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; plt;0.001). Patients had reduced RA reservoir (14.3textpm5.19.1textpm4.3 plt;0.001) and conduit strain (-5.6textpm3.412.4textpm3.3 plt;0.001), while RA active strain was enhanced (-9.0textpm4.07.5textpm2.8 p=0.019). Passive RV filling was reduced (33textpm19ml vs. 48textpm19ml; plt;0.001), while active RV filling was preserved (22textpm17ml vs. 24textpm13ml; p=0.38).In patients with a stiff RV (Eed gt; 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.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 4047.This abstract was presented at the 2020 ERS International Congress, in session textquotedblleftRespiratory viruses in the "pre COVID-19" eratextquotedblright.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).