The primary safety endpoint consists of the following serious adverse events within 30 days post-index procedure (unless otherwise noted), as adjudicated by Independent Physician Adjudicator: * Serious Injury to the cardiac structure or other body structure deemed to be related to the delivery or placement of the Clip * Cardiac-Related Death, Myocardial Infarction, or Ischemic Stroke * Major bleeding (defined as requiring re-operation and/or transfusion (\> 2 U packed red blood cells (PRBC)) within any 24 hour period during the first 2 days post-index procedure or at any time point if attributed to the device/index procedure).

Primary Efficacy endpoint is a success/failure endpoint with success requiring all of the following: 1. Patient Technical Success: The ability to successfully implant an AtriClip device at the LAA in a patient. 2. Intra-Procedural Complete Exclusion of the LAA: The complete exclusion of the LAA defined by lack of fluid communication (\<3 mm residual communication with LAA and \<10 mm residual pocket) between the LA and LAA, assessed intra-procedurally by TEE. 3. 3 Month Follow-Up Complete Exclusion of the LAA: The complete exclusion of the LAA defined by lack of fluid communication (\<3 mm residual communication with LAA and \< 10mm residual pocket) between the LA and LAA at \>=3 month TEE or CTA evaluation.