Silent brain infection in nonrheumatic atrial fibrillation

Abstract

Background: cerebral infarction associated with atrial fibrillation usually causes permanent neurologic disability, but several studies also reported patients with silent cerebral infarcts on CT. The clinical relevance of this finding is unknown, partly because of variable criteria for the diagnosis of 'silent' brain infarction. Methods: this report describes the frequency of silent brain infarcts in 985 patients with nonrheumatic atrial fibrillation, who shortly before suffered a symptomatic transient ischemic attack or nondisabling ischemic stroke, and evaluates the predictive value of silent infarcts for the future development of recurrent vascular events. Results: of 985 patients, 14% had CT evidence of brain infarcts not explainable by current or previous episodes of cerebral ischemia. In comparison with symptomatic infarcts, these silent infarcts were more often of the small deep lacunar type (odds ratio 5.1; 95% confidence interval 3.4-7.7). If silent and zone infarcts occurred, these often involved the territory of the posterior cerebral artery or the right hemisphere. The presence of a silent infarct at entry was associated with an increased risk of vascular events in general and of recurrent stroke in particular. This was due largely to the presence of multiple infarcts on CT. Conclusion: silent infarcts reflect advanced vascular disease.