Examination of fetal coronary sinus blood flow by Doppler ultrasound

The aim of this study was to demonstrate coronary sinus blood flow in the human fetus by color Doppler imaging and pulsed wave Doppler sonography and to determine the feasibility of using Doppler ultrasound for routine investigation. Visualization of the coronary sinus blood flow by color Doppler imaging was attempted in 84 fetuses with appropriate growth and normal cardiac anatomy, and in which right or left lateral four-chamber views could be obtained (median gestational age, 32 + 5 weeks). After successful identification, examination of the flow velocity waveform and measurement of peak blood flow velocities by pulsed wave Doppler were attempted. Detection of coronary sinus blood flow by color Doppler imaging was possible in 48 fetuses (57.1%) at a median gestational age of 30 + 3 weeks. Pulsed wave measurements were successful in only 11 fetuses (13.1%) (median gestational age, 34 + 2 weeks). The flow velocity waveform is triphasic with antegrade flow towards the right atrium during systole and diastole and reverse flow during atrial contraction. Peak blood flow velocities during diastole were higher (median, 0.38 m/s) than during systole (median, 0.18 m/s); median peak velocity during atrial contraction was -0.05 m/s. Measurement difficulties were due to small fetal size and interference caused by intra-atrial blood flow and/or atrioventricular valvular movement. Demonstration of coronary sinus blood flow by color Doppler imaging is possible in the human fetus. However, pulsed wave Doppler measurements are infrequently obtained, making this study for routine assessment of myocardial blood flow unfeasible.