Echocardiographic assessment of left ventricular function. Investigation of infants, children and teenagers without heart disease.

Echocardiography was used to study left ventricular function in 75 infants, children and teenagers without heart disease. Normal values for echocardiographic parameters of left ventricular contractility were obtained and are presented in Tables. Systolic time intervals were measured from aortic cusp echoes and the normal range and correlation to heart rate and age are given. Computer analyses of echocardiograms from the left ventricle and the anterior mitral leaflet were done and normal values for the instantaneous velocities thus derived are given. To test the normal variation of left ventricular function with time 12 children were examined repeatedly during 1 wk. 95% tolerance limits for the variation of the different functional parameters are given. To test the reproducibility of the echocardiographic measurements 11 children with various forms of heart disease were examined consecutively by two different observers and the 95% tolerance limits for the difference between measurements were calculated.