The goals of this study are to quantify right ventricular-pulmonary vascular interactions in different types of PAH, to determine the temporal changes in these interactions with PAH progression and to quantify the effects of exercise on right ventricular function. The inclusion of the subpopulation of PAH patients with systemic sclerosis (SSc) was a result of the anticipation that this group has worse arterial stiffening than other groups, and consequently more inefficient right ventricular-pulmonary vascular interactions, which account for their worse prognosis.
