Electrocardiographic findings in 67,375 asymptomatic subjects: III. Ventricular rhythms ∗

Abstract

An electrocardiographic analysis of 67,375 healthy, asymptomatic men has been conducted and the incidence of various types of ventricular rhythms determined. All known forms of ventricular rhythm were detected except ventricular flutter and ventricular fibrillation. Four hundred nineteen cases of premature ventricular contractions were noted (0.6 per cent), of which twenty-two were interpolated and one multifocal. Bigeminy, trigeminy and quadrigeminy were each noted in a few subjects. There was a twofold increase in the rate of premature ventricular contractions per 1,000 subjects in the forty to forty-four year age group as compared to the younger age groups, and a threefold increase above forty-five years of age. The average heart rate of subjects with numerous premature ventricular contractions was the same as that of subjects with rare premature beats, indicating that heart rate is not a significant determinant of the frequency of ectopic ventricular beats. The ratio of premature ventricular contractions originating in the right ventricle (QRS pattern of left bundle branch block) to those from the left ventricle (QRS pattern of right bundle branch block) was 3 to 1. There was a fourfold increase in the rate per 1,000 of the former from the youngest to the oldest age group, but no increase in rate of the latter with age. There were eighteen subjects with ventricular parasystole (0.03 per cent) and one with ventricular tachycardia. Four subjects with idioventricular rhythm with A-V dissociation were presented. These demonstrate the passive assumption of control of cardiac excitation by a ventricular focus upon slowing or failure of the sinus node. This occurred in preference to either an atrial or nodal focus which in most subjects are active under such circumstances.