Negative Impact of Obesity on Ventricular Size and Function and Exercise Performance in Children and Adolescents With Repaired Tetralogy of Fallot.

BACKGROUND: Up to 25% of children with congenital heart disease are obese, which may have negative physiologic consequences for patients with repaired tetralogy of Fallot (rTOF). METHODS: Patients with rTOF who underwent cardiac magnetic resonance (CMR) imaging and cardiopulmonary exercise testing from 2007 to 2018 were reviewed. Complex rTOF patients were excluded. Obese patients (body mass index [BMI] ≥ 95th percentile) were compared with normal-weight patients (BMI \u3c 85th percentile). CMR data were indexed to actual body surface area (aBSA), height, and BSA assuming ideal body weight (iBSA). RESULTS: We compared 32 obese patients matched with 64 normal-weight patients. Obese vs normal-weight patients had significantly lower right (RV; median 45% [interquartile range 42%-48%] vs 52% [47%-55%]; P \u3c 0.0001) and left (LV; 52% [47%-56%] vs 56% [54%-60%]; P \u3c 0.0001) ventricular ejection fractions (EFs). There were no statistically significant differences regarding aBSA-indexed volumes of the RV or LV at either end-diastole (EDV) or end-systole (ESV). However, when indexed to either height or iBSA, obese patients had significantly greater RVEDV and LVEDV, greater LV mass, and higher RV and LV stroke volumes. Obese patients had lower peak oxygen consumption and oxygen consumption at anaerobic threshold. These results did not change after adjusting for degree of pulmonary regurgitation. CONCLUSIONS: Obesity is associated with increased biventricular size, decreased biventricular EFs, and impaired exercise performance after rTOF. These data suggest a potential role for cardiac rehabilitation for weight management and to optimize fitness