The Secondary Prevention of Stroke in Patients With Atrial Fibrillation

Ischemic stroke in patients with nonrheumatic atrial fibrillation (AF) is common. No one knows how optimally to prevent its recurrence. About 15% of all ischemic strokes occur in patients with AF. 13 Conversely, about 35% of patients with AF will experience ischemic stroke during their lifetime. 4-6 In patients with AF who have experienced an initial stroke, 20% or more will experience recurrent brain infarction within one year (Table 1). Hence, the dilemma of secondary-stroke prevention in patients with AF is a common one. Not all ischemic strokes in patients with AF are caused by cardiogenic embolism, since cerebrovascular atherosclerosis often coexists in elderly patients with AF. The fraction of these strokes due to cardiogenic embolism is uncertain, as clinical and even autopsy data are discrepant (Table 2). All causes of nonrheumatic AF seem to share a similar embolic potential, with the common denominator of stasis within the left atrium