Antithrombotic Therapy for Atrial Fibrillation CHEST Guideline and Expert Panel Report Gregory Y. H. Lip, MD; Amitava Banerjee, MD, DPhil; Giuseppe Boriani, MD, PhD; Chern en Chiang, MD, PhD; Ramiz Fargo, MD, FCCP; Ben Freedman, MD, PhD; Deirdre A. Lane, PhD; Christian T. Ruff, MD, MPH; Mintu Turakhia, MD; David Werring, PhD; Sheena Patel, MPH; and Lisa Moores, MD, FCCP BACKGROUND: The risk of stroke is heterogeneous across different groups of patients with atrial brillation (AF), being dependent on the presence of various stroke risk factors. We provide recommendations for antithrombotic treatment based on net clinical bene t for patients with AF at varying levels of stroke risk and in a number of common clinical scenarios. METHODS: Systematic literature reviews were conducted to identify relevant articles published from the last formal search perfomed for the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (9th Edition). The overall quality of the evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Graded recommendations and ungraded consensus-based statements were drafted, voted on, and revised until consensus was reached. 