Abstract
Ambrisentan in 22 patients with pulmonary hypertension diagnosed during exercise (ePH) improved pulmonary hemodynamics; however, there was only a trend toward increased maximum oxygen uptake (VO(2)max) secondary to decreased maximum exercise systemic oxygen extraction (Ca-vO(2)). We speculate that improved pulmonary hemodynamics at maximum exercise "unmasked" a pre-existing skeletal muscle abnormality.