The aldosterone antagonist eplerenone manufactured by Pfizer has been shown to significantly reduce the incidence of new onset atrial fibrillation and flutter (AFF) in patients with class 2 heart failure, concludes a sub-analysis of the EMPHASIS-HF trial, presented at the Heart Failure Congress 2011, organized by the Heart Failure Association of the European Society of Cardiology (ESC). The analysis showed that the beneficial effects of eplerenone in reducing major CV events were similar in patients with and without AFF at the start of the study.

The Eplerenone in Mild Patients Hospitalization And Survival Study in Heart Failure study (EMPHASIS-HF) -- which involved 2737 patients from 278 centres with NYHA class 2 heart failure and ejection fractions of no more than 35% -- set out to address the question of whether eplerenone was effective in patients with mild heart failure. Patients were randomized to receive eplerenone (25mg once daily, up titrated to 50 mg daily if required) or placebo in addition to recommended therapy. The trial was stopped after 21 months due to the significant benefits in the eplerenone group. In the current presentation, the investigators have re-analyzed the original data to explore the development of new onset atrial fibrillation or flutter (AFF) in patients who had no history of AFF at baseline. The study also set out to determine whether eplerenone worked as well in patients who already had AFF at baseline as those who did not. Results at an average follow-up of two years showed that new onset AFF occurred in 25/911 (2.7%) of the patients in the group randomized to eplerenone versus 40/883 (4.5%) in the group randomized to placebo (hazard ratio (HR) 0.58 95% CI 0.35-0.96, p=0.034). The analysis also showed that the risk of cardiovascular (CV) death or hospital admission for worsening heart failure (the primary endpoint of the original study) was not significantly different in patients with and without AFF at baseline (P=0.33).
Commenting on the results study presenter Karl Swedberg, from the University of Gothenburg, Sweden, said, "This latest analysis makes an even stronger case for the use of eplerenone in patients with mild heart failure because in addition to reducing mortality it also reduces the incidence of AF. AF is a condition which both increases morbidity and complicates the care of patients with heart failure."