Prevention of embolic complications in nonvalvular atrial fibrillation in the elderly.

Atrial fibrillation is common in elderly subjects, usually with coexistent underlying heart disease. Nonvalvular atrial fibrillation is associated with increased morbidity and mortality, especially due to embolic complications: it carries a 5.6-fold increased risk of stroke, compared with age-matched controls. Three recent trials have demonstrated that prophylactic anticoagulation (either 'full' or 'partial') decreases the rate of stroke significantly, with an acceptably low rate of complications. The benefits of aspirin prophylaxis are less clear, and currently there is no evidence for a beneficial effect in the elderly patient. At present, no factor apart from a previous symptomatic embolism predicts those who are at risk of embolism. The risk of stroke appears to continue for a long time and, until data are provided, therapy should be continued indefinitely in the absence of contraindications. All patients with nonvalvular atrial fibrillation should be considered for prophylactic anticoagulants. Further work is required to identify those at highest risk, and to clarify how long therapy should be continued and whether there are subgroups in whom full or partial anticoagulation would be preferable.