The committee agreed that the evidence of no effect in the newer studies was important, because these studies were larger and of higher quality than the older studies included in the analysis. Although the newer studies suggested that statins did not affect the short-term risk of stroke, they did suggest a greater risk of mortality in the peri-operative period compared with placebo treatment or usual care. The committee agreed that although the additional risk of death was probably small, it was important, especially alongside the lack of convincing evidence of benefit. For these reasons, the committee decided that statins should not be given to prevent atrial fibrillation after cardiothoracic surgery. However, the committee wanted to highlight that statins have an important role in preventing cardiovascular events other than atrial fibrillation and that people already taking statins for other reasons should continue to do so. How the recommendations might affect practice The committee agreed that the recommendation would not constitute a change in practice, and that there would not be a resource impact on the NHS. Return to recommendations Managing atrial fibrillation after cardiothoracic surgery Why the committee made the recommendations The evidence on managing postoperative atrial fibrillation after cardiothoracic surgery in people without pre-existing atrial fibrillation was limited many of the studies reviewed were old and included small numbers of participants. There were few studies comparing drug classes, and the committee agreed that they could not recommend a particular class of drugs based on such limited evidence. One larger study comparing mixed rate control and rhythm control with a potassium-channel blocker (amiodarone) with or without rate control suggested little difference between the 2 groups. 