AIMS: To confirm changes in the atrioventricular diastolic flow velocities (peak E, peak A, E/A ratio) with gestational age and to define whether these changes genuinely reflect variations in filling pressure in the fetal heart. METHODS: Fifty normal pregnancies were studied between the 13th and the 37th weeks of gestation. The fetal flow velocity patterns were evaluated by pulsed-wave (PW) Doppler and the annular velocities of the atrioventricular valves by PW-Doppler tissue imaging (DTI). RESULTS: All indexes evaluated (atrioventricular peak flow and annular velocities) correlated significantly with gestational age. This correlation was stronger for the early diastolic indexes (tricuspid E and EA, 0.69 and 0.78; mitral E and EA, 0.61 and 0.77, respectively) and weaker for the end-diastolic indexes (tricuspid A and AA, 0.46 and 0.37; mitral A and AA, 0.45 and 0.39, respectively). Neither mitral nor tricuspid E/Ea ratio changed significantly with gestational age. CONCLUSIONS: The lack of correlation between the Doppler-assessed ventricular filling pressures and gestational age suggests absence of significant changes of ventricular compliance during the second and third trimesters of pregnancy, and a progressive enhancement of active relaxation and/or changes in loading conditions.
AIMS: To confirm changes in the atrioventricular diastolic flow velocities (peak E, peak A, E/A ratio) with gestational age and to define whether these changes genuinely reflect variations in filling pressure in the fetal heart. METHODS: Fifty normal pregnancies were studied between the 13th and the 37th weeks of gestation. The fetal flow velocity patterns were evaluated by pulsed-wave (PW) Doppler and the annular velocities of the atrioventricular valves by PW-Doppler tissue imaging (DTI). RESULTS: All indexes evaluated (atrioventricular peak flow and annular velocities) correlated significantly with gestational age. This correlation was stronger for the early diastolic indexes (tricuspid E and EA, 0.69 and 0.78; mitral E and EA, 0.61 and 0.77, respectively) and weaker for the end-diastolic indexes (tricuspid A and AA, 0.46 and 0.37; mitral A and AA, 0.45 and 0.39, respectively). Neither mitral nor tricuspid E/Ea ratio changed significantly with gestational age. CONCLUSIONS: The lack of correlation between the Doppler-assessed ventricular filling pressures and gestational age suggests absence of significant changes of ventricular compliance during the second and third trimesters of pregnancy, and a progressive enhancement of active relaxation and/or changes in loading conditions.