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 studyprocedures which includes surgical AF ablation and completing follow-up visits asspecified in the clinical study protocol

• Subject has history of documented atrial fibrillation within one year prior toenrollment. Documentation may include ECG, transtelephonic monitor (TTM), holtermonitor or telemetry strip

• Subject is scheduled to undergo non-emergent cardiac surgical procedure(s) to beperformed on cardiopulmonary bypass including open-heart surgery for one or more ofthe following: Mitral valve repair or replacement, Aortic valve repair orreplacement, Ascending aortic aneurysms, or Coronary artery bypass procedures

• Left ventricular ejection fraction ≥ 30% (determined by echocardiography or cardiaccatheterization performed within 60 days of enrollment as documented in patientmedical 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/oratrial 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 ifthere is residual neurological deficit

• Documented ST-segment elevation Myocardial Infarction (MI) within the 6 weeks priorto 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 minimalexertion

• 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 understandthe 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 includingintermittent 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 KAntagonists such as warfarin)

• Solid organ or hematologic transplant, or currently being evaluated for an organtransplant

• Body mass index > 40 kg/m2

• Use of any other investigational drug, therapy, or device within 30 days prior toenrollment or concurrent participation in another research study