Factors associated with exercise capacity in patients with a systemic right ventricle

Systemic right ventricle (RV) is a rare and complex congenital heart disease (CHD). Patients with a systemic RV present with a significant decrease of their exercise capacity. We aimed at identifying clinical and paraclinical factors associated with maximum oxygen uptake (VO2_max) in adults with a systemic RV.

This multicentre cross-sectional study was performed 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 VO2_max, as measured by cardiopulmonary exercise test (CPET).

A total of 111 patients were included in the study (85% d-TGA, median age 37.2 ± 8.2 years). Most patients presented with impaired physical capacity (mean VO2_max of 23.3 ± 6.9 ml/kg/min, representing 68.4 ± 16.6% of predicted values) and ventilatory anaerobic threshold (VAT) impaired (mean 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 systemic RV, decreased RV function values in cardiac imaging, 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 associated with the NYHA functional class. The final multivariate model explained 49% of the variability of VO2_max.

NYHA functional class and RV function are predictors of impaired exercise capacity in adult patients with systemic RV.