Tissue Doppler imaging in the normal fetus

Abstract

Tissue Doppler imaging is a new non-invasive method that derives measurements of relaxation velocities directly from the myocardium. This approach to studying myocardial velocities offers the potential for quantitative assessment of diastolic ventricular function. Data on myocardial tissue velocities in normal fetuses have not been established. We measured motion velocities of the left ventricular posterior wall, right ventricular anterior wall, interventricular septum along the long axis in 30 normal fetuses aged 19–38 weeks gestation (mean, 26.3±6.0 weeks). In all fetuses, peak myocardial velocities during early diastole (EW) and atrial contraction (AW) waves were recorded. The mean values for EW, AW, and E/AW of left ventricle were 5.4±1.7, 7.0±1.4 cm/s, and 0.77±0.19, respectively, and those of right ventricle were 5.5±1.5, 7.8±1.5 cm/s, and 0.70±0.14, respectively. The EW (4.1±1.0 cm/s) and the AW (5.3±0.8 cm/s) of the interventricular septum were significantly lower than those of the left and right ventricular walls ( P<0.01). The EW and E/AW of the left ventricular wall increased significantly with increasing gestational age ( r=0.81 and 0.85, respectively, P<0.01). Similar changes were observed in the myocardial velocities of the right ventricular wall. The EW and E/AW of the interventricular septum also increased significantly with age ( r=0.63 and 0.78, respectively, P<0.01). However, AW of the interventricular septum showed little changes. In both ventricles, there were significant correlations between tissue Doppler E/AW and pulsed Doppler E/A (LV, r=0.56; and RV, r=0.60, P<0.01). Assessment of myocardial tissue velocities in fetuses is feasible with tissue Doppler imaging. Age-related alterations in tissue Doppler velocities may suggest age-related maturational changes in diastolic function.