Aly S; Lizano Santamaria RW; Devlin PJ; Jegatheeswaran A; Russell J;Seed M; McCrindle BW;

The Canadian journal of cardiology [Can J Cardiol] 2020 Jun 29. Date of Electronic Publication: 2020 Jun 29.

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) and cardiopulmonary exercise testing from 2007-2018 were reviewed. Complex rTOF patients were excluded. Obese patients (body mass index [BMI]≥95th%ile) were compared to normal-weight patients (BMI<85 ^th %ile). CMR data was indexed to actual body surface area (aBSA), height, and BSA assuming ideal body weight (iBSA).
Results: We compared 32 obese patients matched to 64 normal-weight patients. Obese versus normal-weight patients had significantly lower right (RV) and left ventricular (LV) (EF)ejection fractions (EF) [RVEF 45%(42-48) vs 52%(47-55), p<0.0001; and LVEF 52%(47-56) vs 56% (54-60), p<0.0001, respectively]. There were no statistically significant differences regarding aBSA-indexed volumes of the RV or LV at either end-diastole (EDV) or end-systole. 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 EF and impaired exercise performance after rTOF. These data suggest a potential role for cardiac rehabilitation for weight management and to optimize fitness.