Prevalence of and risk factors for silent ischemic stroke in patients with atrial fibrillation as determined by brain magnetic resonance imaging.

Varied silent ischemic stroke (SS) prevalence occurs in patients with atrial fibrillation (AF). Stroke history is worth 2 points in the CHADS 2 scoring system. An unknown proportion of patients with AF with a CHADS 2 score of 0 or 1 have been undertreated for stroke prevention. We investigated SS risk factors using magnetic resonance imaging and estimated SS impact on clinical outcomes in patients with AF. We analyzed a total of 1,200 patients (400 with AF and 800 with sinus rhythm) who had brain magnetic resonance imaging performed for routine health checkups. Clinical outcomes including symptomatic stroke, dementia, and cognitive disorder were also evaluated in patients with AF (follow-up duration: 66.7 ± 35.9 months; range 10 to 162). SS was observed in 113 patients with AF (28.3%), which was significantly higher than that in 53 subjects (6.6%) with sinus rhythm (p