Safety and Efficacy of Apixaban in Very Old Geriatric Subjects (> 80 Years) With Atrial FIbrillation in a Prospective reAl World Study;

Inclusion Criteria: * Male or female patients aged 80 years and older. * Patients with non-valvular atrial fibrillation (documented on electrocardiography or other medical evidence like medical chart, hospital discharge note, physician's letter within 3 years before enrollment). * Followed in geriatric settings (office consultation, acute care, rehabilitation settings and nursing homes). * Newly treated (less than 6 months) with Apixaban (5mg twice daily (or 2.5 mg twice daily for patients with 2 of the following criteria : age \> 80 years, creatinine \> 133 μmol/l, weight \< 60 kg) Exclusion Criteria: * Patient refusing to participate. * Participation to a clinical trial. * Contraindication to use of Apixaban as described in the Summary of Product Characteristics .