The objective of this study is to demonstrate that the NAVI-STAR THERMO-COOL catheter can be used to safely and effectively reduce symptomatic episodes of paroxysmal atrial fibrillation in patients with frequent (>3 episodes/month) or infrequent <3 episodes/month)atrial fibrillation resistant to at least one Class I or Class III antiarrhythmic drug.

The ability of a saline irrigated catheter to deliver RF energy at higher power with a lower electrode-tissue interface temperature, combined with the anatomical guidance of electroanatomical mapping should allow:

1. Isolation of the pulmonary veins at the LA-PV junction with the same or lower risk of pulmonary vein stenosis;
2. Creation of continuous, transmural linear left atrial lesions with the same or lower risk of thromboembolism;
3. These two factors will eliminate documented episodes of symptomatic sustained AF in patients with frequent (>3 episodes/month) or infrequent (<3 episodes/month);
4. Patients with interruption of the vagal response (sinus bradycardia or AV block) during stimulation at the sites of left atrial autonomic ganglionated plexi (GP) will have lower recurrence of atrial fibrillation.

Inclusion Criteria:

1. Age greater or equal to 18 years
2. At least one documented episode of atrial fibrillation (AF) within the previous 6 months.
3. Failure of at least one antiarrhythmic drug (Class I or III) defined as recurrence of AF or adverse effect.
4. Informed consent obtained.

Exclusion Criteria:

1. Left atrial thrombus
2. Acute myocardial infarction within eight (8) weeks
3. Atriotomy within eight (8) weeks
4. Decompensated heart failure (unless the AF is thought to be a significant etiologic factor and AF ablation is clinically indicated)
5. Pregnancy
6. Ablation in a pulmonary vein within 4 months.
7. Occurrence of perforation during an ablation procedure performed less than two months prior to the planned ablation date.
8. Significant congenital anomaly or medical problem that, in the opinion of the investigator, would preclude enrollment in the study.
9. Enrolled in an investigational study evaluating another device or drug
10. Unwilling to participate in the study or unavailable for follow-up visits.
11. Incarcerated

The adverse effects were collected within the 1st year after ablation.