24. Rabkin, S.W., Mathewson, F.A.L., Tate, R.B.: Relationship of ventricular ectopy in men without apparent heart disease to occurrence of ischemic heart disease and sudden death. Am Heart J 101 (2): 135-142, 1981. The purpose of this investigation was to determine whether ventricular ectopic beats, or ventricular premature beats (VPBs), on routine electrocardiograms in men without apparent heart disease predict the later occurrence of clinical manifestations of ischemic heart disease (IHD). The Manitoba Study cohort consisted of 3983 men predominantly between 25 and 34 years of age and free of IHD at entry. During the 29-year observation period, 401 persons without clinical evidence of heart disease had VPBs on an electrocardiogram at a routine examination. They were followed (10.8 + 0.5 SEM) years and 13.5% (54 men) later manifested IHD. Age-specific total IHD incidence was significantly (p<0.05) greater for men 40 to 59 years of age at VPB occurrence compared to men of the same age without VPBs. The clinical manifestation with the strongest association with VPBs was sudden death. VPB characteristics of frequency, configuration, coupling interval, and postextrasystolic T-wave change did not distinguish those who developed IHD. Prematurity index (R-R'/QT) showed a trend toward an association of late coupled ectopic beats (R-R'/QT >1.6) and IHD risk. However, faster basic ventricular rate plus VPBs significantly correlated with greater IHD probability. Thus ventricular ectopic beats on a routine electrocardiogram in men over 40 years of age without apparent heart disease identify those a high risk for a clinical IHD event, especially sudden death.