Physical Activity Promotion in Children and Adolescents With Single Ventricle Physiology (MedBike)

Children with single ventricular (SV) heart were a uniformly fatal condition prior to descriptions of surgical palliation in 1980 that results in a Fontan circulation with single ventricle physiology. In the present era, 5-year survival is 75% in multicenter studies, with some centers including the Stollery Children's Hospital reporting higher survival. Although mortality remains a challenge for this population, the research focus has shifted towards optimizing management of late complications as well as improving patient physical and mental health-related quality of life issues. Children with SV have decreased exercise tolerance and the reduction is progressive through adolescence and into adulthood. Physical factors contributing to decreased exercise tolerance in the Fontan patient include cardiovascular inefficiencies and the loss of peripheral lean muscle mass and efficiency from deconditioning. Recently, Cordina et al. has shown that an intensive exercise regiment can improve muscle strength and mass, cardiac output and exercise capacity in adults with Fontan circulation. The majority of published outcomes from exercise training in patients with congenital heart disease (CHD) have resulted in increased measured exercise capacity with no apparent negative effect. Although the link between improved exercise capacity and improved patient quality of life remains controversial, participation in an aerobic exercise regimen leads to improved health-related quality of life.

Aside from physical limitations to their exercise capacity, Fontan patient self-confidence toward physical activity is low, as is exercise participation. Studies indicate that amongst youth with CHD, low self-confidence may be a more important predictor of participation than the severity of the disease. Parental overprotection is a common finding in children with CHD with a lasting impact on patient self-confidence and anxieties toward physical activity well into adulthood. Alteration of patient and parental perception and anxieties toward participation in physical activity may improve compliance to exercise training and encourage more positive patient perceptions toward healthy lifestyle habits, including frequent physical activity participation.

Recent technological advances in remote health assessment capabilities and telehealth systems have allowed the development of medically supervised home graduated physical training for adult cardiac patient rehabilitation. The application of such technologies to pediatric congenital heart patients has not been tested. In collaboration with Prof. Boulanger at the Advanced Man Machine Interface Laboratory at the University of Alberta, a custom pediatric remote bike ergometer (MedBike) was developed. This technology provides the medical supervisor with a live-feed of patient video/audio, electrocardiograph (ECG), blood pressure (BP) and blood oximetry signals while enabling remote determination of patient work load through the bike ergometer. The long-term goal is to use this technology to improve patient exercise capacity and to positively influence patient and parental perceptions of the patient's physical ability.

Stage 2 (HIIT exercise program): The investigators will evaluate the safety and efficacy of an 8-week, 3 times per week supervised HIIT exercise program in patients with SV physiology.

All eligible patients will undergo a full cardio pulmonary exercise testing (CPET) and anthropometry assessment of lean muscle mass prior to exercise training and at the end of the training period. Understanding that a patient's CPET results may change over time, subjects who participated in Stage 1 of the study will be invited back to undergo a new baseline CPET to ensure the reliability of the data.