Newly acquired left bundle-branch block: the Framingham study.
The clinical implications of newly acquired left bundle-branch block (LBBB) were examined prospectively in the Framingham Study population. During 18 years of observation 55 people developed LBBB. The mean age at the onset of LBBB was 62; LBBB occurred largely in people with antecedent hypertension, cardiac enlargement, coronary heart disease, or a combination of these. Coincident with or subsequent to the onset of LBBB, 48% developed clinical coronary disease or congestive failure for the first time. Throughout the entire period of observation only 11% remained free of clinically apparent cardiovascular abnormalities. Within 10 years of the onset of LBBB, 50% had died from cardiovascular diseases. In men, the appearance of LBBB contributed independently to an increased risk of cardiovascular disease mortality. Comparison with age- and sex-matched control subjects free from LBBB confirmed that in the general adult population, newly acquired LBBB is most often a hallmark of advanced hypertensive or ischemic heart disease, or both.
D000328:Adult; D000367:Age Factors; D002037:Bundle-Branch Block / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D006332:Cardiomegaly / Q000150:complications; D002318:Cardiovascular Diseases / Q000150:complications* / Q000401:mortality; D002986:Clinical Trials as Topic; D003327:Coronary Disease / Q000150:complications; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008404:Massachusetts; D008875:Middle Aged