Abstract: There is no consensus on the definition of “valvular disease” atrial fibrillation and “non valvular disease” atrial fibrillation and there are also different explanations in these concepts provided by different guidebooks. The definitions of “valvular disease” and “non valvular disease” from clinical trials are not ideal. In fact, the two types of atrial fibrillations are very different in their risk of thromboembolism and so are their anticoagulant treatment strategies. This article will review the definition of valvular atrial fibrillation and its progress in anticoagulation therapy.