Eligibility CriteriaInclusion criteria:
1. A. Written informed consent prior to participation
2. A. Female and male patients >= 18 years of age with a diagnosis of non-valvular atrial fibrillation.
3. A. At least 3 months of continuous VKA treatment for stroke prevention prior to baseline assessment.
4. A. Patients switched to Pradaxa according Summary of Product Characteristics and physician`s discretion.
1. B. Written informed consent prior to participation.
2. B. Female and male patients >= 18 years of age newly diagnosed with non-valvular atrial fibrillation and no previous treatment for stroke prevention (no use of any oral anticoagulant (OAC) within one year prior to enrolment).
3. B. Stroke prevention treatment initiated with Pradaxa or VKA according to Summary of Product Characteristics and physician`s discretion.
1. Contraindication to the use of Pradaxa or VKA as described in the Summary of Product Characteristics (SmPC).
2. Patients receiving Pradaxa or VKA for any other condition than stroke prevention in atrial fibrillation.
3. Current participation in any clinical trial of a drug or device.
4. Current participation in an European registry on the use of oral anticoagulation in AF.