Leiva M C, Tolosa J E, Binotto C N, Weiner S, Huppert L, Denis A L, Huhta J C
Department of Obstetrics and Gynecology, Pennsylvania Hospital, Philadelphia 19107, USA.
Ultrasound Obstet Gynecol. 1999 Sep;14(3):169-74. doi: 10.1046/j.1469-0705.1999.14030169.x.
To describe fetal cardiac and hemodynamic development in the first trimester of pregnancy.
Forty-eight pregnancies were prospectively studied with transvaginal ultrasound and color Doppler. Fetal heart rate and size were documented together with the presence of inflow and outflow wave-forms and valve signals.
Heart rate and size showed a positive correlation with gestational age. At 6 weeks of gestation, 20% of the cardiac cycle was occupied by the isovolumic contraction time (ICT); the isovolumic relaxation time (IRT) occupied 16% and remained unchanged, while the ICT progressively shortened and was not measurable after 12 weeks. The peak inflow velocities had changed from monophasic to biphasic by 10 weeks of gestation. At 7 weeks of gestation, semilunar valves were detected in 10% of examinations and the atrioventricular valves in 3%. The detection rate for both valves at 12 weeks was > or = 90%. In pregnancies that miscarried, the detection rate for both was < 25%.
The Doppler signals that characterize the heart during the first trimester suggest effective heart compliance by 12 weeks. Normal valve development can be inferred from non-invasive Doppler recordings.
描述妊娠早期胎儿心脏及血流动力学发育情况。
采用经阴道超声和彩色多普勒对48例妊娠进行前瞻性研究。记录胎儿心率、大小以及流入和流出波形及瓣膜信号的情况。
心率和大小与孕周呈正相关。妊娠6周时，等容收缩时间（ICT）占心动周期的20%；等容舒张时间（IRT）占16%且保持不变，而ICT逐渐缩短，12周后无法测量。妊娠10周时，峰值流入速度从单相变为双相。妊娠7周时，10%的检查中检测到半月瓣，3%的检查中检测到房室瓣。12周时两种瓣膜的检出率均≥90%。在流产的妊娠中，两种瓣膜的检出率均<25%。
妊娠早期表征心脏的多普勒信号表明到12周时心脏顺应性良好。可从无创多普勒记录推断瓣膜发育正常。
