Atrial fibrillation remains a common and challenging problem following cardiac surgery. The American College of Chest Physicians, through the Health and Science Policy Committee, established a panel to develop a set of clinical practice guidelines for the management or prophylaxis of atrial fibrillation or flutter in patients undergoing coronary artery bypass surgery. The panel based its guidelines on a systematic review of the literature that included a computerized search of PubMed and CENTRAL, the Cochrane Collaboration database, as well as a search of selected journals and references in key articles. Studies were eligible for review if they were controlled trials. Paired reviewers assessed the quality of each eligible study and extracted relevant data. The resulting data were assembled into evidence tables organized by key management questions. The panel derived recommendations that were based on this review of evidence and were formulated according to the ACCP protocol for grading evidence and strength of recommendations.