Contribution of Doppler Atrioventricular Flow Waves to Ventricular Filling in the Human Fetus

Abstract

The normal fetal flow velocity profile across the atrioventricular valves is characterized by an early peak (E), which is related to preload and to active ventricular muscle relaxation, and a higher late peak (A), which is caused by the atrial contraction and also influenced by ventricular compliance. The purpose of this study was to determine how these two elements of ventricular filling change during gestation in both ventricles. A total of 485 normal fetuses from 17 weeks to term were examined by Doppler echocardiography. We measured E and A peak velocities and E/A ratio for both mitral and tricuspid valves. Simple regression analysis was applied to assess possible correlation between Doppler variables and gestational age. Moreover, E and A peak velocities were compared using paired Student's t-test. With the advance of gestation a significant linear increase in the E wave and E/A ratio was found for both mitral and tricuspid valves. The A wave shows little change throughout pregnancy. We found significantly higher Doppler velocities for the tricuspid valve than for the mitral valve. The relationship between the E/A ratios for the two valves and gestational age diverge slightly, with higher values for the mitral E/A ratio. This study shows that the A wave velocity remains constant throughout gestation, suggesting little or no change in ventricular compliance. The E wave is mainly responsible for the change in E/A ratio for both atrioventricular valves during gestation. These findings suggest progressive enhancement of relaxation and elastic recoil, an increase in preload, or both, throughout gestation, rather than a change in myocardial compliance as an explanation for the observed increase in the E/A ratio.

Reference ranges for time‐related analysis of ductus venosus flow velocity waveforms in singleton pregnancies

“…From this point of view, acc‐D corresponds to acc‐E and significant correlations of acc‐D and acc‐E with gestational age may suggest maturation of diastolic myocardial function. Previous studies which reported an increase of the peak velocity of the E‐wave with advancing gestational age are in accordance with our results and support our explanation …”

“…From this point of view, acc-D corresponds to acc-E and significant correlations Previous studies which reported an increase of the peak velocity of the E-wave with advancing gestational age are in accordance with our results and support our explanation. 2,[16][17][18] Two studies have been published previously regarding timerelated analysis of DV-FVW. Gallarreta et al measured 'venous acceleration time', which we defined as acc-S, in normal fetuses.…”

Correlation analysis of ductus venosus velocity indices and fetal cardiac function

“…The DV‐PIV and individual velocity ratios were converted into Z ‐scores using reference ranges derived from a population with documented normal outcome. For the E/A ratio we calculated Z ‐scores from the reference ranges of van Splunder et al between 11 and 16 weeks and the nomogram by Fernández Pineda et al for measurements obtained thereafter. The MPI of the left ventricle was transformed into Z ‐scores utilizing the nomogram of Cruz‐Martinez et al .…”

Atrioventricular Flow Wave Patterns before and after Birth by Fetal Echocardiography

“…The TVI of the right ventricle takes dominance in fetal period which changes to the left ventricle TVI dominance in neonatal period. Fernández Pineda et al9) demonstrated that E and E/A values show a significant linear increase in both mitral and tricuspid valves while A value has no variation during the gestational period. Doppler velocity through tricuspid valve is higher than that through mitral valve.…”