Assessment of the Evolution of Normal Fetal Diastolic Function During Mid and Late Gestation by Spectral Doppler Tissue Echocardiography

Abstract

To establish gestational age-specific reference values in healthy singleton fetuses, we prospectively assessed the evolution of diastolic longitudinal wall-motion velocities by spectral Doppler tissue imaging. Early (Ea) and late diastolic (Aa) peak Doppler tissue imaging velocities were analyzed in 114 fetuses (age range: 14-42 weeks) at the base of right ventricular free wall, ventricular septum, and left ventricular free wall and compared with early (E) and late (A) diastolic peak Doppler inflow velocities. A linear increase in Ea, Aa, and Ea/Aa ratio was documented at all sites with advancing gestation. Likewise, the peak E flow velocities of both atrioventricular valves and the tricuspid peak A flow velocity increased. The ratio of peak E/Ea velocities decreased exponentially as a result of a more rapid increase in Ea than E, to reach a stable E/Ea relationship only in the early third trimester. There was a strong positive correlation between Ea and Aa velocities and gestational age indicating improved diastolic myocardial lengthening with advancing gestation. Reference charts for Doppler tissue imaging velocities were established that will allow identification of fetal diastolic function abnormalities.