Abstract 13884: Cardiopulmonary Exercise Testing Delineates Underlying Mechanisms of “Good” and “Poor” Exercise Performance in Post-Fontan Patients

Abstract

Background: Fontan patients have limited exercise capacity primarily due to an absence of subpulmonary ventricle by which ventricular filling is hindered in response to incremental exercise. Little is understood as to how to improve exercise performance in Fontan patients. Methods: Cardiopulmonary exercise testing (CPET) in Fontan patients were studied retrospectively. The patients were divided into “Good” and “Poor” performance by peak oxygen consumption (pVO2) at 35 and 30 ml/kg/min for males and females, respectively. Data are shown as mean ± standard deviation. Results: Table 1 presents demographic data and CPET results of males and females with “Good” and “Poor” exercise performance (total 36 patients). Ventilatory anaerobic threshold (VAT) and peak work rate (pWR) were significantly lower in male “Poor” group than in male “Good” group whereas no significant difference was noted in female groups other than pVO2. A specific trend of each group emerged when weight (kg)-pVO2 (L/min) and maximum minute ventilation (maxVE: L/min)-pVO2 (L/min) relationship were assessed, which indicated that “Good” Fontan had higher skeletal muscle mass effects in given weight and better ventilatory efficiency for oxygenation, respectively, than “Poor” group (Figure 1). Conclusions: Under the same single ventricle physiology which mitigates ventricular filling, some Fontan patients showed better exercise performance than others due to higher skeletal muscle mass effects and better ventilatory efficiency for oxygenation. A simple method of plotting of 2 CPET parameters may be useful in assessing improvement in exercise performance by muscle and breathing training in Fontan patients.