Echocardiographic yield in children when innocent murmur seems likely but doubts linger

The objective of our study was to determine the incidence and nature of heart disease found among children with murmurs clinically ambiguous to an expert examiner. The study was a prospective, blinded evaluation of accuracy of the expert examination using echocardiography as the diagnostic standard. The setting of the study was a pediatric cardiology outpatient department. The study comprised 903 outpatients with heart murmur under 21 years old without prior echocardiography or pediatric cardiology consultation. The intervention was echocardiography as clinically indicated for evaluation of heart murmur of uncertain cause. The outcome measure were a comparison of clinical diagnoses with echocardiographic results. In this clinical population, the presence of heart disease correlated with young age at presentation and with the expert examiner's level of suspicion of heart disease. However, 16 of 187 cases in which specific pathology was unsuspected had disease, and 6 of these 16 have had catheter or surgical intervention. Fourteen of the 16 unsuspected had objective indications for echocardiography and the other 2 were examined to allay anxiety. When evaluating very young outpatients with innocent-sounding murmur or older outpatients with innocent-sounding murmur and disconcerting symptoms, signs, or laboratory results, pediatric cardiologists should have a low threshold for echocardiography. Older outpatients with innocent-sounding murmur seldom have heart disease when anxiety is the only indication for echocardiography.