Comprehensive Evaluation of Fetal Cardiac Ventricular Widths and Ratios Using a 24-Segment Speckle Tracking Technique

This study was conducted to evaluate the 24-segment transverse widths of the right and left ventricles distributed from the base to the apex of the ventricular chambers and compute the right ventricular (RV)/left ventricular (LV) ratios for each segment.

Two hundred control fetuses were examined between 20 and 40 weeks' gestation. Using offline speckle-tracking software, the 24 end-diastolic transverse widths were computed and the RV/LV ratios were regressed against 7 independent variables related to the size, weight, and age of the fetuses. Five fetuses with coarctation of the aorta and 5 fetuses with pulmonary stenosis were examined to exemplify the utility of these measurements.

The 24-segment transverse widths were associated with changes in fetal size, weight, and age. Regression equations were developed to describe these changes with R² values between .5 and .82. The measurements were normally distributed (Shapiro-Wilk > 0.5). The RV/LV ratio for the 24 segments did not strongly correlate (R²  = .001 to -.2) with fetal size, weight, or gestational age. Fetuses with coarctation of the aorta and pulmonary stenosis demonstrated characteristic changes in the 24-segment transverse widths and the RV/LV ratios in the basal (segments 1-8), mid (segments 9-16) and apical (segments 17-24) sections of the ventricles.

The 24-segment transverse widths of the right and left ventricles and the RV/LV ratios provide a comprehensive method to examine the width of the ventricular chambers.