Changes in intracardiac blood flow velocities and right and left ventricular stroke volumes with gestational age in the normal human fetus: a prospective Doppler echocardiographic study.

Abstract

We used Doppler echocardiography to quantitate the changes in intracardiac blood flow velocities and right and left ventricular stroke volumes in 80 normal human fetuses from 19 to 40 weeks gestation. Blood flow velocity spectra across the aortic, pulmonary, tricuspid, and mitral valves were digitized to obtain peak velocities (m/sec) and flow velocity integrals. Aortic and pulmonary diameters were measured at valve level from two-dimensional echocardiographic images and cross-sectional area was calculated assuming a circular orifice. Ventricular stroke volume was calculated as the product of the cross-sectional area of a great vessel and the flow velocity integral through that vessel. The pulmonary arterial and aortic diameters increased linearly with gestational age (r = .82, r = .84), and pulmonary arterial diameter consistently exceeded aortic diameter. There was a positive relationship between stroke volume and gestational age: stroke volume increased exponentially from 0.7 ml at 20 weeks to 7.6 ml at 40 weeks for the right ventricle (r = .87) and from 0.7 ml at 20 weeks to 5.2 ml at 40 weeks for the left ventricle (r = .91). Similar results were obtained for right and left ventricular and combined cardiac outputs. In 44% of the fetuses it was possible to quantitate both right and left ventricular stroke volumes. There was a close correlation between right and left ventricular stroke volumes in these fetuses (r = .96) and right ventricular stroke volume exceeded left ventricular stroke volume by 28%. Flow velocity across the tricuspid and mitral valves was consistently greater during atrial systole (A wave) than during rapid ventricular filling (E wave) (0.52 0.07 vs 0.37 + 0.08 m/sec and 0.45 ± 0.07 vs 0.33 ± 0.06 mlsec). The E/A ratios for the mitral and tricuspid valves were similar throughout the period of gestation studied, indicating equivalent diastolic ventricular function. This study demonstrates that right and left ventricular stroke volumes increase by approximately 10-fold from 20 to 40 weeks gestation in the normal human fetus. It also demonstrates, within the limitations of the equipment, that right ventricular stroke volume exceeds that of the left ventricle, thus confirming right ventricular dominance in utero. Circulation 74, No. 6, 1208-1216 TWO-DIMENSIONAL echocardiographic imaging of the fetal heart has permitted accurate definition of intracardiac anatomy and characterization of the growth patterns of the four cardiac chambers throughout the second and third trimesters.'-Echocardiography has also enabled recognition of cardiac rhythm distur-

Pulmonary vein pulsatility in fetuses of diabetic mothers: prenatal Doppler echocardiographic study

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Fetal cardiac performance in uncomplicated and well‐controlled maternal type I diabetes

“…Techniques of fetal cardiac imaging and measurements have been reported elsewhere [7][8][9][10][11][12][13][14] . All parameters measured were re-analyzed off-line by one of the authors (E.T.J).…”

Cardiac Output and Central Distribution of Blood Flow in the Human Fetus

“…However, the reported ratio of right to left cardiac output ranges from 1.0 to 1.5. [2][3][4][5][6][7] The very few studies that have focused on blood flow through the ductus arteriosus and through the pulmonary circuit in the human fetus have given conflicting results. 4,7 For these reasons, a prospective cross-sectional study that used high-resolution ultrasound equipment, including color Doppler imaging, was performed to establish gestational age-specific reference ranges for left and right cardiac output, combined cardiac output, and volume of blood flow across the ductus arteriosus.…”