However, a substantial minority of AF-related stroke occurs in patients without a prior diagnosis of the condition. Studies of active screening of patients >65 years of age for AF in primary care settings show that pulse assessment by trained personnel increases the detection of undiagnosed AF.376,377 Systematic pulse assess- ment during routine clinic visits followed by 12-lead ECG in those with an irregular pulse resulted in a 60% increase in the detection of AF.376 Risk Stratification in Patients With AF Once the diagnosis of AF is established, the next step is to estimate an individual s risks for cardioembolic stroke and for hemorrhagic complications of antithrombotic therapy. For estimating risk of AF-related cardioembolic stroke, more than a dozen risk stratification schemes have been proposed on the basis of various combinations of clinical and echocar- The widely used CHADS2 scheme (Table 3) yields a score of 0 to 6, with 1 point each given for congestive heart failure, hypertension, age 75 years, and diabetes mellitus and with 2 points given for prior stroke or transient ischemic attack (TIA).378 This scheme has been tested in multiple independent cohorts of AF patients, with 0 points corresponding to low risk (0.5% and 2 points indicating high risk (1.9%/y 7.6%/y).373 The -VASc scheme (Table 3) modifies CHADS2 by add- ing an age category (1 point for age 65 to 74 years, 2 points for age 75 years) and adding 1 point each for diagnosis of vas- cular disease (such as peripheral artery disease, MI, or aortic plaque) and for female sex. The main advantage of the more -VASc scheme for primary stroke pre- vention is improved stratification of individuals estimated to be at low to moderate risk using CHADS2 (scores of 0 to 1). 