Cardiovascular changes in pregnancy evaluated by two-dimensional and Doppler echocardiography

During pregnancy significant cardiovascular changes occur. To study these anatomic and physiologic changes we performed two-dimensional and Doppler echocardiography in 28 women during the third trimester (34.4 +/- 1.9 weeks) of pregnancy and then again after delivery (7.8 +/- 2.2 weeks). Fourteen nonpregnant age- and sex-matched subjects served as controls. Left ventricular diastolic and systolic dimensions were similar among pregnant, postpartum, and control subjects. Left atrial area as determined by two-dimensional echocardiography was significantly larger during pregnancy (16.7 +/- 4.0 cm2) compared with measurements postpartum (13.8 +/- 3.1 cm2) and with controls (15.5 +/- 3.5 cm2) (p less than 0.01). Doppler study showed that the ratio of early diastolic flow velocity to late diastolic flow velocity (E/A max) and E/A integral were lower among pregnant subjects (1.3 +/- 0.3, 2.0 +/- 0.5) compared with postpartum subjects (1.6 +/- 0.4, 2.5 +/- 1.5) and controls (1.9 +/- 0.5, 3.0 +/- 0.8) (p less than 0.05). Heart rate was higher among pregnant subjects (84 +/- 10 beats/min) compared with postpartum subjects (70 +/- 16) and controls (69 +/- 13) (p less than 0.05). In summary, in pregnant subjects during late third trimester left ventricular chamber dimensions were similar to these postpartum measurements in control subjects; however, the left atrium is dilated during pregnancy. Although there are significant alterations in Doppler-derived left ventricular diastolic parameters during the third trimester, increased heart rate and a dilated left atrium may explain these findings.