Assessment of left ventricular global and regional longitudinal function in fetus using velocity vector imaging

Objective To measure the left ventricle global and segmental longitudinal strain, strain rate, and peak velocity in normal fetuses using velocity vector imaging (VVI) for the assessment of the left ventricular function. Methods Detailed prenatal echocardiographic examinations were performed in 53 normal fetuses. Digital dynamic four-chamber views were collected and analyzed offline. In the four-chamber view, the interventricular septum and left ventricular lateral wall were divided into basal, middle and apical segments, in a total of six segments. Endocardial tracing began at the edge of the anterior mitral valve annulus, along endocardium of interventricular septum, extended to the ventricular apex, and returned to posterior mitral valve annulus along lateral ventricular wall edge. The global and segmental longitudinal strain, strain rate and peak velocity of the interventricular septum and left ventricular lateral wall were measured, the global function was calculated by an average of all segments. Segmental measurements were compared to global results. Results Fifty-three fetuses were enrolled in this study, and the VVI analysis was successful in 49, the success rate was 92.4%. The global left ventricular strain was –13.72%±3.99%, and the strain rate was –2.59±0.44/s and 2.43±0.38/s in systole and diastole respectively. No difference was found between segmental and global ventricular strain and strain rate. The left global ventricular peak velocity was 1.68±0.46cm/s and 1.51±0.41cm/s in systole and diastole respectively. The peak segmental velocity in systole and diastole decreased from the base of interventricular septum and lateral wall to ventricular apex. The global left ventricular peak velocity was significantly different from the peak velocity of apical and basal segments (P