Accuracy of analog telephonic stethoscopy for pediatric telecardiology

Objective. Wide-bandwidth electronic stethoscopy is reliable and accurate for pediatric telecardiology. We tested a much less expensive and more convenient system for the same purpose, a narrow-bandwidth telephonic stethoscope (TS). Methods. Seventy-six consecutive patients (mean age: 10.0; standard deviation: 6.5 years) in a pediatric cardiology outpatient clinic were studied. One pediatric cardiologist examined the patients with his acoustic stethoscope (AS); a second examined them within a few minutes using a remote TS. A nurse placed the TS chest piece as directed by the remote examiner via intercom, but neither video examination nor conversation with the parent/patient were permitted. Examiners independently recorded the stethoscope findings for all heart sounds, all murmurs, and heart disease (present/absent). TS accuracy was indexed using the kappa statistic for TS/AS agreement and for TS agreement with auscultatory findings predicted from echocardiographic (echo) studies (N = 49). Results. TS/AS agreement was satisfactory for presence/ absence of heart disease (kappa = 0.63) and for organic, functional, vibratory, diastolic aortic, and diastolic pulmonic murmurs (kappa range: 0.65-0.75). For other specific murmurs and all heart sounds, TS/AS agreement was either unsatisfactory (kappa less than or equal to 0.60) or indeterminate because prevalence was 0. TS-AS agreement improved when the TS was used by the more-experienced TS examiner and with patients at least 5 years of age. When the older children were examined by the more TS-experienced examiner, the TS-echo comparison yielded kappa = 0.90, raw agreement = 0.96, sensitivity = 0.94, and specificity = 1.00. Conclusions. In pediatric patients, a narrow-bandwidth telephonic stethoscope can accurately distinguish between functional and organic murmurs and thus can detect heart disease. Accuracy is greatest when the instrument is used by an experienced examiner with patients at least 5 years of age.