Recent publications suggest that neither empirical nor individualized substrate modification strategies could improve single-procedure efficacy beyond pulmonary vein (PV) isolation for persistent atrial fibrillation (AF). However, persistent AF represent a broad spectrum of the same disease and if PV isolation may be sufficient for some patient with self-terminated AF or with a small left atrium, a more extended substrate ablation may be required for other patients, for which a second procedure for atrial tachycardia (AT) recurrence is then frequently needed. In addition, a lot of progress has recently been made in the field of ablation techniques using contiguous and optimized ablation radiofrequency (RF) lesions and also for AT mapping with promising results using repetitive but discontinuous Holter monitoring.

This trial aims at

1. To objectively compare atrial tachyarrhythmia (ATA) burden > 2 months before ablation and after one or two 'CLOSEMAZE'-guided ablation(s) using continuous monitoring and echo data as a guide for the ablation strategy during the first ablation.
2. To assess ATA burden using continuous monitoring up to 3 years after ablation.
3. To identify baseline structural and electrical properties of the atria or procedural characteristics that predict 1-year and 3-year outcome.

Inclusion Criteria

1. Patients with symptomatic persistent AF (history of continuous AF > 7 days), meeting following criteria at the out-patient clinic:

   • patient has AF at the time of the visit
   • AF episodes are symptomatic, and patient is drug-resistant (at least one class Ic or III), or drug-intolerant (palpitations, fatigue, dyspnea, cardiomyopathy,…)
   • If the patient has heart failure (LVEF<50%), first line AF ablation (instead of amiodarone) is indicated

2. Signed Patient Informed Consent Form.

3. Age 18 years or older.

4. Able and willing to comply with all follow-up testing and requirements.

Exclusion Criteria

1. Longstanding persistent atrial fibrillation (Suspected continuous AF>1 year)
2. Previous ablation for AF
3. left atrial antero-posterior diameter > 55 mm (parasternal long axis view (PLAX))
4. LVEF < 30% (ejection fraction)
5. AF secondary to electrolyte imbalance, thyroid disease, or reversible or non-cardiac cause
6. Coronary artery bypass graft within the last three months
7. Awaiting cardiac transplantation or other cardiac surgery
8. Documented left atrial thrombus on imaging
9. Diagnosed atrial myxoma
10. Women who are pregnant or breastfeeding
11. Acute illness or active systemic infection or sepsis
12. Unstable angina
13. Uncontrolled heart failure
14. Myocardial infarction within the previous two months
15. History of blood clotting or bleeding abnormalities
16. Contraindication to anticoagulation therapy (ie, heparin or warfarin)
17. Life expectancy less than 12 months
18. Enrollment in any other study evaluating another device or drug
19. Presence of intramural thrombus, tumor or other abnormality that precludes catheter introduction