So-called innocent heart murmurs are thought to be originated by a possible physiologic narrowing of the left ventricular outflow tract, accentuated by a higher contractibility of the myocardium in some children. The aim of our studies was to evaluate this theory with pulsed Doppler echocardiography in order to detect possible local bloodstream disturbances. In a study of 20 children, with or without a vibratory innocent heart murmur no statistical difference was found in either peak-velocity, acceleration or width of the Doppler spectra, read out in an objective computed digital way. The hypothetic location of the origin of the vibratory innocent heart murmur in the left ventricular outflow tract has not yet been confirmed with Doppler echocardiography.