1283 RIGHT VENTRICULAR DYSFUNCTION IN PREMATURE INFANTS

Abstract

The purpose of this study was to determine the relationship of pulmonary systolic time interval ratios (PSTI) to ductal shunting (DS) in premature infants. Echocardiograms were obtained on 102 infants (Wt <2.4 Kg) at 1-28 days of age (mean 5.6) because of symptomatic DS. They were divided into 2 groups based on PSTI (Group I<.35, n=57; Group II> .35, n=45). They were compared for age, weight, surface area, chamber dimensions, aortic root size, left ventricular time intervals and contractility. No significant differences were found except that Group II infants were younger. Echocardiographic left heart volume overload was found in 40/57 (70%) of Group I and 33/45 (73%) of Group II infants. No differences in the incidence of DS, chamber size or left ventricular function were seen with elevated PSTI's. Elevated pulmonary vascular resistance was expected to reduce DS. The lack of an effect of high PSTI's on DS suggests that the high PSTI's were not reflecting increased pulmonary resistance. Elevated PSTI's in premature infants with a patent ductus arteriosus are likely to be due to right ventricular dysfunction from coronary insufficiency or hypoxia.