ANTICOAGULATION IN ATRIAL-FIBRILLATION - FOR AND AGAINST

Atrial fibrillation is a common arrhythmia, and the risk of embolic stroke in patients with nonrheumatic atrial fibrillation is increased about fivefold. Until recently, there has been no consensus on the use of anticoagulants in patients with nonrheumatic atrial fibrillation, and the role of aspirin has been controversial. Since 1989, 5 randomized, controlled trials have been published comparing warfarin or aspirin with placebo for primary prevention of stroke in patients with nonrheumatic atrial fibrillation. All these trials have shown a clear benefit of anticoagulant therapy (risk reduction 35 to 86%), whereas the benefit of aspirin has been less obvious (risk reduction 15 to 42%). In all these studies, anticoagulation level was moderate (INR 1.5 to 3.0), and the rate of major bleeding was reported to be low (0.8 to 2.5% per year). Anticoagulant therapy does not seem to be warranted in patients <60 years old with lone atrial fibrillation, and the decision should be individualized in patients >75 years old in whom the risk of major bleeding is high. In these situations, aspirin (325 mg per day) appears to be a safe and reasonable native.