The prevalence of ventricular septal defect in elementary school children in the City of Toronto.

A knowledge of the prevalence of ventricular septal defect in different age groups is basic to the estimation of all complications of this disease. The Cardiac Registry in the City of Toronto has provided this information for elementary school children. Clinical diagnosis of ventricular septal defect was made if the child had a pansystolic murmur in the 3rd or 4th left intercostal space with a palpable thrill and/or electrocardiographic evidence of ventricular hypertrophy and/or radiologic evidence of pulmonary plethora at one or more examinations. When possible, the diagnosis was confirmed by cardiac catheterization. Children with the same murmur, no thrill and normal electrocardiogram and radiograph were labelled "probable" and presumed to have a minute or disappearing defect.The prevalence rate of ventricular septal defect in elementary school children varied betwen 0.44 and 0.48 per 1000 in four successive years of study. The rate of "probable" ventricular septal defect varied between 0.27 and 0.37 per 1000 children.