SILENT CEREBRAL INFARCTION IN PATIENTS WITH NONRHEUMATIC ATRIAL-FIBRILLATION

Background Cerebral infarction in patients with atrial fibrillation ma y vary from being clinically silent to catastrophic. The prevalence of silent cerebral infarction and its effect as a risk factor for sympto matic stroke are important considerations for the evaluation of patien ts with atrial fibrillation. Methods and Results This Veterans Affairs cooperative study was a double-blind controlled trial designed primar ily to determine the efficacy of warfarin for the prevention of stroke in neurologically normal patients with nonrheumatic atrial fibrillati on. It also was designed to evaluate patients with silent cerebral inf arction. Computed tomography scans of the head were performed at entry , at the lime of any subsequent stroke, and at termination of follow-u p on all patients who completed the study without a neurological event . Of 516 evaluable scans performed at entry, 76 (14.7%) had evidence o f one or more silent cerebral infarcts. Age (P=.011), a history of hyp ertension (P=.003), active angina (P=.012), and elevated mean systolic blood pressure (P<.001) were associated with the presence of this fin ding. Silent cerebral infarction occurred during the study at rates of 1.01% and 1.57% per year for the placebo and warfarin treatment group s, respectively (NS). Silent cerebral infarction at entry was not an i ndependent predictor of later symptomatic stroke, but active angina wa s a significant predictor; 15% of the placebo-assigned patients with a ngina developed a stroke compared with 5% of the placebo-assigned pati ents without angina. Conclusions Silent cerebral infarction is frequen tly seen in asymptomatic patients with atrial fibrillation. Age, histo ry of hypertension, active angina, and elevated mean systolic blood pr essure were associated with silent infarction at entry, The sample siz e was too small to determine whether warfarin had an effect on the inc idence of silent infarction during the trial. Active angina at baselin e was the only significant independent predictor for the later develop ment of symptomatic stroke.