The registry will be used to evaluate, describe, and document the safety of target-specific anticoagulant agents (and other antithrombotic agents) in patients with Atrial Fibrillation (AF), the clinical outcomes associated with their use, the treatment patterns and clinical course of patients with AF, including those who undergo cardiac procedures of interest (ablation, cardioversion, catheterization and surgery, for examples), and characteristics of patients with new onset/first-detected AF. Additionally, the registry will be used to summarize patterns of switching or discontinuation of antithrombotic agents in the United States. The registry will be a nationwide collaboration of health care providers (eg, cardiologists, internists, primary care physicians, electrophysiologists, quality improvement personnel, office/practice managers, research coordinators, and pharmacists). Target enrollment will be approximately 15,000 patients. It is anticipated that enrollment will complete in approximately 3.5 years. Consecutive patients who meet the eligibility criteria will be approached and educated about the registry. Patients who express interest will provide informed consent. Patients enrolled in the registry will be followed for up to 2 years. New patients enrolled in the registry will be followed for up to 1 year. Patient follow-up by their AF care provider will continue as scheduled according to local clinical practice. Data collection will occur at 6 month intervals for approximately 1 year from the time of enrollment of the patient (baseline, 6, and 12 months). Data capture will include demographics, medical history, cardiovascular history, vital signs, echocardiographic and laboratory data, AF status and type (paroxysmal, persistent, long-standing persistent/permanent), pharmacotherapy, contraindications to oral anticoagulant therapy, and provider specialty. Clinical outcomes and safety data capture will include major adverse cardiac events (MACEs).