Effect of patent ductus arteriosus on Doppler-derived right ventricular systolic time intervals.

Right ventricular systolic time intervals (RVSTI) and noninvasive Doppler-derived pulmonary blood flow were measured before and after surgical ductus ligation in 18 otherwise healthy infants and children who were older than 3 months of age. Right ventricular preejection period (PEP) and the ratio of preejection period and right ventricular ejection time (PEP/RVET), both corrected or uncorrected for heart rate, decreased significantly following surgery (PEP 71 +/- 14 vs. 50 +/- 13, p < 0.001 and PEP/RVET 0.29 +/- 0.06 vs. 0.21 +/- 0.05, p < 0.001). The volume of pulmonary blood flow correlated with PEP/RVET (r = 0.48, p = 0.003). The magnitude of the change in pulmonary blood flow correlated with the change in PEP/RVET (r divided by 0.56, p = 0.016). The velocity of circumferential fiber shortening (VCFc) increased after surgery, but not significantly. We speculate that patent ductus arteriosus has a similar effect on right ventricular performance when other congenital heart defects are present.