Although the additional linear ablation after pulmonary vein isolation (PVI) is a class IIB indication for AF catheter ablation in patients with persistent AF, no clear benefit has been demonstrated in the recent randomized clinical trials (STAR-AF2 or POBI trials). Nevertheless, in the retrospective cohort data of this research team, additional POBI and AL were helpful in persistent AF patients with left atrial (LA) size > 50mm or more or low LA voltage. The purpose of this study was to evaluate the efficacy and safety of additional POBI and AL compared to CPVI alone in persistent AF patients with LA size over 50mm. Also, we intend to proceed with this randomized clinical trial with the high power short duration ablation protocol, which is effective in shortening the procedure time.

A. Study design

1. Prospective randomization (pulmonary vein isolation [PVI] group vs. additional posterior box isolation [POBI] group vs. additional POBI and anterior line [AL] group)
2. Target number of subjects: 480 (160 per group)
3. Rhythm follow-up : 2012 ACC/AHA/ESC guidelines (Holter monitoring at the baseline, 2 month, and thereafter every 6 months; ECG if the patient has any symptom)
4. Anticoagulant therapy followed by 2014 ACC/AHA/ESC guidelines
5. All complications in each group will be evaluated including the re-hospitalization rate, major cardiovascular event, and mortality rate.

B. Progress and rhythm/ECG follow-up

1. To be performed in accordance with the 2012 ACC/AHA/HRS guidelines for AF management
2. Follow-up at 1 weeks, 3 months, and thereafter every 6-month after procedure.
3. Rhythm control at 3 months, and thereafter every 6-month follow-up with Holter
4. If the patient complains of symptoms, ECG will be performed at any time, and rhythm follow-up will be carried out with a Holter or event recorder.

C. Follow-up All the patients will be followed-up at 1, 3, 6 months, and thereafter every 6 months. If the patient shows any symptom within the clinical study period, patient will visit the outpatient clinic. ECG will be performed at every outpatient visits, and 24-hour Holter or event recording will be performed every 6 months for 2 years, and every year after 2 years (2012 Heart Rhythm Society/EHRA/European Cardiac Arrhythmia Society Expert Consensus Statement guidelines). If atrial fibrillation or atrial tachycardia lasting more than 30 seconds is observed in 12-lead ECG or Holter, it will be evaluated as recurrence. Recurrence within 3 months after the procedure will be classified as early recurrence, and that after 3 months will be classified as clinical recurrence.

Inclusion Criteria:

1. Patient with persistent atrial fibrillation who is scheduled for ablation procedure and ≥20 and ≤80 years of age
2. Left atrium size ≥ 50mm
3. Persistent atrial fibrillation that is recurrence during antiarrhythmic drug treatment or is not able to use an antiarrhythmic drug.
4. Patient who is indicated for anticoagulation therapy (for prevention of cerebral infarction)

Exclusion Criteria:

1. AF Patients with LA size less than 50mm
2. Atrial fibrillation associated with severe cardiac malformation or a structural heart disease that is hemodynamically affected
3. Patients with severe renal impairment or CT imaging difficulty using contrast media
4. Patients with a past history of radiofrequency ablation for atrial fibrillation or other cardiac surgery
5. Patients with active internal bleeding
6. Patients with contraindications for anticoagulation therapy(for prevention of cerebral infarction) and antiarrhythmic drugs
7. Patients with valvular atrial fibrillation (mitral stenosis >grade 2, mechanical valve, mitral valvuloplasty)
8. Patients with a severe comorbid disease
9. Expected survival < 1 year
10. Drug addicts or alcoholics
11. Patients who cannot read the consent form (illiterates, foreigners, etc.)
12. Other patients who are judged by the principal or sub-investigator to be ineligible for participation in this clinical study