The Left Atrial Appendage Occlusion Registry (LAAO Registry™) is designed to assess the prevalence, demographics, management, and outcomes of patients undergoing percutaneous and epicardial based left atrial appendage occlusion procedures to reduce the risk of stroke. Patient-level data will be submitted by participating hospitals on a quarterly basis to the American College of Cardiology Foundation's National Cardiovascular Data Registry (NCDR). The primary aims of the LAAO Registry are to optimize the outcomes and management of patients through the implementation of evidence-based guideline recommendations in clinical practice, facilitate efforts to improve the quality and safety for patients undergoing percutaneous and epicardial based left atrial appendage procedures, investigate novel quality improvement methods and provide risk-adjusted assessment of patients for comparison with nationwide NCDR data. The secondary purpose of the LAAO Registry is to serve as a rich source of clinical data to support assessments of short- and long-term safety, comparative and cost effectiveness research, and as a scalable data infrastructure for post market studies.