Inclusion Criteria:
Subjects must meet all of the following criteria:
1. Non-Paroxysmal Atrial Fibrillation.
2. Failed or intolerable to at least 1 one antiarrhythmic drug (AAD).
3. 18-85 year of age at time of consent.
4. Scheduled to undergo a clinically indicated AF ablation procedure.
5. Able and willing to comply with all protocol visit requirements.
6. Signed Patient Informed Consent (ICF).
7. Presence of low voltage in the left atrium on 3-D map during index catheter ablation procedure
Exclusion Criteria:
Subjects will be excluded if any of the follow criteria are present:
1. History of prior left-sided catheter or surgical ablation for AF or atypical atrial flutter, including MAZE or mini MAZE.
- Prior ablation for typical atrial flutter or left-sided ablation for WPW, AV node reentry tachycardia or focal ectopic atrial tachycardia may be included.
2. Uncontrolled heart Failure or NYHA Class IIIb or IV heart failure.
3. Ejection Fraction < 0.20.
4. Active ventricular tachycardia requiring treatment with catheter ablation or anti-arrhythmic drug within the last 6 months.
5. Left atrial size > 60 mm diameter on echocardiogram.
6. "Long standing" persistent AF defined as > or = 1 year of continuous atrial fibrillation at the time of enrollment.
7. Severe pulmonary hypertension (PAP > 70 mmHg)
8. Unstable valvular disease.
9. AF secondary to electrolyte imbalance, thyroid disease or reversible non- cardiac cause.
10. Poor candidate for general anesthesia.
11. Anticipated survival < 1 year.
12. MI or CABG within 3 months.
13. Left atrial thrombus in pre-procedure imaging within 4 weeks of the ablation procedure.
14. Any documented thromboembolic event within 6 months of the ablation procedure.
15. Contraindication to anticoagulation.
16. Inability to have implantable monitoring device for atrial fibrillation burden with no pre-existing cardiac device that can monitor atrial arrhythmias OR inability to wear external Holter Monitor continuously for 4 weeks.
17. Significant congenital anomaly or medical condition that may affect the integrity of study data.
18. Women who are pregnant - pregnancy test required if pre-menopausal or non-sterile.
19. Active enrollment in another investigational study involving a drug or device.
20. Inability to undergo complete voltage mapping in normal sinus rhythm - see intraprocedural protocol.
21. Presence of any medical or psychological condition or medical non-compliance history that may adversely impact study outcomes.