Multimodality Biomarkers for Noninvasive Assessment of the Fontan Patient

This is a single center prospective longitudinal exercise training study and will enroll approximately 50 Fontan patients and 20 controls of a similar age, gender, BMI and physical activity level between the ages of 10-40 years. Participants will undergo an MRI of the Fontan circulation. This will include imaging of the heart, lung and liver. This will include specific imaging for tissue characterization and assessment of myocardial fibrosis, liver fibrosis and disproportionate pulmonary blood flow. The investigators will then draw blood (approximately 10 ml) for assessment of serum biomarkers and circulating microRNAs of interest. The participants will undergo exercise testing and will then start a 3-6 month long cardiac rehabilitation program. After the 3-6 month study period the participants will return back for a follow up and repeat all the testing completed at enrollement.