O’Byrne ML; Desai S; Lane M; McBride M; Paridon S; Goldmuntz E

Pediatric Cardiology [Pediatr Cardiol], ISSN: 1432-1971, 2017 Mar; Vol. 38 (3), pp. 472-483

Increasing habitual
exercise has been associated with improved cardiopulmonary exercise
testing (CPET) performance, specifically maximal oxygen consumption in
children with operatively corrected congenital heart disease. This has
not been studied in children following Fontan palliation, a population
in whom CPET performance is dramatically diminished. A single-center
cross-sectional study with prospective and retrospective data
collection was performed that assessed habitual exercise preceding a
clinically indicated CPET in children and adolescents with Fontan
palliation, transposition of the great arteries following arterial
switch operation (TGA), and normal cardiac anatomy without prior
operation. Data from contemporaneous clinical reports and imaging
studies were collected. The association between percent predicted
VO2max and habitual exercise duration adjusted for known covariates was
tested. A total of 175 subjects (75 post-Fontan, 20 with TGA, and 80
with normal cardiac anatomy) were enrolled. VO2max was lower in the
Fontan group than patients with normal cardiac anatomy (p < 0.0001) or TGA (p < 0.0001). In Fontan subjects, both univariate and multivariate analysis failed to demonstrate a significant association between habitual exercise and VO2max (p = 0.6), in sharp contrast to cardiac normal subjects. In multivariate analysis, increasing age was the only independent risk factor associated with decreasing VO2max in the Fontan group (p = 0.003). Habitual exercise was not associated with VO2max in subjects with a Fontan as compared to biventricular circulation. Further research is necessary to understand why their habitual exercise is ineffective and/or what aspects of the Fontan circulation disrupt this association.