Bundle-Branch Block

As part of an inclusive health examination of the population of Tecumseh, Michigan, electrocardiograms were recorded from 8,641 persons of all ages, 87.9 per cent of those living in the study area. Eighteen persons, twelve men and six women, had complete right bundle-branch block and a like number, composed of six men and 12 women, had left. All affected persons were past 20 years of age and 67 per cent were past 60. Twenty-five of the 36 persons had no clinical evidence of valvular heart disease, angina pectoris, or myocardial infarction. Bundle-branch block occurred mostly in the older age groups where there was a high prevalence of hypertension, hypercholesteremia, hyperglycemia, and obesity, although these conditions were no more frequent among the affected persons than among others of the same age and sex.