Hunter S, Robson S C
Department of Paediatric Cardiology, Freeman Hospital, Newcastle upon Tyne.
Br Heart J. 1992 Dec;68(6):540-3. doi: 10.1136/hrt.68.12.540.
The first haemodynamic change during pregnancy seems to be a rise in heart rate. Starting between two and five weeks this continues well into the third trimester. Stroke volume increases slightly later than the heart rate and continues throughout the second trimester after an augmentation of venous return and a fall of systemic vascular resistance and afterload. Myocardial contractility is probably slightly increased. During the third trimester there is relatively little change in these cardiac indices. After delivery there is a very early and dramatic reduction in volume loading followed by a return towards normal cardiac output. Structural changes within the heart reflect the volume loading of pregnancy and include dilatation of the valve ring and increase in myocardial thickness. Post partum resolution of the ventricular hypertrophy seems to take longer than the rest of the post partum changes. The resemblance to the cardiovascular changes associated with training and exercise are fascinating and worthy of further study.
孕期的首个血流动力学变化似乎是心率升高。始于孕2至5周，这种情况会持续到孕晚期。每搏输出量的增加略晚于心率，在静脉回流量增加、体循环血管阻力和后负荷下降后，会在整个孕中期持续增加。心肌收缩力可能略有增强。在孕晚期，这些心脏指标变化相对较小。分娩后，容量负荷会非常早且显著地降低，随后心输出量恢复正常。心脏内部的结构变化反映了孕期的容量负荷，包括瓣膜环扩张和心肌厚度增加。产后心室肥厚的消退似乎比产后其他变化所需的时间更长。孕期心血管变化与训练和运动相关变化的相似之处很有趣，值得进一步研究。
