Respiratory distress syndrome: echocardiographic assessment of cardiovascular function and pulmonary vascular resistance.

Echocardiograms were performed for 82 preterm infants comprising 22 normal infants, 29 with mild respiratory distress syndrome (RDS), and 31 with severe RDS. Left ventricular systolic time intervals were measured from aortic valve echograms and right ventricular systolic time intervals from pulmonic valve echograms. Left ventricular performance seemed to be altered early in postnatal adaptation of preterm infants, but played no demonstrable role in the outcome of RDS. The right ventricular preejection period/right ventricular ejection time (RPEP/RVET) ratio was prolonged in 17 out of 31 patients with severe RDS, consistent with increased pulmonary vascular resistance or right ventricular dysfunction. Prolonged RPEP/RVET identified a subgroup with increased mortality and morbidity.