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Echocardiographic quantification of fetal cardiac output (CO) aids clinical decision-making in the management of various cardiac and extracardiac diseases. Small variability in measuring semilunar valve dimension significantly reduces the reproducibility of the calculated CO. The authors propose minute stroke distance or velocity-time integral (VTI) as a more reproducible measure reflecting fetal ventricular systolic function. The aim of this study was to test the hypothesis that right and left ventricular minute VTI increase predictably with estimated fetal weight and are more reproducible than CO.Five hundred seventy-one singleton fetuses without cardiovascular pathology between 16 and 36 weeks' gestation were reviewed retrospectively. Twenty-two fetuses with pathology resulting in low- or high-CO states were also assessed for comparison. VTI was measured in both ventricular outflow tracts at the level of the semilunar valve, excluding a Doppler insonation angle of30°. Heart rate, semilunar valve dimension, and VTI determined minute VTI and CO. Inter- and intrarater variability were evaluated in a random 10% subset.Minute VTI and CO measurements were feasible in 67% to 89% of fetuses in this retrospective study. Minute VTI and CO increased with estimated fetal weight nonlinearly (R = 0.61-0.94). The mean inter- and intrarater variability for VTI, 6% and 5.7%, were significantly less than for CO, 25% and 23.7% (P .001 for all).Minute VTI is an easily measured, highly reproducible method of quantifying fetal ventricular systolic function. Variability in calculated CO from valve measurement differences is minimized by solely using VTI. Nomograms of minute VTI provide an efficient and precise assessment of fetal systolic function and may be used to track fetuses in disease states with low or high CO.

Patients with ventriculoarterial discordance, such as congenitally corrected and d-transposition of the great arteries, may undergo a morphologic left ventricular (LV) training strategy consisting of surgical pulmonary artery band (PAB) placement and subsequent anatomic repair to establish ventriculoarterial concordance. The purpose of this study was to characterize morphologic LV function and deformation longitudinally using speckle-tracking strain analysis in patients with ventriculoarterial discordance who underwent LV training.Twenty-nine patients (12 with d-transposition of the great arteries and 17 with congenitally corrected transposition of the great arteries) who underwent LV training with PAB placement were evaluated retrospectively. LV ejection fraction and global and regional longitudinal strain and strain rate were measured before and 7 ± 5 days after PAB placement and subsequent anatomic repair.PAB placement caused reductions in the mean LV ejection fraction from 76.1 ± 10.2% to 66.7 ± 7.8% (P.001), in mean global strain from -17.7 ± 9% to -13.3 ± 7.5% (P = .01), and in mean lateral wall strain from -23.3 ± 12.8% to -17.5 ± 10.3% (P = .01). After anatomic repair (a median of 21 months after PAB placement; range, 0.5-104 months), mean LV ejection fraction decreased further from 63.3 ± 8.6% to 52.4 ± 14.9% (P.05). Mean global strain declined from -17.6% ± 4.4 to -12.6 ± 4% (P = .01), and mean lateral wall strain decreased from -18.2 ± 11.4% to -12.6 ± 5.3% (P = .04).In patients with ventriculoarterial discordance undergoing PAB placement for LV training and anatomic repair, the morphologic left ventricle demonstrated decremental systolic function and global longitudinal deformation acutely. Frequent functional assessment is warranted to understand long-term myocardial mechanics in these patients.