Sorensen B, Laursen K, Rasmussen J P, Suadicani B
Acta Obstet Gynecol Scand. 1976;55(5):447-51. doi: 10.3109/00016347609158528.
Hemodynamic changes during the first and third trimester in pregnancy and in the first week of puerperium were evaluated by non-invasive measurements of Systolic Time Intervals (STI) in supine and left lateral position. The Pre-ejection Period (PEP) was found to shorten significantly in pregnancy and the puerperium due to the increased blood volume. The electro-mechanical systole (QS2) and left ventricular ejection time (LVET) were shortened too, while PEP/LVET-ratio was increased in the third trimester due to the mechanical compression of the gravid uterus on the inferior vena cava. A lengthening of QS2 and LVET and a decreased PEP and P/L-ratio were demonstrated in the third trimester in lateral position when the pressure of the enlarged uterus was eliminated. Heart rate (HR) increased in late pregnancy as well as after delivery, while arterial blood pressure (BP) only underwent minor changes. Employment of the STI seems to provide more useful information about the changes cardiac function during gestation than HR and BP does. The measurements of STI can be repeated without any risk or inconvenience to the patients.
通过对仰卧位和左侧卧位的收缩期时间间期（STI）进行无创测量，评估妊娠早期和晚期以及产褥期第一周的血流动力学变化。由于血容量增加，发现射血前期（PEP）在妊娠和产褥期显著缩短。电机械收缩期（QS2）和左心室射血时间（LVET）也缩短，而在妊娠晚期，由于妊娠子宫对下腔静脉的机械压迫，PEP/LVET比值升高。当扩大的子宫压力消除时，在妊娠晚期的侧卧位中，QS2和LVET延长，PEP和P/L比值降低。心率（HR）在妊娠晚期和分娩后增加，而动脉血压（BP）仅发生轻微变化。与HR和BP相比，使用STI似乎能提供更多关于妊娠期心脏功能变化的有用信息。STI的测量可以重复进行，对患者没有任何风险或不便。
