Right ventricular function in fetal hypoplastic left heart syndrome.
BACKGROUND
The systemic right ventricle in palliated hypoplastic left heart syndrome (HLHS) has relatively reduced longitudinal compared with circumferential deformation, a pattern of contraction more akin to the normal left ventricle, which presumably improves right ventricular (RV) pumping efficiency. The aim of this study was to test the hypothesis that these changes in the RV contraction pattern in infants with HLHS are present prenatally.


METHODS
Echocardiograms from 48 fetuses with HLHS were retrospectively compared with those from appropriately grown RV and left ventricular controls. Ventricular function was assessed using Velocity Vector Imaging velocity, tissue deformation, two-dimensional echocardiography, and Doppler flow parameters.


RESULTS
Fetuses with HLHS demonstrated reduced peak global RV longitudinal velocity (P < .01), strain (P < .001), and displacement (P < .05), while radial displacement was increased (P < .001) compared with the normal fetal right ventricle. Mean RV diameter was increased in HLHS (P < .001), but length was unchanged. The ratio of longitudinal to circumferential deformation was reduced in HLHS compared with the normal right ventricle (P < .001) and equivalent to the normal left ventricle. Tricuspid inflow peak A-wave velocity (P < .01), A-wave duration, A-wave inflow fraction, RV Tei index (P < .05 for all), and inferior vena cava A-wave reversal (P < .0001) were increased in HLHS.


CONCLUSIONS
The fetal right ventricle in HLHS becomes more spherical because of increased RV diameter. It has relatively reduced longitudinal compared with circumferential deformation and an increased reliance on atrial contraction for ventricular filling. These findings are similar to postnatal changes observed in the systemic right ventricle in palliated congenital heart disease, suggesting that ventricular remodeling is initiated in fetal life.
Fetal and Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Women and Children's Health Research and Mazankowski Alberta Heart Institutes, University of Alberta, Edmonton, AB, Canada.
Paul A
PA
Brooks
Nee S
NS
Khoo
Andrew S
AS
Mackie
Lisa K
LK
Hornberger
D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000150:complications* / Q000000981:diagnostic imaging*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging* / Q000209:etiology*