Evidence that pre- or perioperative statin treatment may reduce the occurrence of post-operative atrial fibrillation and improve clinical outcome in patients undergoing coronary artery bypass graft (CABG) or major vascular surgery has been largely generated by observational studies. In a recent meta-analysis of 6 randomized trials (of which only 2 had postoperative atrial fibrillation (AF) as a predefined outcome) evaluating the use of perioperative statin treatment in patients undergoing cardiac surgery (n=651 patients in total - study size between 40 and 200 patients), statin use was found to reduce the patients' relative risk of developing postoperative AF by 43% (RR 0.57, 95%CI 0.45,0.72) and their absolute risk by 14% (95% CI 8%,20%). Although these findings would be consistent with a rapid and, possibly, lipid-independent antiarrhythmic effect of statins, they have important limitations (e.g., single-centre, small size, lack of continuous ECG monitoring, mostly "ancillary" findings") and less bearing on current clinical practice, as they mostly included statin-naïve patients. For these reasons, the recent guidelines for the management of AF have not given a strong recommendation for the use of statins in the prevention of postoperative AF. Thus, whether intensive statin treatment in the perioperative period is associated with prevention of AF, cardio protection, and improved clinical outcome remains to be demonstrated.