This is a prospective, randomized (2:1) multicenter trial to investigate the optimal treatment of Persistent and Longstanding Persistent AF referred for Radiofrequency (RF) ablation.The study objective is to compare the efficacy and safety of two interventional approaches, in preventing the recurrence of AF in symptomatic, drug refractory patients with persistent or longstanding persistent atrial fibrillation.

Inclusion Criteria:

1. Patient has a history of symptomatic Persistent AF and a left atrium (LA) > 4cm or Long Standing Persistent AF as defined by the HRS/EHRA/ECAS expert consensus statement
2. Patient is refractory to or intolerant of at least one antiarrhythmic drug (class I or III)
3. Patient is mentally able and willing to give informed consent

Exclusion Criteria:

1. Patient has longstanding persistent AF > 10 years
2. Patient presenting with paroxysmal AF
3. Patient with persistent AF and a LA-diameter ≤ 4cm
4. AF is secondary to electrolyte imbalance, thyroid disease, or other reversible or non-cardiovascular cause
5. Patient underwent previous ablation procedure or heart surgery
6. Patient needs other cardiac surgery procedures besides AF treatment (valve, coronary, others)
7. Contraindication for either catheter ablation or epicardial surgery (including, but not limited to: previous thoracic radiation, previous perimyocarditis, Previous cardiac tamponade, Pleural adhesions, Prior thoracotomy)
8. Body mass index > 35
9. LA Diameter > 6 cm
10. Left ventricular ejection fraction < 30 %
11. Severe mitral regurgitation (>II)
12. Patient unable to undergo TransEsophageal Echocardiogram (TEE)
13. Presence of LA thrombus by TEE, CT scan, MRI or angiography
14. History of cerebrovascular disease, including stroke or transient ischemic attack (TIA) within 6 months prior to enrollment
15. Active infection or sepsis
16. Other clinical conditions precluding inclusion (e.g., organ disease, disturbances of hemostasis)
17. Contraindication to anticoagulant therapy, or inability to comply with anticoagulant therapy
18. Pregnancy, planned pregnancy or breastfeeding
19. Life expectancy is less than 12 months
20. Patient is involved in another study involving an investigational drug or device