Non-rheumatic atrial fibrillation: warfarin or aspirin for all?

Stroke is the third most common cause of death in the United Kingdom after ischaemic heart disease and cancer. Disabled patients who survive an acute stroke place a great social and economic burden on the community-stroke prevention is therefore a priority. Cerebral infarction accounts for almost 80% of all first strokes. A significant proportion of these are embolic in origin and associated with atrial fibrillation. Anticoagulant and antiplatelet drugs may reduce the risk of stroke in such patients by preventing the formation of throm-bus in the heart. What is the evidence that such treatment used as a primary preventive measure reduces the incidence of stroke in patients with atrial fibrillation? Which subgroups of patients are at high and low risk of stroke, who should be treated, and with what? Conventional indications for anticoagulant treatment in atrial fibrillation There is general agreement that patients with rheumatic or thyrotoxic atrial fibrillation and patients undergoing direct current cardiover-sion for fibrillation are at high risk of embolic stroke and that this risk is reduced by primary prevention with warfarin,'` although no adequate prospective randomised clinical trials have examined this in detail. Patients with a recent ischaemic stroke and atrial fibrillation may benefit from anticoagulation as a secondary preventive measure78; this issue is currently being prospectively investigated in the European Atrial Fibrillation Trial which may provide a clear answer when it reports in the near future.