Methods
This study included 52 connective tissue disease patients who had mild symptoms in World Health Organization functional classification 2, suspected as having early PAH, and underwent exercise echocardiography and right heart catheterization. Echocardiography was performed before and after the Master's two-step exercise test; the study patients were classified into the non-PAH (mean pulmonary arterial pressure < 25 mmHg, n = 37) or PAH (mean pulmonary arterial pressure ≥ 25 mmHg,n = 15) groups.