Peak Oxygen Consumption (V̇O2peak) Recovery Delay in a Pediatric Fontan Population

Abstract

ABSTRACT Patients with single ventricle heart disease after Fontan palliation are subject to progressive cardiovascular deterioration during adolescence. In this population, a peak oxygen consumption (V̇O2peak) less than 50% of predicted is an independent predictor of Fontan-related morbidity and mortality. A greater delay in postexercise V̇O2 recovery (VO2RD) is associated with worse outcomes in adults with heart failure, however, VO2RD has not been extensively studied in youth with Fontan (single ventricle) physiology. Purpose The purpose of this study is to identify predictors and correlates of VO2RD in youth with Fontan. Methods Cardiopulmonary exercise test data was used from a single center, cross-sectional study of children and adolescents (age, 8–21 yr) with Fontan physiology. The VO2RD was determined using time (s) to <90% of V̇O2peak and categorized as “low” (≤10 s) or “high” (≥10 s). t Tests and χ2 analysis were used to compare continuous and categorical variables, respectively. Results The analysis sample included 30 adolescents with Fontan physiology (age, 14.2 ± 2.4 yr; 67% male) with either right ventricular (RV) dominant (40%) or co/left ventricular (Co/LV) dominant (60%) systemic ventricular morphology. There were no differences in V̇O2peak between the high and low VO2RD groups (high = 1.3 ± 0.4 L·min−1; low = 1.3 ± 0.3 L·min−1; P = 0.97). VO2RD in participants with RV dominance was significantly greater than in patients with Co/LV dominance (RV = 23.8 ± 15.8 s; Co/LV = 11.8 ± 16.1 s; P = 0.03). Conclusions V̇O2peak was not correlated with VO2RD when analyzed as high/low VO2RD groups. However, morphology of the systemic single ventricle (RV vs Co/LV) may be related to rate of recovery in V̇O2 after a peak cardiopulmonary exercise test.