The objective of this study is to demonstrate initial safety and effectiveness of the CellFX nano-second Pulsed Field Ablation (nsPFA or nano-PFA) 360 Catheter Endocardial Ablation System in treating subjects with atrial fibrillation.

This study is a prospective, non-randomized, open labelled, single-arm first-in-human (FIH) feasibility study to evaluate the initial clinical safety and device performance of the nano-PFA 360 Catheter Endocardial Ablation System for the treatment of atrial fibrillation. Enrolled subjects will be followed for up to 12 months post-nano PFA 360 Catheter Ablation. All subjects will undergo an electroanatomical mapping procedure post-ablation to evaluate immediate pulmonary vein isolation (PVI) and at 3 months post-index procedure to assess electrical isolation of the pulmonary veins.

Inclusion Criteria:

• Subject must be ≥ 18 and ≤ 75 years of age on the day of enrollment
• Subject is willing and capable of providing Informed Consent to undergo study procedures and participate in all examinations and follow-up visits and tests associated with this clinical study
• Subjects with PAF who have had at least one AF episode documented within one (1) year prior to enrollment. Documentation may include ECG, transtelephonic monitor (TTM), Holter monitor (HM), or telemetry strip
• Subjects who have failed at least one antiarrhythmic drug (AAD; class I or III, or AV nodal blocking agents such as beta blockers and calcium channel blockers) as shown by recurrent symptomatic AF, or intolerance to the AAD or AV nodal blocking agents
• Antero-posterior left atrial diameter ≤ 5.5 cm as documented by transthoracic echocardiography (TTE) or computed tomography (CT) within 3 months prior to the procedure
• Left ventricular ejection fraction ≥ 40% as documented by TTE within 12 months prior to the procedure
• Received a standard cardiac work up and is an appropriate candidate for an investigational procedure as determined by the study investigators

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

• AF secondary to electrolyte imbalance, thyroid disease, or reversible or non-cardiac cause

• AF episodes lasting > 7 days

• Previous ablation for AF

• Subjects on amiodarone at any time during the past 3 months prior to enrollment

• Prior history of pericarditis or pericarditis within 3 months based on the TTE examination

• Prior history of rheumatic fever

• Prior history of medical procedure involving instrumentation of the left atrium (previous ablation, atrial septal defect (ASD) closure, left atrial appendage occlusion)

• History of severe chronic gastrointestinal problems involving the esophagus, stomach and/or untreated acid reflux

• History of abnormal bleeding and/or clotting disorder

• Contraindication to anticoagulation (i.e., Heparin, Dabigatran, Apixaban, Vitamin K Antagonists such as Warfarin)

• Active malignancy or history of treated cancer within 24 months of enrollment

• Clinically significant infection or sepsis on the day of index procedure with either fever, leukocytosis or requiring intravenous antibiotics

• History of stroke or TIA within prior 6 months, or any prior intracranial hemorrhage or permanent neurological deficit

• New York Heart Association (NYHA) class IIIb or IV congestive heart failure and/or any heart failure hospitalization within 3 months prior to enrollment

• Body mass index > 35 kg/m2

• Estimate glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 or has ever received hemodialysis

• History of untreated and serious hypotension, bradycardia or chronotropic incompetence

• Any of the following within 3 months of enrollment:

  1. Major surgery except for the index procedure
  2. Myocardial infarction
  3. Unstable angina
  4. Percutaneous coronary intervention
  5. Sudden cardiac death event
  6. Left atrial thrombus that has not resolved as shown by TEE or CT

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

• History of pulmonary hypertension with pulmonary systolic artery pressure >50 mm Hg, severe Chronic Obstructive Pulmonary Disease or restrictive lung disease

• Subjects with any other significant uncontrolled or unstable medical condition (such as uncontrolled brady-arrhythmias, ventricular arrhythmias, hyperthyroidism or significant coagulation disorder)

• Life expectancy less than one year

• Clinically significant psychological condition that in the physician's opinion would prohibit the subject's ability to meet the protocol requirements.

• Females of childbearing potential who are nursing, pregnant, or planning to become pregnant during the study period

• Other criteria, which the Investigator determines would make the patient unsuitable to participate (e.g. uncontrolled drug and/or alcohol addiction, congenital disease, fragility)