Echocardiographic Assessment of the Vibratory Innocent Murmur in Children: a Case-Control Study

Vibratory innocent murmur is the most common precordial innocent murmur in children. The mechanism of vibratory innocent murmur is still unclear. The aim of this study is to learn the mechanism of the vibratory innocent murmur. The prospective cross-sectional study was conducted using 32 children who had the vibratory innocent murmur (cases) in Chiang Mai University Hospital and 27 normal healthy children (controls). Two-dimension, Doppler, and tissue Doppler echocardiography were performed on each subject to examine the difference between cases and controls. The left ventricular false tendon was present in 84% of cases and 22% of controls (P < 0.001). Left ventricular outflow tract velocity was significantly higher in cases than in controls (P < 0.001). Early diastolic myocardial velocity at the base of the interventricular septum was lower in cases with false tendon than those without false tendon (P = 0.048). No significant difference was found regarding ascending aorta diameter, cardiac output and ejection fraction between the two groups. Left ventricular diastolic function was normal in all cases and controls. The vibratory innocent murmur is associated with the presence of left ventricular false tendon and higher left ventricular outflow tract velocity. The presence of the left ventricular false tendon was somewhat associated with decreased early diastolic myocardial velocity. Normal left ventricular systolic and diastolic function can be used as a reassurance in cases with the vibratory innocent murmur.