Right ventricular free wall longitudinal strain ( FWLS ) and LV global circumferential strain ( CS ) were measured at baseline , 12 weeks , and 24 weeks in 68 patients with advanced PAH randomized to imatinib or placebo in the Imatinib in Pulmonary arterial hypertension , a Randomized Efficacy Study ( IMPRES ) trial , and compared with 30 healthy controls .