Clinical Investigation of the LAmbre Left Atrial Appendage Closure System

Inclusion Criteria: * Age ≥18 years * Patients scheduled for interventional closure of the left atrial appendage (LAA) due to a high thromboembolic risk and cannot be treated with anticoagulation. * Chronic atrial fibrillation ≥3 months; paroxysmal, persistent or permanent nonvalvular Atrial Fibrilation (AF) * CHA2DS2 -VASC score 2 or higher * Eligible for clopidogrel and aspirin * Able to understand the requirements of the study and willing to follow study instructions, provide written informed consent, and agree to comply with all study requirements, including the required study follow-up visits Exclusion Criteria: * Presence of rheumatic, degenerative or congenital valvular heart diseases * Presence of rheumatic, degenerative or congenital valvular heart diseases * The diameter of left atrium ≥65 mm * LAA Ostium \< 12mm or \> 30 mm * Prior surgical removal of Left atrium * Prior heart transplant * Symptomatic patients with carotid artery disease (such as carotid stenosis ≥ 50%) * Recent or acute myocardial infarction (MI) or unstable angina (recent is defined as within 3 months of implant date) * Decompensated heart failure (NYHA grade III-IV) * Patients have an electrophysiological ablation procedure planned within 30 days of potential the LAmbreTM Left Atrial Appendage Closure System implant date * Patients have a planned electrophysiologic 30 days post implantation of the LAmbreTM Left Atrial Appendage Closure System * Patients have a planned cardioversion 30 days post implantation of the LAmbreTM Left Atrial Appendage Closure System * Patients with a history of heart valve replacement operation with an mechanical prosthesis * History of stroke or Transient Ischemic Attack (TIA) within 30 days * Have thrombocytopenia (platelet ≤ 100.000 platelets per microliter (mcL)) * Heart rate in rest \> 110 beats per minute (BPM) * A single episode of transient atrial fibrillation * Pericardial effusion \> 5mm pre-procedural * Presence of active sepsis or endocarditis * Cardiac tumors or other malignancy with estimated life expectancy less than 2 years * Patients who are pregnant, breastfeeding, or desires to become pregnant during the course of the study * Participation in the other investigational trials in which the primary endpoint is not met yet * Subject dependency of the Sponsor, of the institution in which the trail is conducted, or of the investigator * Investigator expectation that the patient will not be able to complete the trial according to the requirements * A known allergy to nitinol Esophageal ultrasonic exclusion criteria * LVEF ≤ 30 % * Presence of thrombus in the left atrial appendage (LAA) * Patent Foramen Ovale (PFO) with history of paradoxical embolism * Mitral valve stenosis (Mitral valve area ≤ 2 cm2) * Presence of complex aortic plaque (≥4mm) in ascending aorta