Hemorrhagic stroke was less frequent in the LAA closure group (RR, 0.09; 95% CI, 0 0.45), but ischemic stroke was insignificantly more frequent (RR, 1.34; 95% CI, 0.60 4.29), in part because of procedure-related strokes (occurring in 5 of the 449 patients in whom LAA closure was attempted, including 2 with long- term residual deficits). At 1588 patient-years of follow-up, the rate of the primary efficacy end point of stroke, systemic embolism, and cardiovascular death was not inferior for the WATCHMAN device compared with warfarin.437 Although this approach appears promising, there are substantial reasons for proceeding cautiously with this treatment, including the Meschia et al Guidelines for the Primary Prevention of Stroke 3777 relatively modest power of the trial, the exclusion of subjects with firm contraindications to anticoagulation (who would otherwise appear to be ideal candidates for LAA closure), and the lack of comparison to the newer, potentially more effec- tive oral anticoagulants. Other potential nonpharmacological approaches such as therapeutic cardioversion and rhythm con- trol do not reduce stroke risk.438 Intervals of asymptomatic AF also persist after apparently successful radiofrequency abla- suggesting a persistent need for antithrombotic treat- ment after this procedure. Several randomized, clinical trials have consistently shown that rhythm control does not protect against stroke relative to rate control.438,440 442 For patients with AF of 48 hours or when duration is unknown, it is recommended that patients receive warfarin to an INR of 2.0 to 3.0 for 3 weeks before and 4 weeks after chemical or electrical cardioversion.443 Subgroup analyses of ROCKET AF444 sug- gest that protection from cardioembolism around the time of cardioversion appears to be comparable for warfarin and the novel oral anticoagulants. AF: Summary and Gaps AF is a prevalent, potent, and treatable risk factor for embolic stroke. 