The detection of heart disease in children. Results of a mass field trial with use of tape-recorded heart sounds.

Abstract

A mass field trial was accomplished utilizing a heart sounds tape-recording procedure to detect organic heart disease in school children. The survey involved 35,934 children, with selection of an 8.2 per cent stratified random sample of Chicago elementary public-school children, drawn from eight representative geographic-socioeconomic-racial areas of the city. Of the total base population, 33,026 (91.9 per cent) were recorded. A total of 506 children was recalled for direct auscultation, based on suspicious findings on the tape recordings. Effective detection required that the tapes be interpreted by two specially trained cardiologists. Of the 506 children scheduled for recall, 492 were actually examined; 85 were evaluated as having probable organic heart disease, and were referred for complete work-up. Definite organic heart disease was ultimately diagnosed in 64 children, of whom 48 had congenital heart disease and 16 rheumatic heart disease. The prevalence rate of organic heart disease in the stratified random sample was 2 per 1,000, 1.5 for congenital heart disease and 0.5 for rheumatic heart disease. Of the total cases, 1 per 1,000 were previously unknown; all such cases have been brought under appropriate medical management as a result of their detection. A special study of the nonrespondents (those not tape recorded) revealed a six-fold higher prevalence rate of organic heart disease in these children, compared with those surveyed. A census was also made of cardiac children in special schools for the handicapped, in hospitals, or under home care. Based on the data from the sample, the nonrespondent study, and the foregoing census, the over-all prevalence rate of organic heart disease in Chicago elementary public-school children was estimated to be 3.4 per 1,000, 2.1 for congenital heart disease and 1.3 for rheumatic heart disease. A validity study was accomplished by randomly inserting 34 cases of known organic heart disease among 2,525 children in one school. Thirty-one of these 34 cases (91.2 per cent) were detected; two of the three cases missed had aortic insufficiency with highpitched grade II murmurs. It is concluded that this tape-recording procedure is a valid, feasible, and efficient method for the detection of organic heart disease in school children.