National Heart Research Institute Singapore, National Heart Centre Singapore (S.L., X.D.Z., W.R., A.S.K., R.-S.T., J.L.T., L.Z.).Department of Cardiology, West China Hospital, Sichuan University, Chengdu City, Sichuan, People’s Republic of China (Y.D., Y.C.C.).WuHan Asia Heart Hospital, Wuhan City, Hubei, People’s Republic of China (Y.W., G.C.Z.).Duke-NUS Medical School, Singapore (J.C.A., A.S.K., R.-S.T., J.L.T., L.Z.).Department of Cardiology, National University Heart Centre, National University Health System, Singapore (J.W.Y.).Yong Loo Lin School of Medicine, National University of Singapore (J.W.Y.).
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Background:The transition of right ventricle (RV) from a compensated to decompensated state contributes to survival in pulmonary arterial hypertension (PAH). This study investigates the significance of right atrial (RA) dysfunction on disease progression in PAH.Methods:Eighty patients with PAH, including 58 with hemodynamically compensated RV function (PAH-C) and 22 with decompensated RV function (PAH-D), were compared with 80 age-matched and sex-matched normal controls. RA longitudinal strain and strain rate (SR) parameters corresponding to reservoir (total strain εs and strain rate SRs), conduit (passive strain εe and strain rate SRe), and booster pump (active strain εa and strain rate SRa) phases were derived by a rapid semiautomated method on cine cardiovascular magnetic resonance.Results:In PAH compared with controls, significantly reduced RA strains and SRs were observed. Among patients with PAH, PAH-D had significantly impaired RA strains and SRs compared with PAH-C. RA total strain and passive strain were the best parameters for differentiating PAH-D from PAH-C. Lower RA strain correlated with increased RA pressure (r=−0.57; P<0.0001), RV volume (r=−0.37; P=0.002) and biomarker (r=−0.53; P<0.0001), impaired RV function (r=0.46–0.72; P<0.0001), and lower exercise capacity (r=0.41; P<0.0001). Reduced RA strains were significantly associated with higher risk of clinical worsening in PAH. RA passive strain was the best predictor of a composite adverse event end point (Harrell’s C statistic,0.75; hazard ratio,0.84; P=0.019) compared with other conventional RA and RV functional measurements.Conclusions:RA phasic functions are impaired in PAH. Among patients with PAH, impaired RA strains reflect RV decompensation and higher risks and predict adverse clinical outcomes.Clinical Trial Registrationhttps://www.clinicaltrials.gov. Unique identifier: NCT02790918.