Identification of patients at risk of stroke from atrial fibrillation

Atrial fibrillation (AF) is a highly prevalent arrhythmia associated with a fivefold increase in the risk of stroke. However, this risk is not homogeneous and varies considerably depending on the presence of several demographic and clinical factors. Independent risk factors for stroke in patients with AF include age ≥65 years, female sex, congestive heart failure, prior stroke or transient ischemic attack, hypertension, diabetes mellitus and vascular disease. Based on these indicators, risk stratification schemes to identify patients at low-, moderate-, and high-risk for stroke have been developed and validated. The CHADS₂ and CHA₂DS₂-VASc schemes are widely used and have good predictive accuracy for stroke. Current guidelines recommend the CHA₂DS₂-VASc scheme, in part because it more accurately identifies patients at truly low risk for stroke who do not require antithrombotic therapy. This article provides an overview of risk factors for stroke in patients with AF, including discussion of the CHADS₂ and CHA₂DS₂-VASc schemes.