The association between atrial fibrillation (AF) and stroke has been well described, dating back to early observational data from the Framingham Heart Study.1 In that cohort, there was a 5-fold increased risk of stroke among patients with AF. These data, in part, led to the development of robust clinical evidence that supported the net clinical benefit of oral anticoagulation (OAC) therapy to reduce the risk of stroke in patients with AF.2