[The fetal systolic time intervals as an indicator of fetal hemodynamics--physiologic changes of the fetal systolic time intervals with fetal growth].
The fetal systolic time intervals (fetal STIs) with advancing fetal age were analysed in normal fetuses by means of the fetal STIs monitoring system which we had devised. The following results were obtained: The electro-mechanical delay (EMD), isometric contraction time (ICT) and pre-ejection period (PEP) were gradually prolonged during gestation; they were markedly prolonged after 32 weeks' gestation. The ventricular ejection time (VET) and VET corrected by heart rate (VET425) were shortened with advancing fetal age. The ejection index (PEP/VET425) and %PEP were increased, especially after 32 weeks' gestation. The PEP showed a high correlation with the ICT. The VET had a negative correlation with fetal heart rate between 36 and 40 weeks' gestation. The mean values (+/- S.D.) of these parameters between 36 and 40 weeks' gestation were as follows: EMD = 43.0 +/- 1.3 msec, ICT = 29.2 +/- 3.0 msec, PEP = 72.4 +/- 3.6 msec, %PEP = 17.1 +/- 1.4%, VET425 = 177.1 +/- 3.9 msec and PEP/VET425 = 0.407 +/- 0.022. The parameters were not correlated with birth weight. These results suggest marked fetal hemodynamic changes after 32 weeks' gestation, and these parameters may be used to indicate functional adaptation of the cardiovascular system with fetal growth.
D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005333:Fetus / Q000502:physiology*; D006128:Growth; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D009200:Myocardial Contraction; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D013599:Systole