Digital phonocardiography as a screening tool for heart disease in childhood

To evaluate the performance of experienced cardiologists by use of digital phonocardiography for the correct identification of heart disease and innocent murmurs in children.

Two independent paediatric cardiologists blindly evaluated 83 digital phonocardiograms obtained from consecutive paediatric cardiology outpatients. Each observer had to document the presence and characteristics of murmurs (intensity, quality, location), the presence of additional abnormal auscultatory findings (systolic click, second heart tone abnormalities) and whether he would recommend echocardiography (ECHO). The accuracy of their diagnoses was tested against the ECG diagnosis within two severity levels of heart disease.

Twenty-three out of 24 cases (95.8%) with moderate-to-severe heart defects and 12 to 13 out of 19 cases (63.2%-68.4%) with trivial-to-mild heart defects were correctly identified by phonocardiography. Additionally, 37 to 38 out of 40 cases (92.5%-95.0%) without ECHO evidence of heart disease were correctly interpreted as having innocent murmurs. The level of agreement between the two observers was substantial regarding their recommendations for ECHO (kappa, kappa=0.83) and in identifying abnormal murmurs (kappa=0.78).

Evaluation of digital phonocardiography by experienced cardiologists could allow for correct identification of moderate-to-severe forms of heart disease while preventing the majority of children with innocent murmurs from unnecessary referral.