Complete Bundle-Branch Block Complicating Acute Myocardial Infarction

Abstract

Bundle-branch block complicated 68 out of 806 cases of acute myocardial infarction managed in a coronary-care unit and was associated with a mortality of 56 per cent. Twenty-five out of 48 patients with right-bundle-branch block, and 13 of 20 patients with left-bundle-branch block died. In 21 of the 68 patients complete heart block subsequently developed, and in 13 of these an idioventricular pacemaker failed to emerge. Bilateral bundle-branch block preceded the onset of complete heart block in 15 patients. Transvenous pacing electrodes were inserted prophylactically in the last 31 consecutive cases of bundle-branch block. This procedure was associated with a high proportion of life-threatening arrhythmias, and pacing did not reduce subsequent mortality in the nine patients in whom complete heart block developed.