The analysis covers six randomized controlled statin trials: three in patients who had a history of paroxysmal AF, or who underwent cardioversion due to persistent AF; two in patients undergoing cardiac surgery; and one in patients with acute coronary syndromes (ACS).

The trials included 3557 patients, 386 of whom developed recurrent or new-onset AF.

Laurent Fauchier (Centre Hospitalier Universitaire Trousseau, Tours, France) and team found that, overall, patients who received a statin had a significant 61% reduction in the relative risk for AF compared with those given placebo.

The benefits of statin therapy seemed most evident among patients with previous AF, who had a 67% reduction in the risk for a recurrence. This subgroup result was nonsignificant, however, with a confidence interval of 0.10-1.03.

Statin therapy resulted in a nonsignificant 40% reduction in the risk for new-onset AF after ACS or surgery, with a confidence interval of 0.27-1.37.

"The lower number of patients with new-onset or post-operative AF might in part explain the lack of significance for this subgroup," the team speculates in the Journal of the American College of Cardiology.

The researchers say that large, prospective, randomized trials are needed to confirm the protective effects of statins against AF in different patient populations.

However, they observe that such trials are unlikely to occur in patients with coronary heart disease because it would be considered unethical to randomize such patients to placebo.

"In contrast, but possibly very interestingly, it remains to be determined whether statins might bring some benefit in patients with AF without any type of established atherosclerotic disease or with a low risk of atherogenesis," write Fauchier and colleagues.