CellFX® nsPFA™ Cardiac Surgery System to Treat Atrial Fibrillation

Inclusion Criteria: * Subject must be between 18 and 85 years of age * Subject is willing and capable of providing Informed Consent to undergo study procedures which includes surgical AF ablation and completing follow-up visits as specified in the clinical study protocol * Subject has history of documented atrial fibrillation within one year prior to enrollment. Documentation may include ECG, transtelephonic monitor (TTM), holter monitor or telemetry strip * Subject is scheduled to undergo non-emergent cardiac surgical procedure(s) to be performed on cardiopulmonary bypass including open-heart surgery for one or more of the following: Mitral valve repair or replacement, Aortic valve repair or replacement, Ascending aortic aneurysms, or Coronary artery bypass procedures * Left ventricular ejection fraction ≥ 30% (determined by echocardiography or cardiac catheterization performed within 60 days of enrollment as documented in patient medical history) * Subject has a life expectancy of at least 5 years Exclusion Criteria: * Subject has an implantable electronic medical device. (i.e., pacemaker, ICD or CRT) or left atrial appendage device * Subject has a prosthetic heart valve * Stand-alone AF without indication(s) for concomitant Coronary Artery Bypass Graft (CABG) and/or valve surgery * Previous surgical Maze procedure * Prior cardiac surgery (Redo) * Wolff-Parkinson-White syndrome or other Supra-Ventricular arrhythmia, Atrioventricular (AV) nodal reentry * Subjects requiring surgery other than CABG and/or cardiac valve surgery and/or atrial septal defect repair. * Prior history of medical procedure involving instrumentation of the left atrium (e.g., previous ablation) * Class IV New York Heart Association (NYHA) heart failure symptoms * Prior history of cerebrovascular accident or TIA within 6 months or at any time if there is residual neurological deficit * Documented ST-segment elevation Myocardial Infarction (MI) within the 6 weeks prior to study enrollment * Need for emergent cardiac surgery (i.e., cardiogenic shock) * Known carotid artery stenosis greater than 80% * Current diagnosis of active systemic infection * Severe peripheral arterial occlusive disease defined as claudication with minimal exertion * Renal failure requiring dialysis or hepatic failure * A known drug and/or alcohol addiction * Mental impairment or other conditions which may not allow the subject to understand the nature, significance and scope of the study * Pregnancy or desire to get pregnant within 12-months of the study treatment * Preoperative need for an intra-aortic balloon pump or intravenous inotropes * Subjects who have been treated with thoracic radiation * Subjects in current chemotherapy * Subjects on long term treatment with oral or injected steroids (not including intermittent use of inhaled steroids for respiratory diseases) * Subjects with known hypertrophic obstructive cardiomyopathy * Subjects with known cold agglutinin * History of abnormal bleeding and/or clotting disorder * Contraindication to anticoagulation (i.e., Heparin, Dabigatran, Apixaban, Vitamin K Antagonists such as warfarin) * Solid organ or hematologic transplant, or currently being evaluated for an organ transplant * Body mass index \> 40 kg/m2 * Use of any other investigational drug, therapy, or device within 30 days prior to enrollment or concurrent participation in another research study