Evaluation of the Incidence of Cerebral Lesions Post Pulmonary Vein Ablation Catheter (PVAC)

Inclusion Criteria: * Subject is at least 18 years old * Subject has been diagnosed with atrial fibrillation (AF) * Subject is indicated for a pulmonary vein ablation using PVAC * Subject (or subject's legally authorized representative) is able and and willing to give informed consent. Exclusion Criteria: * Subject has permanent AF * Subject has a left atrial thrombus detected on TEE * Subject has had a prior left atrial ablation * Subject has a intracardiac thrombus * Subject is contraindicated for Warfarin (Coumadin) * Subject has a cardiac valve prosthesis * Subject has a significant congenital heart defect corrected or not including atrial septal defects or pulmonary vein abnormalities but not including minor PFO) * Subject has presence of any pulmonary vein stents * Subject has presence of any pre-existing pulmonary vein stenosis * Subject has had a cerebral ischemic event (strokes or transient ischemic attacks \[TIA\]) which occurred during the 6 month interval preceding the Consent Date * Subject is a woman known to be pregnant * Subject is unwilling or unable to comply fully with study procedures and follow-up