Silent cerebral infarction in chronic atrial fibrillation

Atrial fibrillation (AF) is associated with an increased risk of stroke. In AF patients with acute stroke, cerebral computed tomography (CT) often reveals old asymptomatic infarcts. To investigate the frequency of such lesions, 29 AF patients and 29 controls in sinus rhythm without history of cerebrovascular disease were CT scanned. Fourteen patients with AF (48%) had abnormal CT scans with areas of low density with sharp demarcation from surrounding tissue compared with 8 patients in sinus rhythm (28%) (p greater than 0.10). However, the number of abnormal areas with apparent tissue loss was significantly higher in the AF group (39 lesions) compared with the control group (16 lesions) (p = 0.033). The lesions were mainly located in the cortex with no significant difference in lesion size between AF patients and controls. The abnormal areas probably reflected small, clinically silent infarcts. We conclude that these lesions are present in AF patients without history of cerebrovascular events and occur more frequently than in controls without atrial fibrillation.