NAVISTAR® THERMOCOOL® Catheter for the Radiofrequency Ablation of Symptomatic Paroxysmal Atrial Fibrillation (Afib IDE)

You may be eligible to participate in this study if you: Have failed to respond to drug treatment for your AFib, or find the side effects of your medication intolerable. Inclusion Criteria Patients with symptomatic PAF who have had three (3) AF episodes in the six (6) months prior to randomization, one of which must be documented. Documentation may include electrocardiogram (ECG), transtelephonic monitor (TTM), Holter monitor (HM), or telemetry strip. Failure of at least one AAD for PAF [class I or III or AV nodal blocking agents such as beta blockers (BB) and calcium channel blockers (CCB)] as evidenced by recurrent symptomatic PAF, or intolerable side effects due to AAD. Signed Patient Informed Consent Form. Age 18 years or older. Able and willing to comply with all pre-, post- and follow-up testing and requirements. Exclusion Criteria Atrial fibrillation secondary to electrolyte imbalance, thyroid disease, or reversible or non-cardiac cause. Previous ablation for atrial fibrillation. Patients on amiodarone therapy at any time during the previous six (6) months. AF episodes that last longer than 30 days and are terminated via cardioversion. Any valvular cardiac surgical procedure. CABG procedure within the last 180 days (six months). Awaiting cardiac transplantation or other cardiac surgery within the next 360 days (12 months). Documented left atrial thrombus on imaging (e.g. TEE). History of a documented thromboembolic event within the past one (1) year. Diagnosed atrial myxoma. Presence of implanted ICD. Significant pulmonary disease, (e.g. restrictive pulmonary disease, constrictive or chronic obstructive pulmonary disease) or any other disease or malfunction of the lungs or respiratory system that produces chronic symptoms. Significant congenital anomaly or medical problem that in the opinion of the investigator would preclude enrollment in this study. Women who are pregnant (by history of menstrual period or pregnancy test if the history is considered unreliable). Acute illness or active systemic infection or sepsis. Unstable angina. Myocardial infarction within the previous 60 days (two months). LVEF < 40%. History of blood clotting or bleeding abnormalities. Contraindication to anticoagulation (i.e. heparin or warfarin). Contraindication to CT/MRA procedure. Life expectancy less than 360 days (12 months). Enrollment in an investigational study evaluating another device or drug. Uncontrolled heart failure or NYHA class III or IV heart failure. Presence of intramural thrombus, tumor or other abnormality that precludes catheter introduction or manipulation. Presence of a condition that precludes vascular access. Left atrial size ≥ 50 mm