Statins have important pleiotropic effects and have been shown to reduce vascular inflammation and the incidence of atrial fibrillation (AF) after cardiac surgery. The role of statins in patients with existing AF is poorly understood. We examined the effect of statins on recurrence of AF in patients after successful cardioversion.

Statin use and documented recurrence of AF after successful cardioversion were evaluated in 625 patients with new onset AF who were followed prospectively in the Canadian Registry of Atrial Fibrillation. Logistic regression was used to model the effect of statin use on the recurrence of AF at 1 year while adjusting for potential confounders including concurrent medications.

In a predominantly male population (62%) with median age 63 years, 12.3% were on statins at baseline. Overall, 32.5% had documented recurrence of AF at 1 year; 23.4% in patients on statins compared to 33.8% in those not on statins (P = .07). After adjustment for baseline differences and concomitant β-blocker use, statin use was associated with a 74% reduction in AF recurrence, but only in statin users on β-blockers (OR 0.26, 95% CI 0.10-0.66); statin users not on β-blockers (OR 1.07, 95% CI 0.44-2.58).

In an observational study of patients with new onset AF, statin use was associated with a significant 74% reduction in the odds of recurrent AF, but only in patients also taking β-blockers. Importantly, statin without concomitant β-blocker use was not associated with any changes in AF recurrence.