Characterization of ventricular myocardial performance in the fetus by tissue Doppler imaging

Background: Clinically useful indices of fetal cardiac function have not been fully delineated for tissue Doppler imaging (TDI). Methods and Results: In the present study, 56 pregnancies between the 17^th and 38 ^th weeks of gestation included 38 normal fetuses, 6 cases of hydrops fetalis (HF), and 12 of intrauterine growth retardation (IUGR). Peak velocity in early diastole (E) was measured by pulsed-wave Doppler and the peak annular velocities in systole (Sa) and early diastole (Ea) were measured by TDI. The ratio between flow velocity and annular velocity in early diastole (E/Ea) and the ratio of the Sa of right ventricle to that of the left ventricle (RVSa/LVSa) were estimated. In all fetuses with HF, LVSa was <2 cm/s and LVE/Ea was >13. RVSa/LVSa in the HF group was significantly higher than that in the normal group, and RVSa/LVSa in the IUGR group was significantly lower than that in the normal group. Conclusions: A combination of low LVSa and high LVE/Ea shows reduced global myocardial performance of the LV, and would be one of the useful indices for quantitative assessment in high-risk pregnancies. Changes in the RVSa/LVSa ratio may reflect afterload changes in both ventricles and compensatory cardiovascular mechanisms occurring during the process of placental insufficiency and heart failure.