Endocardial Mapping with the CoreMap EP Mapping System

Inclusion Criteria:

1. Subject has persistent or long-standing persistent AF, at the discretion of theinvestigator

2. Subject is 18 to 80 years of age

3. Patient scheduled for standard of care AF ablation

4. Subject is able to provide written informed consent

5. Subject is able and willing to complete all study procedures

Exclusion Criteria:

1. Any of the following within three months of enrollment:

2. Myocardial infarction (MI)

3. Any surgical or percutaneous cardiac procedure including coronary interventionand cardiac ablation

4. Confirmed thrombus on imaging

5. Any of the following within six months of enrollment: a) Cardiac surgery includingcoronary artery bypass grafting, ventriculotomy, atriotomy b) Thromboembolic event (stroke)

6. Any of the following cardiac conditions:

7. New York Heart Association (NYHA) IV

8. Left ventricular ejection fraction (LVEF) < 30%

9. Carotid stenting or endarterectomy

10. Atrial or ventricular septal closure or left atrial appendage closure

11. Implanted permanent pacemaker, biventricular pacemaker, or any type ofimplantable cardiac defibrillator

12. Presence of intramural thrombus, tumor (including atrial myxoma), or otherabnormality that precludes vascular access, catheter introduction, ormanipulation

13. Unstable angina

14. Prior mitral or tricuspid valve surgery, repair, prosthetic or mechanical valve

15. Moderate to severe mitral valve stenosis or other severe valvular disease

16. Any blood clotting or bleeding abnormalities

17. Contraindication to systemic anticoagulation

18. AF secondary to electrolyte imbalance, acute alcohol intoxication, or reversible ornon-cardiac cause

19. Body mass index (BMI) > 40 kg/m2

20. Severe pulmonary disease, pulmonary hypertension, or any chronic respiratorycondition

21. Renal failure requiring dialysis or transplant

22. Acute illness, active systemic infection, or sepsis

23. Active drug or alcohol dependency

24. Any contra-indication that may extend procedure time, at the discretion of theoperator

25. Any woman known to be pregnant or breastfeeding, or any woman of childbearingpotential who is not on a reliable form of birth regulation method or abstinence

26. Subject considered part of vulnerable population

27. Life expectancy less than one year

28. Employee of the study site or Sponsor

29. Subjects who are currently enrolled in another study that would directly interferewith this study