Ventricular filling patterns of the right and left ventricles in normally grown fetuses: A longitudinal follow-up study from early intrauterine life to age 1 year

OBJECTIVE: Our goal was to determine the effects of advancing age on the Do ppler diastolic filling indexes from early gestation to 1 year of life. STUDY DESIGN: Seventy-nine fetuses were studied. Initial Doppler studies we re started at about the 16th week of gestation and repealed every 4-6 weeks until term, on postnatal day 1 and 2, and at ages 6 weeks, 6 months, and 1 2 months. A minimum of 5 returning Doppler waveforms were traced and analyz ed for(1) peak early Row velocity, (2) late peak atrial flow velocity, (3) total area area under the curve, and (4) the acceleration and deceleration phases. The stiff ness of the ventricles was estimated. Slopes of the curve s for each of the parameters were analyzed for differences across time peri ods and between right and left ventricles. RESULTS: (1) Heart rate significantly decreased with advancing age. (2) Lef t ventricular and right ventricular peak early flow velocity and late peak atrial flow velocity significantly increased during fetal life but not duri ng the ist year. (3) Atrial predominance was found during fetal life but no t during the first year. (4) The deceleration phase of filling significantl y increased during the fetal period. (5) Ventricular stiffness progressivel y decreased during the fetal period. (6) Increased ventricular filling shif ted from a right-sided dominance in utero to a left-sided dominance after b irth. CONCLUSIONS: (1) Fetuses have stiffer fetal ventricles than neonates. (2) T he diastolic filling patterns in normally grown fetuses mimic those of the diseased adult heart. We speculate that this maturation process may be affe cted in fetuses born prematurely or small for gestational age.