Inclusion Criteria:  Atrial fibrillation recorded by 12-lead ECG or Holter that last for longer than 30 seconds within the preceding 6 months;  Eligible for left atrial appendage closure, that meet at least one of the followings:  At high risk of stroke (CHA2DS2-VASc score≥3 in female, ≥2 in male) and/or bleeding (HAS-BLED score≥3); Contraindicated to oral anticoagulation (OAC); Refused OAC treatment albeit comprehensively informed of the necessity and benefits of OAC treatment. Capable of understanding and signing the informed consent form. Aged over 18 years.  Exclusion Criteria:  Reversible causes of atrial fibrillation, including thyroid disorders, recent major surgery, trauma, acute alcoholic intoxication; Concomitant arrhythmia including atrial flutter, ventricular tachycardia; A previous history of atrial fibrillation surgery (MAZE surgery) or catheter ablation; A previous history of cardiac surgery including any valvular replacement, septal repair; A recent history of major cardiovascular disease within 3 months, including acute myocardial infarction, ventricular fibrillation; A history of congenital heart disease; A previous history of atrioventricular node ablation; A history of lobectomy due to any medical condition; Complicated by other diseases with life expectation <1 year; Women with childbearing potential; Participated in other interventional clinical trials that might affect prognosis; Unable to understand or give informed consent form.