The fate of patients with intraventricular conduction disturbances complicating acute myocardial infarction.

The partial incidence and the early and late mortality were studied in 104 patients with acute myocardial infarction complicated by intraventricular conduction defects. Right bundle branch block and left anterior hemiblock had a greater incidence than the other conduction anomalies, while the hospital mortality was greater for the complete right bundle branch block combined with left anterior or posterior hemiblock, followed in order by complete left bundle branch block. Late morality was higher in cases with complete right bundle branch block combined with left posterior hemiblock and also in cases with focal block or left bundle branch block indicating a poor prognosis for these patients. For the rest sub-groups of patients late mortality was relatively low indicating the possibility of long survival after passing the acute phase. However, longer periods of observation are desirable for further estimation of their ultimate prognosis.