PI time constraints

The investigators are beginning a clinical research study here at UCSF to learn more about how hearts with single ventricles work. The investigators hypothesize that myocardial strain , as measured by cardiac MRI,in patients with single ventricles differs from normal hearts. This abnormality is associated with depressed cardiac power output and impaired exercise capacity. The study will utilize cardiac magnetic resonance imaging, exercise testing, and lung function testing to study how the single ventricle heart works so that in the future the investigators can improve how the investigators care for patients with this type of congenital heart disease.

The research protocol involves: Cardiac magnetic resonance imaging (MRI of the heart), exercise tests, and lung function tests. Some of these tests are routinely used to follow patients with single ventricles. Some of these tests are part of the research protocol. If you agree to participate in this study, these tests will be performed at UCSF. The results of the routine tests will be shared with your doctor.

Participation will require approximately 30 additional minutes to the cardiac MRI procedure to collect the research data. The exercise tests, and lung function tests time commitment will take about two hours.

Inclusion Criteria:

• Anatomy: The investigators will enroll 10 patients with single right ventricles status post Fontan and 10 patients with single left ventricles status post Fontan.
• Age range: 5 patients in each group will be between the ages of 10-18 years of age and 5 patients in each group will be older than 18 years of age.

Exclusion Criteria:

• Study subjects will be excluded if there are any contraindications to MRI including permanent pacemaker, ICD, retained permanent wires, cerebral aneurysm clips, neurostimulators, insulin or infusion pumps, implanted drug infusion devices, bone growth/fusion stimulators, or cochlear implants.
• In addition, patients with implanted hardware that may lead to inadequate imaging, such as steel coils or ventricular septal defect occluder devices, will be excluded.
• Finally, patients with developmental delay or physical limitations precluding cooperation with the MRI or exercise test or patients with claustrophobia will be excluded. Patients will be asked if there is any chance that they are pregnant. If they are possibly pregnant, they will be excluded.

Study subjects: Patients with univentricular hearts who have undergone a Fontan procedure will be recruited for participation in the study.