[Embolic complications of chronic atrial fibrillation]

Abstract

Systemic embolism secondary to chronic atrial fibrillation usually affect the cerebral circulation. The risk of a cerebrovascular accident in patients with chronic atrial fibrillation, irrespective of the aetiology, is 1.8 to 7.5 times that of the general population. The embolic risk is 18 times greater in patients with atrial fibrillation related to the rheumatic heart disease. The risk of patients under 60 years of age with idiopathic atrial fibrillation does not seem to be different to that of the general population. The risk of early recurrence of embolism in the first 30 days ranges from 8 to 15%. The risk of late recurrence varies but seems to be higher than that of the general population. The prognosis of embolic cerebrovascular accidents is poor with a 20% mortality rate. The benefits of preventive therapy of embolism with oral anticoagulants have been clearly established in rheumatic atrial fibrillation and in other indications. In non-valvular atrial fibrillation the benefits have to be compared with the risks of treatment. The incidence of hemorrhage due to anticoagulant therapy is between 3 and 5% per year per patient (about 1% of severe haemorrhage). Three randomised studies of primary prevention have shown a significant reduction of the embolic risk in non-valvular atrial fibrillation treated by warfarin compared to patients on placebo. Only one study has shown a significant reduction of the embolic risk in patients under 75 years of age with non-valvular atrial fibrillation treated with 325 mg/day of aspirin. However, anticoagulant therapy does not seem necessary in carefully selected patients under 60 years of age with idiopathic atrial fibrillation (less than 5% of all patients).