Left Atrial Appendage Occlusion and Biomarker Evaluation

Inclusion Criteria: * non valvular atrial fibrillation, that makes anticoagulation to prevent embolic stroke from the LAA * contraindication for the therapy with oral anticoagulants: * refusal to take oral anticoagulation * HasBled-score more than 3 * prior bleedings under oral anticoagulation Exclusion Criteria: * under 18 years * severely reduced left atrial function * mechanical heart valve * pulmonary embolism * deep vein thrombosis * myocardial infarction within the last 3 months * electrical cardioversion within 30 days after potential occluder implantation * atrial septum defect or interventional/surgical occlusion of ASD * status after heart transplant * symptomatic carotid artery stenosis * transient ischemic attack (TIA) or stroke within last 30 days * intracerebral bleeding within the last 2 months * acute infection * existing or planned pregnancy