Re-Energize Fontan

RE-ENERGIZE FONTAN: A RandomizEd Exercise INtERvention DesiGned to MaximIZE Fitness in Pediatric FONTAN Patients

Survival of children with single ventricles ("half a heart") beyond the neonatal period has increased dramatically with the staged Fontan palliation. Yet, long-term morbidity remains high. By the age of 40, 50% of Fontan patients will have died or undergone heart transplantation. With >1,000 Fontan palliations performed in the US annually, there is a burgeoning population of Fontan patients at risk for progressive heart failure and death. Factors that contribute to onset and progression of heart failure in Fontan patients remain incompletely understood. However, it is established that Fontan patients have poor exercise capacity, associated with a greater risk of morbidity and mortality, in addition to decreased muscle mass, abnormal muscle function, and endothelial dysfunction contributing to disease progression. In adult patients with two ventricles and heart failure, reduced exercise capacity, muscle mass, and muscle strength are powerful predictors of poor outcomes, and exercise interventions can not only improve exercise capacity and muscle mass, but also reverse endothelial dysfunction. Limited exercise interventions in children with congenital heart disease have demonstrated that exercise is safe and effective; however, these studies have been conducted in small, heterogeneous groups, and most had few Fontan patients. Furthermore, none of these interventions have studied the impact of exercise on muscle mass or mitochondrial function, or endothelial function. The investigators propose a milestone-driven, randomized controlled trial in pediatric Fontan patients to test the hypothesis that a live-video-supervised exercise (aerobic + resistance) intervention will improve cardiac and physical capacity; muscle mass, strength and function; and endothelial function. The investigators' ultimate goal is the translation of this model to clinical application as an "exercise prescription" to intervene early in pediatric Fontan patients and decrease long-term morbidity and mortality.

Patients randomized to exercise intervention at baseline will participate in live-video-supervised exercise sessions x3/week for 3 months, and then will follow a maintenance regimen for 6 months. During maintenance, patients will continue live-video-supervised exercise sessions, only x1/week, and will be instructed to exercise on their own x2/week following an individualized prescribed exercise program and use their heart rate monitor as an activity tracker.

Patients randomized to usual care at baseline will receive usual care for 9 months and will then start the 3-month exercise intervention of live-video-supervised exercise sessions x3/week for 3 months.

The live-video-supervised exercise intervention includes exercise sessions x3/week for 3 months, and then maintenance regimen for 6 months. Maintenance includes live-video-supervised exercise sessions, only x1/week, and self-exercise x2/week following an individualized prescribed exercise program and use their heart rate monitor as an activity tracker.

Patients randomized to usual care at baseline will receive usual care for 9 months and will then start the live-video-supervised exercise intervention that includes exercise sessions x3/week for 3 months.

In Fontan patients, VO2 max is a powerful predictor of poor outcomes. The subjects will undergo progressive cardiopulmonary exercise testing with continuous monitoring by 12-lead EKG and gas exchange by measuring breath-to-breath ventilation. Exercise capacity will be measured by a cardiopulmonary exercise test to obtain the maximal oxygen uptake (VO2 max).

Inclusion Criteria: 8-19 years of age Fontan palliation Ability to fast overnight Cardiac clearance to exercise by primary cardiologist Presence of an adult at home during exercise sessions for patients <14 years old English-speaking patient. Exclusion Criteria: NYHA Class IV (severe heart failure) Acute illness within the past three months Active protein losing enteropathy (albumin <2.5 mg/dL) Implanted pacemaker Cognitive delay deemed severe enough to inhibit the ability to follow the exercise