Statins have rapid and significant actions that have potentially important (but not yet proven) implications for postoperative atrial fibrillation and cardiac protection in patients undergoing cardiac surgery. The focus of this study is, therefore, on patients having surgical aortic valve replacement (with aortotomy) and the development of postoperative atrial fibrillation (POAF). Our aims are: to investigate the risk of POAF, infection or other complications after SAVR in continuous versus preoperative discontinuous treatment with statins. The study is a single centre randomized controlled trial with continuance treatment with statin vs. discontinuance (7 to 14 days prior surgery until the 30th post-operative day included), on patients undergoing elective solitary SAVR with bioprosthesis with prior usage of statins the last 3 months and of at least 7 days. This randomized studies will address 2 separate hypotheses in patients undergoing open heart operation with solitary aortic valve replacement with a bioprosthetic valve that 1. Discontinuation of HMG-CoA reductase inhibitors 7 to 14 days preoperative until 30 days postoperative of AVR in patients with prior use of HMG-CoA reductase inhibitors is not associated with increased early (\<30 days) risk of POAF. 2. Discontinuation of HMG-CoA reductase inhibitors 7 to 14 days preoperative until 30 days postoperative of AVR in patients with prior use of HMG-CoA reductase inhibitors is not associated with increased early (\<30 days) and intermediate (\<1 year) risk of mortality, MI, stroke and rehospitalisation.