Right Ventricular Stiffness Impairs Right Atrial Function In Pulmonary Arterial Hypertension

Background: In pulmonary arterial hypertension (PAH) patients, right ventricular (RV) stiffness is associated with disease severity and mortality. However, the interplay between RV stiffness, ventricular filling and right atrial (RA) function remains elusive. Aim: To investigate whether RV stiffness influences RA function and RV filling in PAH patients. Methods: We determined end-diastolic elastance (stiffness, Eed) in 31 controls and 97 PAH patients. RA strain and RV volumes were measured with magnetic resonance imaging. Results: Median Eed was higher in patients than controls (0.635 [0.40-0.99] vs. 0.20 [0.15-0.24] mmHg/ml; p In patients with a stiff RV (Eed \u003e median), RA conduit strain was worse than in patients with a compliant RV (figure). However, no correlation between RA active strain and Eed was observed (Spearman rho 0.06; p=0.57). Conclusions: RV stiffness in PAH patients is accompanied by decreased RA conduit strain, but did not correlate with RA active strain. Passive RV filling in patients is impaired, but active filling is preserved.