Although heart murmur in children is usually harmless (referred to as innocent murmur), in a small number of cases it is symptomatic of cardiac disease (referred to as pathologic murmur).

A new study finds that disappearance of heart murmur while standing reliably rules out pathologic heart murmurs. Using an acoustic-based, non-electronic stethoscope, researchers at two French universities noted heart sound characteristics of 194 consecutive children referred to paediatric cardiologists for heart murmur, first with patients in the supine (flat on their back) position, and then for at least one minute in the standing position.

After observational data were collected, an echocardiogram was performed to assess the presence or absence of cardiac anomalies that could explain the murmur. Eight-five percent of children (n=164) referred to a cardiologist for heart murmur did not have cardiac disease. 30 children (15 per cent) had an abnormal echocardiogram that explained the heart murmur. Of 100 children (51 per cent) who had heart murmur while supine but not standing, two had an organic murmur and only one required follow-up.

The disappearance of heart murmur while standing, therefore, excluded a pathologic murmur with a high predictive positive value of 98 per cent and a specificity of 93 per cent, but with a poor sensitivity of 60 per cent. In an era of highly technical medicine, physical examination should remain the first step in diagnosis, according to the authors. They conclude that the disappearance of heart murmur in children upon standing is a valuable clinical test to exclude a pathologic cardiac murmur and avoid costly referral to a cardiologist.