Left ventricular diastolic function during normal pregnancy: assessment by spectral tissue Doppler imaging.
OBJECTIVE
Tissue Doppler imaging (TDI) is an echocardiographic technique for assessing the diastolic function that is relatively independent of preload. Since loading conditions change significantly during pregnancy, a load-independent technique will give a more accurate assessment of diastolic function in pregnant women. The aim of this study was to evaluate maternal diastolic function using tissue Doppler imaging.


METHODS
This was a prospective observational study on 35 healthy pregnant women. M-mode, transmitral inflow (peak transmitral flow velocities during early diastole (E wave) and atrial contraction (A wave)) and TDI studies (peak myocardial velocities during early diastole (Em wave), during atrial contraction (Am wave) and peak systole in ejection phase (Sm)) were performed in each trimester and postpartum. The differences in variables between trimesters were analyzed.


RESULTS
The peak transmitral inflow velocity during early diastole (E wave) was significantly decreased during the third trimester and postpartum. The peak flow velocity during atrial contraction (A wave) was increased in the second trimester, but decreased again in the third trimester and postpartum period. As a result, the E/A ratio progressively reduced as pregnancy advanced. TDI showed that peak myocardial velocities during early diastole (Em) tended to increase during the second trimester, and then decreased significantly in the third trimester or postpartum period. The peak myocardial velocities during atrial contraction (Am) increased significantly with advancing gestational age. As a consequence, both Em/Am and E/Em ratios decreased significantly throughout pregnancy.


CONCLUSIONS
This study demonstrates the changes in myocardial relaxation velocity throughout pregnancy. Because of its advantage of being relatively load-independent, TDI may be a useful non-invasive technique for monitoring maternal cardiac function in high-risk pregnancies to detect the early signs of cardiac failure and to prevent further deterioration with prompt interventions.
Fok
W Y
WY
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong. angelwyfok@yahoo.com
Chan
L Y
LY
Wong
J T
JT
Yu
C M
CM
Lau
T K
TK
D003971:Diastole; D018619:Echocardiography, Doppler, Pulsed / Q000295:instrumentation / Q000379:methods*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000502:physiology*; D011264:Pregnancy Trimesters; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000295:instrumentation / Q000379:methods*; D016277:Ventricular Function, Left / Q000502:physiology*