Right atrial functional impairment is a robust prognostic marker in HFrEF mirroring pulmonary hypertension, but remains unproven in HFpEF
C Kocx, A Gao, A Paredes, A PearlmanAbstract
Background
Right atrial (RA) dysfunction is a well-established driver of mortality in pulmonary hypertension (PH), reflecting right ventricular (RV) maladaptation. However, in heart failure (HF), where RA mechanics are influenced by both RV loading and left-sided filling pressures, the prognostic utility of functional indices (strain, emptying fraction) remains less defined. We sought to determine if RA functional prognostic value in HFrEF and HFpEF parallels the robust signal seen in PH.
Methods
Consistent with our prospective registration (PROSPERO CRD420251173147), we systematically reviewed 32 cohort studies (N=3,685) evaluating echocardiographic RA functional metrics and longitudinal outcomes (primarily all-cause mortality and HF hospitalisation, or, pragmatically, composite metrics including mortality) in adults with HF or PH. Effect estimates were mapped by disease phenotype (HFrEF, HFpEF, PH) and metric type to compare prognostic consistency across conditions. Risk of bias was assessed using QUIPS.
Results
In contrast to PH studies, which predominantly relied on RA area (85% of PH cohorts), HF studies favoured RA volume index and strain. In the HFrEF cohorts (n=7), reduced RA reservoir strain and emptying fraction consistently predicted adverse outcomes independent of RV function, displaying a hazard signal magnitude (HR range 1.8–4.5) comparable to that observed in PH. Conversely, evidence in HFpEF was sparse (n=3) and heterogeneous; unlike the clear maladaptive signal in PH and HFrEF, functional RA strain in HFpEF showed inconsistent independent value after adjusting for left atrial mechanics.
Conclusion
The prognostic dominance of RA functional impairment, well-recognised in PH, extends strongly to the HFrEF phenotype. In HFrEF, RA dysfunction is a powerful, independent predictor of adverse outcomes. However, this "right-heart" risk signal is not yet confirmed in HFpEF, where left-sided interactions may obscure the relationship. Future research must validate if the RA mechanics vital in PH and HFrEF carry the same weight in the preserved ejection fraction population.