Inclusion Criteria:  The patients is eligible to undergo WATCHMAN device implant procedure. The patient is eligible for short term anticoagulation therapy. Ability to tolerate the procedure without the need for general anesthesia as assessed by the treating physician(s). Ability to give informed consent for the procedure. The patient is able and willing to undergo the procedure under moderate sedation. The patient is able and willing to return for required 45-day TEE.  Exclusion Criteria:  Patient has contraindication for short term anticoagulation. The patient has history of a hypercoagulable state per medical record documentation. Pregnancy or planning to get pregnant during the investigation.