Assessment of the WATCHMAN™ Device in Patients Unsuitable for Oral Anticoagulation

Inclusion Criteria: * The subject is of legal age to participate in the study per the laws of their respective geography. * The subject has documented paroxysmal, persistent, permanent or long-term/longstanding persistent non-valvular atrial fibrillation (i.e., the subject has not been diagnosed with rheumatic mitral valvular heart disease). * The subject has a calculated CHA2DS2-VASc score of 2 or greater. * The subject is deemed by two study physicians to be unsuitable for oral anticoagulation. * The subject is deemed by a study physician to be suitable for the defined protocol pharmacologic regimen of aspirin and clopidogrel therapy following WATCHMAN Closure Device implant. * The subject or legal representative is able to understand and willing to provide written informed consent to participate in the trial. * The subject is able and willing to return for required follow-up visits and examinations. Exclusion Criteria: * The subject is unable or unwilling to return for required follow-up visits and examinations. * The subject had or is planning to have any invasive cardiac procedure within 30 days prior to randomization (e.g., cardioversion, ablation). * The subject is planning to have any cardiac or non-cardiac invasive or surgical procedure that would necessitate stopping or modifying the protocol required medication regimen within 90 days after the WATCHMAN Closure Device implant (e.g., cardioversion, ablation, cataract surgery). * The subject had a prior stroke (of any cause) or TIA within the 30 days prior to randomization. * The subject had a prior BARC type 3 or 4 bleeding event within the 14 days prior to randomization. Lack of resolution of related clinical sequelae, or planned and pending interventions to resolve bleeding/bleeding source, are a further exclusion regardless of timing of the bleeding event. * The subject has a history of atrial septal repair or has an ASD/PFO device. * The subject has an implanted mechanical valve prosthesis in any position. * The subject suffers from New York Heart Association Class IV Congestive Heart Failure. * The subject has LVEF \< 30%. * The subject is of childbearing potential and is, or plans to become pregnant during the time of the study (method of assessment upon study physician's discretion). * The subject is currently enrolled in another investigational study or registry that would directly interfere with the current study, except when the subject is participating in a mandatory governmental registry, or a purely observational registry with no associated treatments. Each instance should be brought to the attention of the sponsor to determine eligibility. * The subject has a life expectancy of less than two years. * The subject has a known or suspected hypercoagulable state.