Contribution of atrial fibrillation to incidence and outcome of ischemic stroke. Results from a population-based study

Abstract BACKGROUND AND PURPOSE: Atrial fibrillation (AF) is a major risk factor for ischemic stroke and its prevalence increases steeply with age. Population-based data on its influence on stroke outcome are scarce. METHODS: We evaluated the prevalence of AF and its influence on prognosis in patients with a first-ever ischemic stroke from a population-based registry. RESULTS: The presence of AF at stroke onset and during the acute phase was confirmed by a standard electrocardiogram in 869 (24.6%) of 3530 patients with ischemic stroke. With respect to patients without the arrhythmia, those with AF were more frequently women, aged 80 years and older, with coronary heart disease and peripheral arterial disease. The presence of AF was associated with high 30-day (32.5%; 95% CI, 29.3 to 35.6) and 1-year case-fatality rates (49.5%; 95% CI, 46.2 to 52.8), with a higher stroke recurrence rate within the first year of follow-up (6.6% versus 4.4%; P=0.046) and with the worst survival after an average follow-up of 45.2 months (P<0.0001). At the multivariate Cox regression analysis, AF was an independent predictor of 30-day and 1-year mortality. Approximately 17% of all deaths were attributable to the presence of AF. CONCLUSIONS: We found a high prevalence of AF in patients with a first-ever ischemic stroke, especially among elderly women. The overall contribution of AF to stroke mortality was relevant, suggesting that together with new strategies to prevent the development of the arrhythmia more appropriate treatments are needed, mostly in elderly women.