Purpose Acceleration of the myocardium during isovolumic contraction (IVA) and right ventricular myocardial performance index (RVMPI) have been previously described as indices of right ventricular (RV) contractility. However they have not been validated in a model of chronic pressure overload. Methods and Materials Chronic pulmonary hypertension (PH) was induced in pigs by ligation of the left pulmonary artery (PA) followed by weekly embolizations of the right lower lobe for 5 weeks (PH group, n=11). Sham-operated animals were used as controls (n=5). RV remodeling was assessed using echocardiography, conductance catheterism and stroke volume (SV) reserve following dobutamine infusion (5 mcg/kg/min). Right ventricular fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), RVMPI and IVA were used for RV systolic function assessment. Results At 5 weeks, mean PA pressure (35±9 vs. 13±2 mm Hg, P P =0.01) were increased in PH animals compared to controls. Although RV elastance increased at 5 weeks in the PH group (0.55±0.14 vs. 0.34±0.06 mm Hg/ml, P =0.007), RV-PA coupling measured by the ratio of RV to PA elastance was decreased at 5 weeks (0.68±0.17 vs. 1.18±0.18, P P P =0.017; R²=0.59, P =0.003; R²=0.83, P P 2 =0.83, P Conclusions IVA as well as RVMPI, RVFAC and TAPSE are markers of RV-PA coupling rather than RV contractility in a model of chronic PH.