QRS interval fails to predict coronary disease incidence. The Framingham Study

The Framingham Study cohort of 5209 white men and women was examined to determine the long-term incidence of manifestations of new coronary heart disease as a function of QRS interval on subjects' baseline electrocardiograms (recorded at the 9th biennial examination). Over 18 years of follow-up, age-adjusted incidence of myocardial infarction, angina pectoris, and coronary death appeared unrelated to baseline QRS prolongation in both sexes, by Cox regression. Subjects with left bundle-branch block fared no worse than those with right pattern. These relations held whether or not subjects with baseline electrocardiographic abnormalities other than intraventricular block were excluded from consideration. In sum, QRS duration is an unimportant predictor of coronary disease in this Framingham population.