ALTERATIONS IN LEFT AND RIGHT VENTRICULAR SYSTOLIC AND DIASTOLIC FUNCTION IN THE HUMAN FETAL HEART DURING SUPRAVENTRICULAR ARRHYTHMIAS: DOPPLER AND M-MODE ECHOCARDIOGRAPHY.

Ultrasound techniques were used to examine 25 fetuses with supraventricular arrhythmias, between 22 and 40 weeks gestational age. A 256-element 3. 5 MHz linear array scanner was used to establish fetal lie, location of the placenta, and amount of amniotic fluid. Measurements were obtained of biparietal and abdominal diameters and femur lengths. Simultaneous M-mode echocardiography was performed during the cardiac examination. Doppler was performed with a 3. 5 MHz pulsed Doppler sector scanner. It was shown that post-extrasystolic potentiation is present after premature atrial contractions in the human fetal right ventricle and left ventricle. The flow velocity patterns during these changes in rhythm indicate an increase in peak flow velocity with atrial contraction, with the premature atrial contraction followed by a decrease during the compensatory pause.