Lim Y L, Walters W A
Am J Obstet Gynecol. 1976 Sep 1;126(1):26-32. doi: 10.1016/0002-9378(76)90459-2.
Systolic time intervals were measured in 10 nonpregnant, 37 normotensive, and 18 hypertensive pregnant women in both supine and lateral positions. With all the subjects in the supine position, left ventricular ejection time (LVET) was shortened; the pre-ejection period (PEP) lengthened, and the PEP/LVET ratio increased in normotensive late pregnancy compared with the nonpregnant state. Similar alterations in systolic time intervals were observed in hypertensive women in both early and late pregnancy in the supine position. In normotensive women in early pregnancy, alterations in systolic time intervals were inconclusive. When normotensive women in late pregnancy were turned from the supine into the left lateral position, a prolongation of LVET and a decrease in the PEP/LVET ratio were observed. When hypertensive women in late pregnancy adopted the left lateral position, no significant alterations in systolic time intervals occurred. Isovolumetric contraction time (ICT) was prolonged only in the hypertensive pregnant women in the supine position. The study suggests that left ventricular performance is diminished in normotensive women in late pregnancy when supine but improves when they adopt the lateral position. In addition, hypertensive pregnant women show evidence of diminished left ventricular performance which is not improved in late pregnancy by assumption of the left lateral position.
对10名未怀孕女性、37名血压正常的孕妇和18名高血压孕妇在仰卧位和侧卧位时的收缩期时间间期进行了测量。所有受试者处于仰卧位时，与未怀孕状态相比，血压正常的妊娠晚期女性左心室射血时间（LVET）缩短；射血前期（PEP）延长，PEP/LVET比值增加。仰卧位时，妊娠早期和晚期的高血压女性收缩期时间间期也出现类似变化。妊娠早期血压正常的女性，收缩期时间间期的变化尚无定论。妊娠晚期血压正常的女性从仰卧位转为左侧卧位时，观察到LVET延长，PEP/LVET比值降低。妊娠晚期高血压女性采取左侧卧位时，收缩期时间间期无显著变化。仅仰卧位的高血压孕妇等容收缩时间（ICT）延长。该研究表明，妊娠晚期血压正常的女性仰卧时左心室功能降低，但采取侧卧位时功能改善。此外，高血压孕妇显示出左心室功能降低的迹象，妊娠晚期采取左侧卧位并不能改善这种情况。
