This registry is designed to observe the safety and effectiveness of WATCHMAN left atrial appendage closure technology in a Chinese population.

In this prospective, multi-center, single arm observational study, 413 patients with non-valvular atrial fibrillation intended to be implanted with a WATCHMAN device based on real clinical practice will be enrolled. Enrolled subjects will be followed up for 5 years.Primary endpoints include stroke, systematic embolism, cardiovascular death, and procedure or device related complications, etc.

Inclusion Criteria:

Non-valvular atrial fibrillation patient with CHA2DS2-VASC≥2, and with any one of the following items:

1. not suitable for long-term anti-coagulation therapy;
2. stroke or embolism events in spite of warfarin treatment with intended INR
3. HAS-BLED≥3

Exclusion Criteria:

Patient with any one of the following items will be excluded from the study:

1. clinical exclusion criteria (any of the items) a congestive heart failure NYHA IV, b atrial septum defect, ASD surgery or closure c cardioversion or catheter ablation is planned within 30 days d with mechanic valve e left atrial appendage resection f heart transplantation g symptomatic jugular artery disease h previous stroke or TIA within 30 days i long term warfarin therapy is needed or contraindicated to warfarin j contraindicated to aspirin or clopidogrel k enrolled in other cardiac device or medicine trials l pregnant women or plan to pregnant during the study period m estimated life < 5 years

2 Echocardiography exclusion criteria (any of the items) a LVEF<30% b thrombus or spontaneous echo imaging detected within two days prior to procedure c patent foramen ovale d cardiac tumor e left atrial appendage orifice diameter >32mm or < 17mm f the depth of left atrial appendage is less than the width g prominent mitral stenosis (area <1.5cm2)

3 subject is not able to or will not complete the follow ups as planned

non-valvular atrial fibrillation