[Use of warfarin anticoagulation in patients with atrial fibrillation in Iceland.].

Objective: Despite convincing evidence that warfarin anticoagulation reduces the risk of thromboembolism in patients with atrial fibrillation, recent data suggests that this therapy may be underutilized. Some patients are at higher risk than others and known risk factors for thromboembolism in nonvalvular atrial fibrillation include hypertension, diabetes, a prior history of a cerebrovascular accident or a transient ischemic attack and age over 65 years. Additionally, decreased left ventricular function and an enlarged left atrium increase the risk of emboli.