<p>The Fontan operation can create a stable circulation from childhood through early adulthood. However, the absence of a sub-pulmonary pumping chamber leads to a physiology in which exercise capacity is limited and decreases with age starting in adolescence. The limitation in exercise capacity is more pronounced at peak levels of exercise, but is still present during more modest levels of activity. The underlying causes of exercise impairment relate to both central cardiovascular factors (oxygen delivery) and peripheral factors (oxygen extraction). Interventions to improve cardiac preload and to improve lean muscle mass may help to improve exercise capacity and, perhaps, will alter the "natural history" of the progressive decline.</p>

<p>Children with advanced heart failure may require ventricular assist devices (VAD) while awaiting heart transplantation. Currently, no data exist regarding the safety of exercise rehabilitation (ER) in children on VAD support. The purpose of this study was to determine the safety and feasibility of ER in children on VAD support awaiting heart transplantation. Eligible patients underwent VAD placement between 1998 and 2019; both inpatient and outpatient participants were included. After VAD implantation and when ambulatory, patients were enrolled in ER. Exercise sessions were scheduled three times a week and consisted of aerobic and musculoskeletal conditioning. A total of 29 patients (59% male, mean age 14 ± 3.2&nbsp;years) were included with a median VAD duration of 120 ± 109&nbsp;days. Cardiac diagnoses included cardiomyopathy (81%) and congenital heart disease (19%). VAD type included pulsatile (59%) and continuous-flow devices (41%). Eight hundred and sixty-four (85%) ER sessions were successfully completed and began at a mean of 49&nbsp;days (range 19-108) after VAD implant. No adverse events, including episodes of hypotension, significant complex arrhythmia, or VAD malfunction occurred during exercise testing or ER, and no sessions were discontinued prematurely. Pediatric patients on VAD support can safely participate in ER with relatively high compliance, and sessions can be implemented early after VAD implantation. Given the safety profile, ER in pediatric VAD recipients, which is a modifiable pre-transplant risk factor that may improve functional capacity, warrants further study as a potential modality to improve post-transplant outcomes.</p>

<p>Exercise rehabilitation during pediatric ventricular assist device (VAD) support aims to improve musculoskeletal strengthening while awaiting heart transplantation (HT). This study aimed to determine whether increasing VAD pump speed during exercise testing and training improves exercise capacity. A single-center cohort study was performed comparing changes in exercise capacity on serial cardiopulmonary exercise testing (CPET) after exercise training at a fixed VAD pump speed (historical cohort from 2014 to 2017) compared with a prospective cohort (2017-2019) who underwent increasing pump speed during exercise training. All children were supported with intracorporeal continuous-flow VAD. Four subjects (13 ± 2.8 years) were included in the historical cohort, and 6 subjects (14 ± 1.7 years) were enrolled in the prospective cohort. Ninety percent had dilated cardiomyopathy, and one had single ventricle Fontan physiology. Baseline maximal oxygen consumption (VO2) was 19 ± 6.3 ml/kg/min. After exercise training with increased pump speed, there was substantial improvement in aerobic capacity (maximal VO2 increased 42% vs. decreased 3%, respectively) and working capacity (maximal work increased 49% vs. 13%, respectively) compared with fixed pump speed. There were no adverse events reported in either the fixed or increased pump speed cohorts. Increasing VAD pump speed during exercise training results in substantial improvement in both physical working and aerobic capacity compared a fixed pump speed in children on VAD support regardless of single or biventricular ventricle physiology. Further study of a larger cohort is needed to validate these findings to improve the approach to pediatric cardiac rehabilitation in this population.</p>

<p><strong>BACKGROUND: </strong>Obesity is associated with increased lifelong morbidity and reduced life span and is increasingly prevalent in the congenital heart disease population. Habitual exercise is an important aspect of a healthy lifestyle and primary prevention of obesity in the general population. The association between habitual activity and body mass index (BMI) has not been studied in children with congenital heart disease.</p>

<p><strong>METHODS: </strong>A cross-sectional analysis of two previously collected cohorts was performed, including participants 8 to 18 years old with tetralogy of Fallot, transposition of the great arteries, and single ventricle heart disease after a Fontan operation. The association between BMI and duration of habitual exercise (measured by questionnaire) was studied. Secondary analyses assessing the effect of other possible factors for BMI were performed.</p>

<p><strong>RESULTS: </strong>In total, 172 participants were studied (45% Tetralogy of Fallot, 12% transposition of the great arteries, and 43% Fontan). Median BMI was 18.2, and 29% of the participants were obese or overweight. Median habitual exercise was 5.9 h/wk. Thirty-eight percent of participants reported having their activity restricted by their cardiologist. Increasing exercise duration was associated with lower BMI ( P = .01) in univariate analysis. In secondary analyses, restriction to mild exertion and participation in low-intensity exercise were both associated with increased BMI.</p>

<p><strong>CONCLUSION: </strong>Increased habitual activity was associated with lower BMI, emphasizing the potential role of recreational sport in the health of children with congenital heart disease.</p>