Estimation of pulmonary/systemic resistance ratios from echocardiographic systolic time intervals in young patients with congenital or acquired heard disease

Abstract

Previous work has shown the positive correlation of echocardiographic right ventricular preejection period/right ventricular ejection time ratio (RPEP/RVET) with pulmonary vascular resistance and pulmonary arterial diastolic pressure obtained at cardiac catheterization. However, the correlation was insufficient to predict pulmonary arterial diastolic pressure or vascular resistance from a given RPEP/RVET ratio. In this study the RPEP/RVET ratio was compared with left ventricular preejection period/ejection time ratio (LVEP/LVET) in 25 patients undergoing cardiac catheterization, and a strong correlation was found between the ratio (RPEP/RVET)/(LPEP/LVET) = R/L and the ratio of pulmonary arteriolar resistance/systemic arteriolar resistance (PAR/RS), especially when R/L was correlated with log10 PAR/RS (r = 0.902). A very high correlation (r = 0.960) was found between R/L and log10 PAR/RS when the group was restricted to patients with a ventricular septal defect or a complete endocardial cushion defect. Regression equations for prediction of PAR/RS have been derived for the various groups.