Inclusion Criteria:

1. Age ≥ 18 years and < 80 years at time of enrollment consent;
2. Left atrium ≤ 6.0 cm assessed with Transthoracic Echocardiography [TTE] with parasternal 4 chamber view or equivalent imaging modality;
3. Refractory or intolerant to at least one AAD (class I and/or III);
4. Subject has symptomatic (e.g. palpitations, shortness of breath, fatigue) longstanding persistent atrial fibrillation as defined by the 2017 HRS/EHRA/ECAS Guidelines (> 12 months of continuous AF);
5. Life expectancy > 12 months; and
6. Provides written informed consent.

Exclusion Criteria:

1. Patients requiring concomitant surgery such as valvular repair or replacement, coronary artery bypass graft (CABG) surgery and atrial septal defect closure;
2. Left ventricular ejection fraction < 35%;
3. Pregnant or planning to become pregnant during study;
4. Co-morbid medical conditions that limit one-year life expectancy;
5. Previous cardiac surgery;
6. History of pericarditis;
7. Previous cerebrovascular accident (CVA), excluding fully resolved TIA;
8. Patients who have active infection or sepsis
9. Patients with esophageal ulcers strictures and varices;
10. Patients with renal dysfunction who are not on dialysis (defined as GFR ≤ 40);
11. Patients who are contraindicated for anticoagulants such as heparin and coumadin;
12. Patients who are being treated for ventricular arrhythmias;
13. Patients who have had more than 2 prior left atrial catheter ablations for AF. NOTE: Note: Prior ablations should be limited to failed Pulmonary Vein Isolation (PVI) and no other left atrial lesions;
14. Current participation in another clinical investigation of a medical device or a drug, or recent participation in such a study within 30 days prior to study enrollment;
15. Not competent to legally represent him or herself (e.g., requires a guardian or caretaker as a legal representative);
16. Patient has presence of thrombus in the left atrium determined by intraoperative TEE;
17. Patient exhibits pulmonary vein stenosis in one or more of the pulmonary veins >50 % stenosis;
18. Planned Left Atrial Appendage Management (LAAM) with an endocardial implantable device during the course of the study;
19. Presence of other anatomic or comorbid conditions, or other medical, social, or psychological conditions that, in the investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with follow-up requirements, or impact the scientific soundness of the clinical investigation results
20. Presence of Barretts esophagitis

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 10/24/2024. Questions regarding updates should be directed to the study team contact.