Postsystolic shortening by myocardial deformation imaging as a sign of cardiac adaptation to pressure overload in fetal growth restriction

Background: Fetal growth restriction (FGR) is associated with global adverse cardiac remodeling in utero and increased cardiovascular mortality in adulthood. Prenatal myocardial deformation has not been evaluated in FGR to date. We aimed to evaluate prenatal cardiac remodeling comprehensively in FGR including myocardial deformation imaging. Methods and Results: Echocardiography was performed in 37 consecutive FGR (defined as birthweight <10th centile) and 37 normally grown fetuses. A comprehensive fetal echocardiography was performed including tissue Doppler and 2-dimensional-derived strain and strain rate. Postnatal blood pressure measurement at 6 months of age was also performed. FGR cases showed signs of more globular hearts with decreased longitudinal motion (left systolic annular peak velocity: controls mean 6 cm/s [SD 1.2] versus FGR 5.3 [1]) and diastolic dysfunction (isovolumic relaxation time: controls 44 ms [6] versus FGR 52 [9]). Peak strain and strain rate values of the left ventricle were not significantly different; however, a postsystolic shortening in the basal segment of the septal ventricular wall was observed in 57% of the FGR cases and in none of controls (P<0.001). FGR cases with postsystolic shortening had absence of a hypertrophic response, a poorer perinatal outcome (lower gestational age and birthweight, containing all cases of perinatal mortality [8%]), and higher values of blood pressure. Conclusions: Myocardial deformation imaging revealed a postsystolic shortening in 57% of FGR, which supports increased pressure overload as a mechanism for cardiovascular programming in FGR. Postsystolic shortening was associated with severity and with higher blood pressure postnatally.