AF: Summary and Gaps AF is a prevalent, potent, and treatable risk factor for embolic stroke. Knowing which treatment offers the optimal balance of benefits and risks for a particular patient remains challeng- ing, however. Complicating the decision is that the field is rapidly changing, with ongoing changes in the epidemiology of AF-related stroke, improvements in the ability to predict risk of stroke and hemorrhage, and a growing armamentarium of effective therapies. This fluid environment has contributed to a proliferation of proposed guidelines, which can vary substantially. One clear goal is therefore to continue to collect sufficient data on risk stratification and treatment effects to strengthen the foundation for future recommendations. A key step toward this goal is head-to-head comparison of the newer anticoagu- lants with each other and with emerging alternatives such as LAA closure. Despite improving public awareness, anticoagulation for suitable AF patients remains underused, particularly among the very elderly. A potential benefit of the newer anticoagu- lants would be to improve use and compliance for appro- priate patients. Another step toward optimizing the use of anticoagulants is large-scale MRI studies of cerebral micro- bleeds to determine whether and when they should alter the decision to prescribe anticoagulants, especially in the elderly. Risk for future ICH may be particularly important in selecting one of the newer anticoagulants because the major advantage of these agents may be their reduced risk for this complication. AF: Recommendations 1. For patients with valvular AF at high risk for stroke, defined as a CHA2 -VASc score of 2 and accept- ably low risk for hemorrhagic complications, long- term oral anticoagulant therapy with warfarin at a target INR of 2.0 to 3.0 is recommended (Class I; Level of Evidence A). 2. 