Atrial Fibrillation as a Cause of Stroke and Intracranial Hemorrhage Study (The FibStroke Study)

The aim of this study is to evaluate the role of atrial fibrillation (AF) and its treatment in relation to thromboembolic events (stroke, and transient ischemic attacks) and intracranial hemorrhage. Primary Outcome Measures: \- Incidence and timing of intracranial complications (stroke,TIA, bleedings) in relation to diagnosis and anticoagulation treatment of AF during the study period; comparison of complications between those with and without anticoagulation treatment according to CHADSVASc score. Secondary Outcome Measures: * The effect of anticoagulation pauses and INR level on stroke and bleeding risk; strokes within 30 days after anticoagulation pause and the prevalence of stroke and intracranila bleeding in relation to INR level \3. * Trauma as a risk factor for intracranial bleeding: percentage and risk factors for intracranial bleeding with or without trauma. Type of preceding trauma and type of intracranial bleeding. * The time relation between diagnosis of AF and type of intracranial complications: Kaplan Meier analysis of thrombotic (Stroke/TIA) and intracranial bleeding complications after 1st diagnosis of AF in patients with and without anticoagulation * The risk of stroke and intracranial bleeding in relation to CHADSVASc score, HAS-BLED score and anticoagulation/antithrombotic treatment * Prognosis of stroke and intracranial bleeding: 30-day mortality after stroke and intracerebral bleeding in patients with and without anticoagulation * Factors related to underuse of anticoagulation treatment. Data on reasons for not starting or stopping aticoagulation in those with indication of oral anticoagulation * Operations and procedure as risk factor for stroke: Frequency and type of operations performed \< 30 days before stroke. Data on length of perioperative pause in anticoagulation and use of bridging therapy and timiing of stroke are collected. * Cardioversions as a risk factor for stroke: Frequency of stroke and TIA \< 30 days after ca