Twenty-four Segment Transverse Ventricular Fractional Shortening: A New Technique to Evaluate Fetal Cardiac Function.

OBJECTIVES: Because of various fetal and maternal disease states, this study was conducted to evaluate the fractional shortening of 24 transverse segments distributed from the base to the apex of the ventricular chambers.

METHODS: Two hundred control fetuses were examined between 20 and 40 weeks' gestation. The transverse displacement of the ventricular endocardium during the cardiac cycle was computed by using offline software. From the output of the analysis, 24 end-diastolic and end-systolic segments were measured from the base (segment 1) to the apex (segment 24) of the right and left ventricles, and the fractional shortening was computed: [(end-diastolic length - end-systolic length)/end-diastolic length] × 100. Examples of fetal cardiovascular abnormalities were selected to demonstrate the utility of this technique.

RESULTS: The fractional shortening for each segment was independent of gestational age and fetal biometric measurements. There was no significant difference in fractional shortening for segments 1 to 5 between the right and left ventricles. However, the fractional shortening of the left ventricle was significantly greater (P < .0001) than that of the right ventricle for segments 6 to 24, suggesting that the mid and apical segments of the left ventricle have increased displacement toward the center of the chamber compared to the right ventricle. Fetuses with various cardiac structural abnormalities had abnormal fractional shortening values.

CONCLUSIONS: The fractional shortening of 24 segments of the right and left ventricles provides a comprehensive method to examine the contractility of the ventricular chambers.