Læknablaðið 2004; 90: 561-65

Objective: Atrial fibrillation (AF) is the most common sustained cardiac arrythmia and a significant cause of morbidity. Stroke and transient ischemic attack (TIA) are well known serious complications of AF. In the last decade, a number of studies have shown that the risk of stroke in patients with AF is reduced by anticoagulation therapy with warfarin. The aim of this study was to assess the prevalence of AF in patients with acute ischemic stroke or TIA and to look at the use of anticoagulation therapy in patients who either had a previously known AF or were diagnosed to have AF during hospitalisation for ischemic stroke or TIA.

Methods: Medical records of 918 patients admitted to Landspitali University Hospital in Iceland in 1997-2000 with the diagnosis of TIA or ischemic stroke were reviewed to detect a subgroup with AF. In addition to demographic data and cardiac function studies, information was collected about other possible coexisting stroke risk factors.

Results: A total of 159 patients (17%) had AF in 124 (78%) of whom the AF was previously known. In 35 patients AF was diagnosed during the hospitalisation.The majority of those patients also had at least one other risk factor for stroke. On admission, 27 patients (22%) of those with previously known AF were being treated with warfarin. In eleven (41%) the anticoagulation was subtherapeutic as the INR was found to be lower than 2,0. At discharge, 74 patients of those 131 (56%) who were alive were receiving warfarin anticoagulation.

Conclusion: The prevalence of AF in patients with TIA or ischemic stroke was somewhat high in this study. AF and other risk factors for stroke were found to commonly coexist. Despite the well documented effect of warfarin in such patients, this therapy was underused for both primary and secondary stroke prevention.