Study on fetal circulation using Doppler signal and pulse waveforms

点击翻译按钮获取中文摘要

(1) Study on fetal isovolumetric contraction time: To study the fetal cardiac isovolumetric contraction time (ICT) in normal and complicated pregnancies with placental vascular disease, ICTs were measured in 160 normal fetuses and 55 complicated pregnancies. In normal pregnancy, the ICT remained constant with gestation and fetal heart rate. A strong correlation between prolonged ICT duration and abnormalities in the perinatal course, indicating that a prolonged fetal ICT predicts adverse outcome in the presence of placental vascular disease.(2) Study on fetal pulse waveform in the descending aorta: Pulse waveforms of the fetal descending aorta were obtained using an echo-tracking system to clarify the gestational age-related changes and the usefulness for detecting cardiac dysfunction. Peak-systolic (PSD) and end-diastolic diameter (EDD), pulse amplitude (Amp) and Amp:EDD ratio, calculated from the pulse waveforms, were adopted for analysis. In 196 normal fetuses after 20 weeks, the PSD, EDD and Amp increased, and Amp:EDD ratio decreased linearly with advancing gestation. The 19 fetuses with suspected cardiac dysfunction were divided into healthy and altered cardiac function subgroups, according to the values of fractional shortening and preload index. Of these, 7 fetuses with cardiac dysfunction had significantly higher incidence of low Amp (p<0.01) and Amp:EDD ratio (p<0.001) than remaining 12 fetuses with normal cardiac function. The pulse waveform analysis in the fetal descending aorta proved useful for detecting fetal cardiac dysfunction in utero.