Exercise-Induced Right Atrial Stiffness Predicts Mortality Risk in Precapillary Pulmonary Hypertension

A prospective observational study involving 68 participants, including 42 with precapillary pulmonary hypertension (PH), investigated the prognostic significance of right atrial (RA) stiffness during exercise. Patients with higher exercise-induced RA stiffness demonstrated impaired cardiac output reserve and greater evidence of venous congestion despite comparable resting right ventricular function and cardiac index. Importantly, elevated exercise RA stiffness was independently associated with mortality (adjusted HR 4.37; 95% CI 1.20–15.96). A model combining RA conduit strain and right ventricular functional reserve identified patients with high RA stiffness with an AUC of 0.90. These findings suggest that exercise-based right atrial assessment may provide additional prognostic information beyond conventional resting measurements.