“Whether or not atrial fibrillation (AF) is an independent predictor of outcome in heart failure (HF),” comment the EMPHASIS-HF investigators, “its occurrence is commonly associated with symptom deterioration ... Consequently, AF is best avoided, if possible.” A prospective analysis of EMPHASIS-HF has demonstrated that the mineralocorticoid-receptor antagonist eplerenone is associated with reduced incidence of new-onset AF in the setting of mild systolic HF.

The EMPHASIS-HF investigators assessed patients with mild systolic HF both with (n = 943) and without (n = 1,794) AF or atrial flutter (AFF) at baseline. In the patients without AFF, eplerenone was associated with a reduced rate of new-onset AF during follow-up (median 21 months; 2.7% vs 4.5%; HR 0.58, 95% CI 0.35–0.96, P = 0.034). A trend remained when the data was adjusted for covariates (HR 0.71, 95% CI 0.49–1.05, P = 0.087).

The effect of eplerenone on first occurrence of cardiovascular death or hospitalization for HF (the primary end point of EMPHASIS-HF) did not differ between patients with (HR 0.60, 95% CI 0.46–0.79) and without (HR 0.70, 95% CI 0.57–0.85) AFF at baseline (P for interaction = 0.411).

Few treatments are proven to prevent new-onset AF in patients with HF. Therefore, the news that eplerenone (added to recommended therapy) was associated with reduced incidence of new-onset AF in the patients assessed in EMPHASIS-HF is a welcome addition to the literature.