LAMax Vs. Watchman LAAC Device for Subjects With Non-valvular AF to Reduce the Risk of Stroke

Inclusion Criteria: * Patients ≥ 18 years old with non-valvular atrial fibrillation (AF) and CHA2DS2-VASc ≥2 * There is one of the following: (1) Not suitable for long-term standard anticoagulation treatment; (2) On the basis of long-term standardized anticoagulant therapy with warfarin, stroke or embolism still occurred; (3) HAS-BLED ≥ 3. * Provide written informed consent and agree to comply with required follow-ups. Exclusion Criteria: 1. . Patients with other diseases other than AF who need long-term warfarin anticoagulation therapy; 2. . Those who need selective cardiac surgery; 3. . Heart failure NYHA grade IV; 4. . AF caused by rheumatic valvular disease, degenerative valvular disease, congenital valvular disease, severe mitral stenosis, aortic stenosis, or other valvular diseases; 5. . The early onset of AF and paroxysmal AF with definite causes, such as secondary to coronary artery bypass grafting (CABG), hyperthyroidism; 6. . Patients with symptomatic carotid artery disease (such as carotid stenosis \> 50%); 7. . Patients with acute myocardial infarction, unstable angina, or recent myocardial infarction \< 3 months; 8. . Stroke or TIA within 30 days; 9. . Bleeding disease, coagulation-related diseases, and active peptic ulcer; 10. . Active endocarditis, vegetations, or other infections causing bacteremia or sepsis; 11. . Conditions may lead to difficulty in testing or significantly shorten the life expectancy of patients (\< 1 year); 12. . Pregnant, lactating or planned pregnancy during the trial; 13. . Patients who have not reached the end of other clinical trials of drug or device; 14. . Hematological abnormality (WBC \< 3 × 109 / L, HB \< 90g / L, or platelet count \< 50 × 109 / L or \> 700 × 109 / L)); 15. . Renal insufficiency (creatinine \> 3.0mg/dl or 265.2umoi / L), and / or advanced renal diseases requiring dialysis; 16. . Severe liver dysfunction (AST / ALT is 5 times higher than the upper limit of normal value, or total bilirubin is 2 times higher than the upper limit of normal value); 17. . The investigator believes that the patient is not suitable to participate in the clinical trial. 18. . Left atrial appendage has been removed, post heart transplantation, post atrial septal repair, or post occluder implantation; 19. . Radiofrequency ablation in 30 days before and after the implantation of LAA occluder; 20. . Cardioversion within 30 days after the implantation of LAA occluder; 21. . Post prosthetic heart valve replacement; 22. . Allergic to or contraindication to metal nickel alloy, aspirin, clopidogrel, contrast agent, heparin and other anticoagulants, etc; 23. . Patients who have placed other instruments in the cardiovascular cavity and are unable to place the LAA occluder; 24. . LVEF（left ventricular ejection fraction ）\<35%； 25. . Clear thrombus is found in the heart before device implantation; 26. . TEE examination: refer to Watchman LAAC requirement to measure the orifice diameter of LAA, the maximum diameter is less than 17 mm, or more than 31 mm; 27. . Patent foramen ovale with high risk; 28. . mitral stenosis with a valve area ≤ 2 cm2; 29. . left atrial diameter \> 65mm, or pericardial effusion more than a small amount, the depth of local effusion \> 10 mm; 30. . Contraindications to X-ray, or not suitable for TEE examination.