The echocardiographicmyocardial performance index as descried byTei has been previously shown to be useful in assessment of myocardial function in children with congenital heart defects. Authors established normal values for index of myocardial performance for right and left ventricles in 60 children with innocent murmurs, before assessing 25 patients with ventricular septal defect. The 60 children with normal cardiovascular anatomy and function had a mean left ventricular index of 0.288 (SEM 0.019; 95% CI 0.251 - 0.325) and amean right ventricular myocardial performance index of 0.208 (SEM 0.012; 95% CI 0.183 - 0.232). The mean value of the left ventricular index was 0.431 (SEM 0.03, range 0.176 - 0.701; p < 0.01) in the 25 patients with ventricular septal defects. It was above the95%confidence interval of the control group in 19 children (76%). The meanvalue of the right ventricular index was 0.514 (SEM 0.054, range 0.333 - 1.0; p < 0.001). It was above the upper limit of normal in all 25 children (100%). Therewas no difference in the left and right ventricular indices of the 10 children who required antifailure medication from the 15 asymptomatic children (left ventricle: mean 0.403, SEM 0.035 vs mean 0.450, SEM 0.042; p > 0.5; right ventricle: mean 0.549, SEM 0.084 vs 0.491, SEM 0.073; p > 0.5). Changes of the left and right ventricularmyocardial function, as assessed by themoycardial performance index, may be present in the majority of children with ventricular septal defects. Standard antifailure treatment with diuretics does not influence this incidence of abnormal myocardial function.

        Key words: myocardial function, ventricular septal defect, children