Safety and Effectiveness of STSF Catheter Evaluated for Treating Symptomatic Persistent Atrial Fibrillation (PsAF)

Inclusion Criteria: Candidates for this study must meet ALL of the following criteria: 1. Documented symptomatic persistent AF, which is defined as continuous AF sustains beyond 7 days and less than 1 year and is documented by the following:. 1. Physician's note indicating continuous AF ≥ 7 days but no more than 1 year; AND 2. Two electrocardiograms (from any forms of rhythm monitoring) showing continuous AF, with electrocardiogram taken at least 7 days apart OR 3. 24-hour Holter within 90 days of the ablation procedure showing continuous AF 2. Failed at least one antiarrhythmic drug (AAD) (class I or III) as evidenced by recurrent symptomatic AF, or intolerable to the AAD. 3. Age 18 years or older. 4. Signed Patient Informed Consent Form (ICF). 5. Able and willing to comply with all pre-, post-, and follow-up testing and requirements. Exclusion Criteria: Candidates for this study will be EXCLUDED from the study if ANY of the following conditions apply: 1. Continuous AF \> 12 months (1-Year) (Longstanding Persistent AF) 2. Previous surgical or catheter ablation for atrial fibrillation 3. Any cardiac surgery within the past 2 months (60 days) (includes percutaneous coronary intervention (PCI)) 4. Coronary Artery Bypass Graft (CABG) surgery within the past 6 months (180 days) 5. Valvular cardiac surgical/percutaneous procedure (i.e., ventriculotomy, atriotomy, and valve repair or replacement and presence of a prosthetic valve) 6. Any carotid stenting or endarterectomy 7. Documented left atrial (LA) thrombus on imaging 8. LA size \> 50 mm (parasternal long axis view) 9. Left ventricular ejection fraction (LVEF) \< 40% 10. Contraindication to anticoagulation (heparin or warfarin) 11. History of blood clotting or bleeding abnormalities 12. MI within the past 2 months (60 days) 13. Documented thromboembolic event (including Transient Ischemic Attack (TIA) within the past 12 months (365 days) 14. Rheumatic Heart Disease 15. Uncontrolled heart failure or New York Heart Association (NYHA) function class III or IV 16. Severe mitral regurgitation (Regurgitant volume ≥ 60 mL/beat, Regurgitant fraction ≥ 50%, and/or Effective regurgitant orifice area ≥ 0.40cm2) 17. Awaiting cardiac transplantation or other cardiac surgery within the next 12 months (365 days) 18. Unstable angina 19. Acute illness or active systemic infection or sepsis 20. AF secondary to electrolyte imbalance, thyroid disease, or reversible or non-cardiac cause. 21. Diagnosed atrial myxoma. 22. Presence of implanted implantable cardioverter defibrillator (ICD) /cardiac resynchronization therapy defibrillator (CRT-D). 23. Significant pulmonary disease, (e.g., restrictive pulmonary disease, constrictive or chronic obstructive pulmonary disease) or any other disease or malfunction of the lungs or respiratory system that produces chronic symptoms. 24. Gastroesophageal Reflux Disease (GERD; active requiring significant intervention not including over-the-counter (OTC) medication) 25. Significant congenital anomaly or medical problem that in the opinion of the investigator would preclude enrollment in this study. 26. Women who are pregnant (as evidenced by pregnancy test if pre-menopausal) 27. Enrollment in an investigational study evaluating another device, biologic, or drug. 28. Presence of intramural thrombus, tumor or other abnormality that precludes vascular access, or manipulation of the catheter. 29. Presence of any other condition that precludes appropriate vascular access. 30. Life expectancy less than 12 months