Impact of right ventricular work and pulmonary arterial compliance on peak exercise oxygen uptake in idiopathic pulmonary arterial hypertension

•The dynamic interplay between pulmonary vascular reserve, RV performance and pVO2 remains incompletely characterized in idiopathic PAH.•Reduced pulmonary vascular reserve and decreased exercise RV work impact pVO2 in idiopathic PAH.•The findings point to the central role of load dependent measures of RV function and pulsatile RV afterload to idiopathic PAH exercise capacity.•The findings further highlight the pivotal role of hemodynamic coupling in determining exercise capacity in idiopathic PAH patients.