(a) Ventricular EDV z-scores, and (b) Ventricular mass z-scores decreased in the low-risk (black, n=116) but not in the high-risk (red, n=38) genotype groups from pre-SCPC to final study visit. High-risk, ≥ 2 homozygous risk genotypes; Low-risk, < 2 homozygous risk genotypes. *p<0.05 from pre-SCPC; # p<0.05 from low-risk group at 14 months. SCPC = superior cavopulmonary connection; EDV = end-diastolic volume