Doppler echocardiographic studies of diastolic cardiac function in the human fetal heart.

Fetal echocardiography has been used for the noninvasive evaluation of human fetal cardiac anatomy, function, and hemodynamics. The purpose of the present study was to use Doppler echocardiographic methods to measure diastolic flow velocity patterns across the tricuspid and mitral valves in human fetuses during gestation. Fifty normal fetuses, 35 fetuses with intrauterine growth retardation (IUGR), and 30 fetuses of diabetic mothers (DM) were studied. Peak flow velocities during early diastole (peak E wave) and peak flow velocities during atrial contraction (peak A wave) were measured, and the peak E/A ratio was calculated. The peak E/A ratio of the left ventricle in fetuses increased gradually with increasing gestational age (r = 0.57, p < 0.05), and the peak E/A ratio of the right ventricle in fetuses increased linearly with increasing gestational age (r = 0.48, p < 0.05). In early gestational age, the peak E/A ratios of both the left and right ventricle in fetuses with IUGR and of DM were not significantly different from those in the controls. However, in late gestational age, the peak E/A ratios of both the left and right ventricle in fetuses with IUGR and of DM were significantly smaller than those in the controls. This gradual decrease in the peak E/A ratio during gestation may represent the maturational or developmental alteration of diastolic cardiac properties in utero. Fetuses with IUGR and of DM may have abnormal diastolic cardiac function in later gestation.