Evaluation of Fetal Left Ventricular Size and Function Using Speckle-Tracking and the Simpson Rule.

OBJECTIVES: This study was conducted to evaluate left ventricular (LV) size and function in healthy fetuses and to test a cohort of fetuses at risk for abnormal function using speckle-tracking software.

METHODS: Two hundred control fetuses were examined between 20 and 40 weeks' gestation. With the use of offline speckle-tracking software, the end-diastolic and end-systolic volumes were measured and the following computed: stroke volume (SV), SV per kilogram, cardiac output (CO), CO per kilogram, and ejection fraction. These were regressed against 7 independent variables related to the size, weight, and age of the fetuses. Five fetuses with risk factors for LV dysfunction were examined to sample the validity of the data from the control group.

RESULTS: The R2 values for measurements of the end-diastolic volume, SV, and CO correlated with the 7 independent variables of fetal size and age (0.7-0.78), whereas the SV/kg, CO/kg, and ejection fraction had lower R2 values (0.02-0.1). The measurements were normally distributed (Shapiro-Wilke > 0.5). The 5 fetuses at risk for abnormal LV function had measurements of LV size and function that were consistent with the expected pathologic condition.

CONCLUSIONS: Speckle tracking can provide a comprehensive evaluation of the size and function of the fetal LV.