[Auricular fibrillation, systemic embolism and anticoagulant treatment].

The risk of arterial embolism, specially cerebral, in patients with mitral stenosis associated atrial fibrillation is seventeen fold greater than that of the general population and five fold greater than that of non rheumatic atrial fibrillation. The usefulness of oral anticoagulant therapy in patients with atrial fibrillation and mitral stenosis is clear. In patients with non rheumatic atrial fibrillation, the controversy about its usefulness has been cleared with five recent reports showing a significant benefit or oral anticoagulation. We believe that these results may be applied to the routine management of these patients provided an adequate patient selection, consideration of contraindications and the use of a low anticoagulation range. Aspirin effectiveness in these patients is unsettled. One study showed benefits of 375 mg/day in patients younger than 75 years. The embolic risk in patients with atrial fibrillation must be stratified. High risk patients require the use of oral anticoagulation with an INR range between 3 and 4.5; those with medium risk require an INR between 2 and 3 and in some, aspirin use may be an alternative. When electrical cardioversion is indicated, oral anticoagulation must be used when atrial fibrillation has lasted for more than two days. In these cases, it is advisable to postpone cardioversion for three weeks after oral coagulation has started and to maintain this treatment for 3 or 4 additional weeks after cardioversion.