We analyzed 324 case reports of patients with different forms of atrial fibrillation: permanent, persistent and paroxysmal. We evaluated prevalence of risk factors of development of thromboembolic complications and
adequacy of use of anticoagulation of indirect effect (warfarin) in these patients. It was established that the risk of development of thromboembolic complications in patients with permanent and paroxysmal atrial fibrillation is similar. We revealed incorrect points of view of physicians about usage of warfarin in atrial fibrillation and necessity of laboratory control. At one side, warfarin wasn’t used in patients with high risk of development of thromboembolic complications, on the other side, it was used in patients with absence of obligatory indications, without proper selection of dosage and laboratory control.