When performed with com- plete encirclement of the pulmonary veins, most commonly in combination with mitral valve repair or replacement but also with aortic or tricuspid valve procedures, the maze procedure affords freedom from AF with an efficacy similar to that of catheter-based approaches.1,2,12 15 Patients undergoing combined atrial maze procedure at the time of operation for MR have a greater free- dom from recurrent AF than those who did not have a maze procedure.11 In patients with recur- rent AF who are to undergo surgical correction of MR, catheter ablation is best deferred in favor of a concomitant surgical maze, thereby avoiding the potential complications of a catheter maze and a second procedure for the patient. 3. A reduction in thromboembolism has been demon- strated by LA ligation/excision, although the ben- efit is less evident in those patients who maintain Discontinuation of oral antico- agulation has also been associated with late stroke, highlighting that the LA appendage is not the exclusive source of all thrombi in patients with AF. Therefore, there are insufficient data to support rou- tine discontinuation of anticoagulation in patients with AF who are undergoing LA ligation/excision. 4. Ablation with radiofrequency/cryoenergy or atrial suture lines provides an endocardial thrombo- genic milieu, and in addition, surgical LA append- age occlusion can be incomplete.20 22 In the context of atrial arrhythmias, manipulation of the LA, and post-cardioversion/defibrillation stun- ning, atrial mechanical function can be slow to recover. The resultant stasis and thrombogenic endocardial lesions provide a nidus for thrombus development, placing this group of patients at CLINICAL STATEMENTS AND GUIDELINES risk of stroke. 