Evaluation of Myocardial Function According to Early Diastolic Intraventricular Pressure Difference in Fetuses

Background: Intraventricular pressure difference (IVPD), the diastolic suction during early diastole, is known as a useful marker of myocardial diastolic function in adults with different heart diseases, but there are no studies of fetal IVPD. The aim of this study was to determine whether IVPD exists and changes prenatally and whether IVPD correlates with preexisting parameters to evaluate fetal cardiac diastolic function and ventricular dominance.

Methods: Cross-sectional study data (stroke volume, fetal cardiac output, E/A ratio, and myocardial performance index) from 117 healthy fetuses at 17 to 36 weeks of gestation were retrospectively evaluated. The total IVPD was calculated using Euler's equation with color M-mode data. Segmental IVPD was evaluated as apical, mid, and basal IVPDs.

Results: The total IVPD in the right ventricle and left ventricle significantly increased in late gestation compared with that in different fetuses studied at midgestation (right and left ventricles, ρ = 0.813 and ρ = 0.895, respectively; P < .001). In both ventricles, the apical IVPD percentage, but not basal or mid IVPD, significantly increased at late gestation compared with that in different fetuses studied at midgestation. Both stroke volumes were correlated with IVPD (right and left ventricles, ρ = 0.796 and ρ = 0.784, respectively; P < .001). Although myocardial performance index in the left ventricle did not show a significant correlation with IVPD, the E/A ratio had a very weak correlation with IVPD (right ventricle, ρ = 0.576, P < .001; left ventricle, ρ = 0.338, P < .01).

Conclusions: IVPD has been proved to exist in both ventricles during the fetal stage. The total IVPD increased in late gestation, and the ventricular length increased because of increased apical IVPD in both ventricles. Furthermore, the increase of IVPD in both ventricles was correlated with stroke volume and, accordingly, cardiac output. Left ventricular dominance in IVPD from the fetal stage may offer interesting insight into fetal cardiac development.