Systemic right ventricle (SRV) is a rare and complex congenital heart disease (CHD). Patients with a SVR present with a significant decrease of their exercise capacity. We aimed atidentifying clinical and paraclinicalfactors associated with maximum oxygen uptake (VO2_max) in adults with SRV.

This multicentre cross-sectional study was performed from in 2017 in three French tertiary care CHD centres. Adult patients with a D-transposition of the great artery (d-TGA) or a congenitally corrected TGA (cc-TGA) were included. Demographic, clinical, laboratory and imaging data were collected. Univariate and multivariate analyses were performed to identify predictors of impaired VO2max, as measured by cardiopulmonary exercise test (CPET).

A total of 111patients were included in the study (85% d-TGA, median age 37.2±8.2years). Most patients presented with impaired physical capacity (mean VO2_maxof 23.3±6.9ml/kg/min, representing 68.4±16.6% of predicted values) and muscular deconditioning (mean ventilatory anaerobic threshold (VAT) of 32.7%±10.9% of the predicted values). In univariate analysis, VO2_max correlated with professional status, NYHA functional class, BNP level, the type of SRV, SRV systolic dysfunction, the severity of tricuspid regurgitation, the presence of a pacemaker or an implantable defibrillator, the VAT, the maximum load, and the maximal heart rate during exercise. In multivariate analysis, the VO2_max remained affected by the NYHA functional class. The final multivariate model explained 49% of the variability of VO2_max.

NYHA functional class is the strongest predictor of impaired exercise capacity in adult patients with SRV.