Human fetal tricuspid and mitral deceleration time: changes with normal pregnancy and intrauterine growth retardation.

Studies in instrumented adults have shown an association between Doppler echocardiography-derived atrioventricular valve deceleration times and ventricular function. To determine how gestational age affects deceleration time in the tricuspid and mitral valve, pulsed Doppler ultrasonographic examinations were performed in 54 normal human fetuses. In addition, 26 fetuses with growth retardation and the absence of end-diastolic Doppler velocities in the umbilical artery were examined. Measurements were obtained from strip chart recordings; between three and five beats were used to obtain an average heart rate, ratio of peak velocity at atrial contraction to peak velocity in early diastole, and deceleration time in early diastole. Deceleration times increased during gestation from 86 +/- 27 to 116 +/- 18 msec in the tricuspid valve and from 98 +/- 25 to 132 +/- 21 msec in the mitral valve. Fetuses with growth retardation and the absence of end-diastolic Doppler velocities in the umbilical artery had longer deceleration times than those of normal fetuses (p less than 0.01). The increase in deceleration time across both atrioventricular valves in normal fetuses may be related to heart rate, an increased rate of ventricular relaxation, or an increase in ventricular compliance. The fetuses with intrauterine growth retardation and the absence of end-diastolic velocities in the umbilical artery have abnormally increased deceleration times; in the abnormal fetus this may be a result of impaired ventricular relaxation or decreased ventricular compliance.