The purpose of this randomized clinical trial is to compare the efficacy and safety of wide area circumferential ablation using contact force catheter with cryoballoon ablation for the treatment of paroxysmal atrial fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with stroke, reductions in quality of life and overall survival. Previous studies have shown that cryoballoon ablation was noninferior to radiofrequency ablation with respect to efficacy for the treatment of patients with drug-refractory paroxysmal atrial fibrillation. However, the pulmonary vein isolation for radiofrequency catheter ablation in previous studies was done around each pulmonary-vein antrum, and it's not wide area circumferential ablation. Moreover, the induction of atrial fibrillation by isoproterenol or programmed stimulation and burst pacing was not performed in most of previous studies. We hypothesize that wide area circumferential ablation with contact force catheter and combined catheter ablation the potential atrial triggers and/or other atrial arrhythmias induced by aggressive induction is more effective than cryoballoon ablation in patients with paroxysmal atrial fibrillation.

Inclusion Criteria:

1. Symptomatic PAF with at least two episodes and at least one episode documented (30 seconds episode length, documented by ECG within last 12 months).

   Documented treatment failure for effectiveness of at least one anti-arrhythmic drug(AAD Type I or III, including β-blocker and AAD intolerance).

2. ≥ 18 and ≤ 75 years of age.

3. Patients who are mentally and linguistically able to understand the aim of the trial and to show sufficient compliance in following the trial protocol.

4. Patient is able to verbally acknowledge and understand the associated risks, benefits, and treatment alternatives to therapeutic options of this trial: cryoballoon ablation system or standard RF ablation technique. The patients, by providing informed consent, agree to these risks and benefits as stated in the patient informed consent document. All the details have been presented to him and he has signed the informed consent form for the trial.

Exclusion Criteria:

Exclusion criteria related to a cardiac condition

1. Patients with prosthetic valves.
2. Any previous LA ablation or surgery.
3. Any cardiac surgery or percutaneous coronary intervention (PCI) within three months prior to enrollment.
4. Unstable angina pectoris.
5. Myocardial infarction within three months prior to enrollment.
6. Symptomatic carotid stenosis.
7. Chronic obstructive pulmonary disease with detected pulmonary hypertension.
8. Any condition contraindicating chronic anticoagulation.
9. Stroke or transient ischemic attack within six months prior to enrollment.
10. Any significant congenital heart defect corrected or not (including atrial septal defects or PV abnormalities) but not including patent foramen ovale.
11. New York Heart Association (NYHA) class III or IV congestive heart failure.
12. EF < 35 % (determined by echocardiography within 60 days of enrollment as documented in patient medical history).
13. Anteroposterior LA diameter > 55 mm (by trans-thoracic echocardiography (TTE or TEE) within three months to prior enrollment).
14. LA thrombus (TEE diagnostic performed on admission). Intracardiac thrombus.
15. PV diameter > 26 mm in right sided PVs.
16. Mitral prosthesis.
17. Hypertrophic cardiomyopathy
18. 2° (Type II) or 3° atrioventricular block.
19. Brugada syndrome or long QT syndrome.
20. Arrhythmogenic right ventricular dysplasia.
21. Sarcoidosis.
22. PV stent.
23. Myxoma.

Exclusion criteria based on laboratory abnormalities

1. Thrombocytosis (platelet count > 600,000 / µl), thrombocytopenia (platelet count < 100,000 / µl).
2. Any untreated or uncontrolled hyperthyroidism or hypothyroidism.
3. Severe renal dysfunction (stage V, requiring or almost requiring dialysis, glomerular filtration rate (GFR) < 15 ml / min).