A Quantitative Study Of Diastolic Ventricular Function In The Normal Fetuses By M-mode Color Doppler Echocardiography

Objective:To establish the reference ranges of color M-mode propagation velocity (Vp) in second and third trimester fetuses. The relationship between Vp and gestational age was assessed.Methods:One hundred ninety-two normal fetuses from 21 to 39 weeks of gestation were recruited in the study. Color M-mode Vp of the right ventricle (RV) and left ventricle (LV) were measured, and early diastolic inflow velocities (E) of the atrioventricular valves were assessed by pulsed-wave Doppler. The ratio of E/Vp was calculated. These data were compared to that of 52 normal neonatus aged 2-5 days.Results:In normal fetuses, the RV Vp was (14.8±4.7) cm/s with a range of 11.2～37.4cm/s and the LV Vp was (24.3±6.7) cm/s with a range of 5.6～24.0cm/s. The RV Vp was significantly lower than the LV Vp (P<0.001). The ratio of E/Vp in normal fetuses was 2.84±1.0 for the RV and 1.63±0.64 for the LV. No significant changes in the fetal Vp and the ratio of E/Vp were seen with advancing gestational age (P> 0.05). Normal values of Vp in fetuses were significantly lower than those of 52 normal neonatus in whom the RV Vp was 31.8±6.1 cm/s and the LV Vp was 43.6±6.9 cm/s. In addition, the ratio of E/Vp in fetuses were significantly higher than those of neonatus for either ventricle (RV 1.51±0.40 and LV 1.19±0.30). Conclusions:Vp of fetuses from 21 to 39 weeks of gestation can be quantitatively measured by using Color M-mode echocardiogram. The reference ranges provide a reliable quantitative standard to estimate diastolic ventricular function of fetuses, which may be clinically useful in prenatal detecting early cardiac failure.