Diffuse Myocardial Fibrosis in Fontan Patients

Inclusion criteria: adult patients (age ≥18) with a previous Fontan procedure (including all variants) referred for catheterization. This includes individuals with tricuspid atresia, double inlet left ventricle, unbalanced atrioventricular septal defect, and pulmonary atresia with intact septum. Control subjects will be selected from individuals referred to the lab for evaluation/closure of a patent foramen ovale (PFO). All subjects must be willing to participate in all portions of the study and provide written informed consent. Exclusion criteria: contraindications to MRI such as ferromagnetic objects in the chest, claustrophobia, or contraindication to gadolinium contrast (estimated creatinine clearance \< 30 ml/min/1.73m2). Fontan patients with a morphologic right ventricle (namely hypoplastic left heart after a Norwood palliation) will be excluded, because of the disproportionate risk of systolic dysfunction in the morphologic right ventricle.33 Control patients with hypertension, diabetes, coronary disease, or reduced systolic function will be excluded.