Strain rate derived from color Doppler myocardial imaging for assessment of fetal cardiac function

Color Doppler myocardial imaging (CDMI) is a new multigated method that allows direct analysis of myocardial motion. It is superior to pulsed-wave tissue Doppler in its ability to generate new and important indices of myocardial function such as strain, strain rate and tissue tracking. The purpose of this study was to assess the feasibility of CDMI in the fetal heart.

Three normal fetuses of gestational ages 20 + 1, 28 + 1 and 36 + 0 weeks and a fetus of 20 + 3 weeks with aortic valve atresia were studied. Velocity data were acquired from the apical four-chamber view using a Vivid 7 ultrasound platform with integrated software for CDMI and with frame rates around 200/s. Data were post-processed using dedicated software and with the sample area placed at the subvalvular and middle part of the septum and the ventricular walls.

CDMI was feasible in all fetuses. The fetus with aortic valve atresia had severely reduced strain rate of the left ventricular wall.

Using this new technique it is possible to obtain information on the global and regional contractility of the fetal heart and thereby gain new insights into the physiology of the fetal cardiovascular system. CDMI is a promising new method for monitoring at-risk fetuses.