Systolic time intervals and impedance cardiogram in pregnant and toxemic women.
STI measurements and impedance cardiography were carried out during gestation and post partum in 231 cases. In normal pregnant women, prolongation of the Q-I interval, isometric contraction time (ICT), preejection period (PEP) and shortening both of the Q-II interval and ejection time (ET) were all marked in late stages of pregnancy. Mean values for stroke volume (SV), cardiac output (CO) and cardiac index (CI) were at the maximum at 16-23 weeks of pregnancy, and then fell in the antepartum period. The total peripheral resistance (TPR) at 16-23 weeks of pregnancy was lower than in other periods. In the postpartum period, the heart rate was lowered, and the Q-II interval and ICT were prolonged. In toxemic pregnancy, SV, CO and CI were lower than those of the normal group and various changes in STI were more apparent than those of non-toxemic pregnants in the supine position. By the postural change from supine to left lateral in toxemia, the improvement in STI was not as good as in the normal pregnant group and, moreover, SV and CO were decreased and TPR was increased. These results suggest that in toxemic pregnancy the left ventricle might be less complaint and less sensitive to the increase in venous return.
D000328:Adult; D002302:Cardiac Output; D002307:Cardiography, Impedance; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D009200:Myocardial Contraction; D010992:Plethysmography, Impedance; D011225:Pre-Eclampsia / Q000503:physiopathology*; D011247:Pregnancy; D013318:Stroke Volume; D013599:Systole