Atrial fibrillation and the risk of cerebral white matter lesions

Background: Cerebral white matter lesions are often observed on MRI scans o f elderly nondemented and demented persons. Their pathogenesis is not fully understood but cerebral hypoperfusion may be involved. Atrial fibrillation is a common finding in elderly subjects and may lead to a reduced cardiac output with cerebral hypoperfusion. The authors investigated the associatio n between atrial fibrillation and the presence of white matter lesions. Met hods: From 1995 through 1996, the authors randomly sampled 1077 subjects fr om two ongoing prospective population-based studies. From each participant, an electrocardiogram (ECG) was recorded; atrial fibrillation and left vent ricular hypertrophy were diagnosed with a computer program. For one of the two groups (553 subjects), earlier ECGs were available (mean follow-up 4.7 years). All subjects underwent 1.5-T MRI scanning; white matter lesions wer e separately rated for the periventricular and subcortical regions. Results : The prevalence of atrial fibrillation was 1.9% among subjects younger tha n 75 years and 5.5% in subjects older than 75 years. The total number of su bjects with atrial fibrillation was 28. Subjects with atrial fibrillation h ad severe periventricular white matter lesions more than twice as often as subjects who did not (RR 2.2; 95% CI 1.0 to 5.2) but had no increased risk of subcortical white matter lesions (RR 1.1; 95% CI 0.4 to 2.6). For seven subjects with atrial fibrillation both at baseline and at follow up, these relative risks were 6.3 (95% CI 1.1 to 37.1) and 0.7 (95% CT 0.1 to 3.7). C onclusions: Atrial fibrillation is associated with periventricular white ma tter lesions, but not with subcortical white matter lesions.