Background: Restricting certain patients with hypertrophic cardiomyopathy (HCM) from exercise likely has negative cardiovascular effects and may not reduce the risk of sudden cardiac death. Promoting exercise in children with HCM is complex and requires knowledge of the environmental factors that impact exercise capacity in children with HCM. Methods: This retrospective, cross-sectional analysis includes children with HCM who underwent exercise stress testing (EST) at a single, children's tertiary-care center between 2000 and 2023. Addresses from contemporaneous EST were accessed and geocoded to census tracts. The Child Opportunity Index (COI) was the primary exposure of interest. Granular neighborhood measures including walkability index, Rural-Urban Commuting Area Codes (RUCA), Index of Concentration at the Extremes and Uniform Crime Reporting rates were measured. The primary outcome measure was peak oxygen consumption (VO2). Linear regression and multivariable analyses were performed. Results: A total of 155 patients were identified who met inclusion criteria, 23% (n=35) of whom were female. Mean age at time of EST was 15.8 ±3.1 years. More than half of included patients were from high or very high COI (30%, n=46, and 35%, n=54, respectively). Most patients lived in urban environments (RUCA score 1 or 2, 96.7%, n=150). The mean peak VO2 was 2159 ±906 milliliters/min and adjusted peak VO2 35.5 ±9.3 mL/kg/min. A multivariate model adjusting for disease severity, age at diagnosis of HCM, race and accounting for collinearity, showed that low COI, higher levels of urbanization and lower concentration of neighborhood wealth were independently associated with lower peak VO2. Discussion: Our study identified previously unrecognized environmental determinants of exercise capacity in children with HCM, with lower COI, increased urbanization, and lower neighborhood wealth independently associating with lower exercise performance. Programs designed to increase physical activity levels and exercise performance in children with HCM should account for neighborhood and economic factors.

The authors have declared no competing interest.

J.J.E. was supported by NIH K08HL159311

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