Antithrombotic treatment of atrial fibrillation Atrial fibrillation has become a serious health problem. According to Prof. Phillippe from France, based on a survey in five European countries, repeated hospitalizations and interventions for atrial fibrillation are the main cause of increased costs of atrial fibrillation treatment, exceeding 70% of the total hospitalization costs. In Europe, hospitalization for stroke due to atrial fibrillation accounts for 1/5 of all stroke patients, and mitral stenosis, post mitral valve replacement, and a history of previous stroke or TIA are high risk factors for stroke in atrial fibrillation. Both the Framingham Study in the United States and the Manitoba Study in Canada showed that mortality in patients with atrial fibrillation was nearly twice as high as in non-atrial fibrillation patients, and that atrial fibrillation resulted in significantly higher rates of stroke, heart failure, rehospitalization, and limitation of motion in patients. The risk of ischemic stroke is five times greater in patients with AF than in those without AF, and the incidence of stroke increases significantly with age, with the annual prevalence increasing from 1.5% in patients aged 50-59 years to 23.5% in patients aged 80-89 years (Lioyd-Jones D, et al. Circulation. 2009; 119: 480-6). Stroke is not reduced by ventricular rate control in atrial fibrillation. Paulus K highlighted the ACTIVE study: although the ACTIVE W study showed that the combination of clopidogrel and aspirin was inferior to oral anticoagulants in patients at intermediate and high risk of stroke, ACTIVE A showed that in patients with atrial fibrillation with a CHADS2 score above and including 1, the combination of clopidogrel and aspirin was effective in preventing vascular events in atrial fibrillation especially the risk of stroke. In patients with atrial fibrillation who are unable to take oral warfarin, clopidogrel in combination with aspirin is a more effective treatment option than aspirin. The combination of clopidogrel and aspirin significantly reduced major vascular events by 11% (p=0.014), and the benefit lasted for more than 4 years.