LAUSR

Background: Right ventricular (RV) function is critically important in the management of pulmonary arterial hypertension (PAH). Studies have reported three indices of intrinsic RV function: end-systolic elastance [Ees]; Ees divided by the arterial elastance [Ees/Ea]; and β, an index of RV stiffness. However, little is known how these indices associate with the exercise tolerance/ventilatory efficiency in PAH. Aim: To examine the associations between intrinsic RV function and measurements of cardiopulmonary exercise test (CPET) in PAH patients. Methods: Study populations were PAH patients who underwent cardiac MRI, CPET and right heart catheterization, and matched control subjects. We compared Ees, Ees/Ea and β between the two groups, and then examined the associations of CPET-derived measures (%peak VO2 and VE/VCO2) with conventional hemodynamic indices, i.e. mean pulmonary arterial pressure, cardiac index, and right atrial pressure, and three indices of intrinsic RV function in PAH patients. Results: Eighteen PAH patients and 14 control subjects were enrolled. Ees/Ea was lower for PAH groups (1.0 ± 0.3 vs 2.4 ± 1.2, p Conclusions: Intrinsic systolic RV function is associated with alterations of exercise tolerance/ventilatory efficiency in PAH patients, suggesting its promising potential as a novel therapeutic target and a risk predictor.