Computed Tomogram Myocardial Thickness Map Guided pulmOnary Vein iSolaTion vs. Empirical Pulmonary Vein Isolation in Cryoballoon Ablation for Paroxysmal Atrial Fibrillation (UTMOST AF II)

New parameters or methods, such as ablation index, have been developed for the quantification of high-frequency energy used in pulmonary vein isolation, but there is no known method for atrial fibrillation considering individual differences in atrial tissue. The atrium is only 1/3 of the thickness of the ventricle and is thinner in women and older than men or young people.

The aim of this study was to evaluate the efficacy and safety of radiofrequency energy therapy using atrial individual differences. In order to reflect the thickness of the atrium, we will use the unipolar and bipolar maps and the myocardial thickness map using computed tomography (CT) images. To evaluate the efficacy and safety of energy titration therapy by random assignment of high frequency energy therapy group, CT image application high frequency energy therapy group, and existing empirical high frequency therapy group.

A. Study design

1. Prospective randomization (Unipolar voltage subtraction map guided PV(pulmonary vein) isolation group vs. CT myocardial thickness map guided PV isolation group vs. Empirical PV isolation group )
2. Target number of subjects: 480 (160 per group)
3. Rhythm FU : 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.

Eligibility Criteria:
Inclusion Criteria:

1. Patient with paroxysmal atrial fibrillation who is scheduled for ablation procedure and ≥20 and ≤80 years of age
2. Left atrium size \< 50mm
3. paroxysmal 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. Patients with persistent or permanent atrial fibrillation
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