Finerenone and Atrial Fibrillation in Heart Failure

Importance: Heart failure (HF) with mildly reduced or preserved ejection fraction and atrial fibrillation (AF) are closely intertwined. Objective: To examine the efficacy and safety of the nonsteroidal mineralocorticoid receptor antagonist finerenone in patients with HF with mildly reduced or preserved ejection fraction according to the absence or presence of AF and the type of AF (paroxysmal vs persistent or permanent). Design, Setting, and Participants: Prespecified analyses were conducted in the Finerenone Trial to Investigate Efficacy and Safety Superior to Placebo in Patients With Heart Failure (FINEARTS-HF) randomized clinical trial. The trial was conducted across 653 sites in 37 countries. Participants were adults aged 40 years and older with symptomatic HF and left ventricular ejection fraction of 40% or greater, randomized between September 2020 and January 2023. Data analysis was conducted from September 1 to October 1, 2024. Intervention: Finerenone (titrated to 20 mg or 40 mg) or placebo. Main Outcomes and Measures: The primary outcome was the composite of total HF events and cardiovascular death. New-onset AF or atrial flutter (AFL) was a prespecified exploratory outcome. Results: Among 5984 patients (mean [SD] age, 72.0 [9.6] years; 2724 [45.5%] female) with known AF status at baseline, 1384 (23.1%) had paroxysmal AF and 1886 (31.5%) had persistent or permanent AF. Patients with both types of AF were older and had worse HF status compared with those without AF (2714 patients [45.4%]). Both types of AF were associated with a higher unadjusted risk of the primary outcome compared with no AF (event rate per 100 person-years of follow-up, 20.3 [95% CI, 17.9-23.1] with paroxysmal AF, 19.8 [95% CI, 17.8-22.0] with persistent or permanent AF, and 11.9 [95% CI, 10.7-13.3] with no AF; rate ratio [RR], 1.62 [95% CI, 1.37-1.92] with paroxysmal AF and 1.66 [95% CI, 1.43-1.93] with persistent or permanent AF vs no AF); however, the associations were attenuated after adjustment for known prognostic variables. The benefit of finerenone on the primary outcome (overall RR, 0.84 [95% CI, 0.74-0.95]) was not modified by baseline AF status (RR, 0.80 [95% CI, 0.65-0.98] with no AF, 0.83 [95% CI, 0.65-1.06] with paroxysmal AF, and 0.85 [95% CI, 0.69-1.05] with persistent or permanent AF; P for interaction = .94). New-onset AF or AFL occurred in 6.5% of patients and was associated with a higher subsequent adjusted risk of the primary outcome (rate ratio, 3.65 [95% CI, 2.57-5.18]; P < .001). The subdistribution hazard ratio for new-onset AF or AFL among those receiving finerenone vs placebo was 0.77 (95% CI, 0.57-1.04; P = .09). Conclusions and Relevance: The efficacy of finerenone was consistent regardless of AF status. New-onset AF was associated with a substantially higher risk of subsequent outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT04435626.