[Echocardiographic investigation of the left ventricular outflow tract in healthy children (author's transl)].

The width of the left ventricular outflow tract was measured in the echocardiograms at the beginning and the end of the systole in 80 healthy children ranging from 3 to 16 years. The values were referred to the body surface area and the heart volume which was estimated by mean of X-ray. The regression lines as well as the confidence levels of 95 per cent are marked. It becomes obvious that the dispersion of the data related to the heart volume is less than that related to the body surface area. The width of the left ventricular outflow tract with reference to the heart volume and the body surface area resp. shows in relation to the heart volume and the body surface area resp. an exponential behaviour, i.e. in the growing heart the outflow tract decreases in relation to the two parameters. The narrowing of the outflow tract from start to end of the systole is about one third.