Impact of Atrial Fibrillation on Long‐Term Outcomes of Aortic Stenosis

Background Atrial fibrillation (AF) is common in patients with aortic stenosis (AS), but its independent long‐term prognostic impact on outcomes remains uncertain. We examined the association between AF and mortality risk across the full spectrum of AS. Method In this retrospective cohort study, we included 1592 patients with at least mild AS and preserved left ventricular ejection fraction (≥50%). Patients were stratified by AF status. Primary and secondary end points were all‐cause and cardiovascular mortality, respectively. Results Of 1592 patients, including the full spectrum of AS severity, 254 (16%) had AF. AF was more prevalent in patients with severe paradoxical low‐flow low‐gradient (36%) compared with severe normal‐flow (12%), severe high‐gradient (10%), and mild‐to‐moderate (16%) AS ( P <0.001). During a median follow‐up of 7.2 (interquartile range, 3.6–11.0) years, 885 deaths occurred (49% cardiovascular‐related). AF was associated with an increased risk of all‐cause and cardiovascular mortality (both P <0.001). In multivariable Cox models, AF independently predicted a higher risk of all‐cause (hazard ratio [HR], 1.78 [95% CI, 1.34–2.36], P <0.001) and cardiovascular (HR, 1.77 [95% CI, 1.20–2.62], P =0.004) mortality. The prognostic impact was greatest for permanent/persistent AF (HR, 2.04) and significant for paroxysmal AF (HR, 1.69). The association of AF with outcomes remained consistent across various subgroups, including AS flow‐gradient patterns (all interaction P >0.05). Conclusion In this large cohort with AS, AF was independently associated with an increased risk of both all‐cause and cardiovascular mortality, regardless of treatment strategy or AS flow‐gradient pattern. AF should be integrated into risk stratification algorithms in AS, beyond parameters of AS severity.