Feasibility of an Individualized Exercise Training Program for Children with Hypertrophic Cardiomyopathy

Limited data exist to guide exercise participation in pediatric hypertrophic cardiomyopathy (HCM) patients. Exercise is traditionally restricted in this population, despite research in adults with HCM demonstrating exercise-associated cardiovascular and psychological benefit. This pilot study seeks to assesses the safety and feasibility of a moderate-intensity exercise program in children with HCM to guide future study design. Eight subjects ages 8-18 with HCM were recruited from the outpatient cardiology clinic at a large tertiary care referral center. All subjects were NYHA Class I (n = 4) or II (n = 4) and median septal wall thickness was 2.3 cm [IQR 1.4, 2.5]. The intervention included a 16-week exercise program, consisting of three 30-min aerobic and two strength sessions per week. A target heart rate zone was established using a baseline cardiopulmonary exercise test (CPET). A FitBit device was used to titrate activity to this zone during sessions. Self-reported adherence ranged from 1.25 to 96.25%. At baseline, cardiorespiratory fitness, assessed by CPET, and Health Related Quality of Life (HRQoL), assessed using two validated instruments, were reduced compared to peers. All subjects (n = 4) who completed the intervention improved in exercise performance and HRQoL measures. Ambulatory rhythm monitoring did not reveal any intervention-related arrhythmias, and there were no cardiac adverse events. This pilot study shows the promise of a potential benefit of an interventional exercise program in children with HCM. Future work should aim to improve retention, and more fully assess the safety and impact of exercise in pediatric HCM.