To assess ventricular diastolic function in fetuses with constriction of ductus arteriosus (DA), 43 fetuses of women receiving indomethacin (100-150 mg/day) were examined with Doppler echocardiography. Ductal constriction was defined as maximal systolic velocity > 140 cm/sec and diastolic flow velocity >30 cm/sec. The constriction DA occurred in 21 fetuses (mean systolic velocity 191±42 cm/sec, mean diastolic velocity 60±34 cm/sec). The other 22 fetuses served as a comparison group. The variables measured were peak velocity during early diastole (E), peak velocity during atrial contraction (A), the ratio of velocity ratio (E/A ratio). The mitral E, A, and E/A ratio in fetuses with ductal constriction showed no significant difference from those in fetuses without ductal constriction. In fetuses with ductal constriction, the tricuspid A increased significantly and E/A ratio decreased significantly compared with those in fetuses without ductal constriction (57±9 vs 50±7 cm/sec, p=0.007, and 0.57±0.10 vs 0.63±0.07, p=0.03, respectively) without changes in E. Serial studies were available in 9 fetuses with ductal constriction during indomethacin administration and after with-drawal for a mean of 24 hours. Both systolic and diastolic ductal flow velocities in all fetuses returned to normal range after discontinuation of indomethacin and the tricuspid A decreased significantly without any significant change in E after discontinuation of indomethacin (Figure).Conclusion: Our study shows that ductal constriction acutely changes Doppler patterns of right ventricular diastolic filling in the human fetus.

figure 1

Figure 1