the management of patients with bilateral bundle-branch block surviving infarction.