The current study will determine the impact of electronic alert-based CDS on prescription of anticoagulation in high-risk AF patients in the outpatient setting who are not being prescribed anticoagulation for stroke prevention. Because this is a Quality Improvement initiative, we will not mandate a specific antithrombotic agent, regimen, or duration. We will provide options for anticoagulation to prevent stroke in AF and allow the provider to make the best choice based on their clinical judgment. If there is a contraindication to anticoagulation or if the risks outweigh the benefits of antithrombotic therapy, the provider can elect to omit anticoagulation but will need to provide the rationale for doing so. The current study will also determine the impact of electronic alert-based CDS on the frequency of stroke and systemic embolic events in high-risk AF patients in the outpatient setting who are not being prescribed anticoagulation for stroke prevention. Data acquired through this study regarding the frequency of stroke and systemic embolism will be used to calculate sample size requirements for a future clinical end-point driven randomized controlled trial of electronic alerts to prevent stroke in high-risk AF patients.