Although impaired left ventricular systolic function is a risk factor for stroke in AF, there are con icting data about whether a history of congestive heart failure per se raises the risk of ischemic stroke in AF. Although age thresholds often are used in stroke risk schemes, stroke risk in AF increases contin- uously with age, appreciably rising from age 65 years onward.20 There is moderate-quality evidence that women face a higher risk of stroke than men.18 A history of coronary artery disease has not consistently been found to be an independent risk factor for stroke in patients with AF.18 However, there is low-quality evidence that the presence of atherosclerotic vascular disease (eg, complex aor- Assessment of Stroke Risk in Patients With Nonrheumatic AF Risk Factor Points Recent Congestive heart failure exacerbation 1 History of Hypertension 1 Diabetes mellitus 1 Prior history of Stroke or transient ischemic attack 2 CHADS2 5congestive heart failure, hypertension, age 75 years, diabetes mellitus, prior stroke or transient ischemic attack. See Table 1 legend for expansion of other abbreviation. e538S Antithrombotic Therapy for Atrial Fibrillation score of 1.5, and a substantial majority (78%) of patients in the cohort had a CHADS2 score of 1.44 Although CHADS2-speci c rates of all-cause mortality are not available from this cohort, the risk of death is expected to be lower in low-risk patients with a CHADS2 score of 0 because of their younger age, lower preva- lence of vascular risk factors, and lower rates of fatal ischemic stroke. 1.6 Deriving Baseline Risk of Nonfatal Major Extracranial Bleeding To develop our recommendations, we also required estimates of the baseline risk of nonfatal major extracranial bleeding in patients with AF. 