A Pilot Study to Assess WATCHMAN FLX™ Implants by Cardiac Computed Tomography, Magnetic Resonance Imaging and Transesophageal Echocardiography: WATCHMAN FLX™ CT

Inclusion Criteria:

1. Subject is of legal age to participate in the study per the laws of their respective geography.
2. Subject has documented non-valvular atrial fibrillation (i.e., atrial fibrillation in the absence of moderate or greater mitral stenosis or a mechanical heart valve).
3. Subject is clinically indicated for a WATCHMAN FLX device.
4. Subject is deemed suitable for the protocol-defined pharmacologic regimen.
5. Subject or legal representative is able to understand and willing to provide written informed consent to participate in the study.
6. Subject is able and willing to return for required follow-up visits and examinations.

Exclusion Criteria:

1. Subject is currently enrolled in another investigational study, except if the subject is participating in a mandatory governmental registry, or a purely observational registry with no associated treatment.
2. Subject has eGFR <30 mL/min (chronic kidney disease stage IV or stage V).
3. Subject is contraindicated for TEE.
4. Subject requires long-term anticoagulation therapy for reasons other than AF-related stroke risk reduction (e.g., due to an underlying hypercoagulable state).
5. Subject had or is planning to have any cardiac or non-cardiac intervention or surgical procedure within 30 days prior to or 60 days after implant (including, but not limited to, cardioversion, percutaneous coronary intervention, cardiac ablation, cataract surgery, etc.).
6. Subject had a prior stroke (of any cause, whether ischemic or hemorrhagic) or transient ischemic attack (TIA) within the 30 days prior to enrollment.
7. Subject had a prior major bleeding event per ISTH definitions within the 30 days prior to enrollment. 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.
8. Subject has an active bleed.
9. Subject has a reversible cause for AF or has transient AF.
10. Subject has no LAA or the LAA is surgically ligated.
11. Subject has had a myocardial infarction (MI) documented in the clinical record as either a non-ST elevation MI (NSTEMI) or as an ST-elevation MI (STEMI), with or without intervention, within 30 days prior to enrollment.
12. Subject has a history of atrial septal repair or has an atrial septal defect/patent foramen ovale (ASD/PFO) device.
13. Subject has a known contraindication to percutaneous catheterization procedure.
14. Subject has a cardiac tumor.
15. Subject has signs/symptoms of acute or chronic pericarditis.
16. Subject has an active infection.
17. There is evidence of tamponade physiology.
18. Subject has New York Heart Association Class IV congestive heart failure at the time of enrollment.
19. Subject is of childbearing potential and is, or plans to become, pregnant during the time of the study (method of assessment per study physician's discretion).
20. Subject has a documented life expectancy of less than 6 months.