Repeatable Evaluation of Functional Intra-procedural Signals for Effect in Pulsed Field Ablation REFINE-PFA

Inclusion Criteria: Eligible subjects will meet all of the following inclusion criteria: 1. Subjects undergoing first time pulmonary vein isolation indicated by investigator for the treatment of atrial fibrillation. 2. Male or non-pregnant female aged ≥21 years. 3. Able and willing to provide written informed consent prior to any clinical investigation related procedure. 4. Subjects in sinus rhythm at the time of the PFA application. Exclusion Criteria: Eligible subjects will not meet any of the following exclusion criteria: 1. Pregnant or nursing subjects. 2. Current participation in another investigational drug or device study that interferes with this study. 3. Subjects who, in the opinion of the investigator, are not candidates for this study. 4. Patients who have had a prior ablation procedure. 5. Presence of other anatomic or comorbid conditions, or other medical, social, or psychological conditions that, in the investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with follow-up requirements, or impact the scientific soundness of the clinical investigation results. 6. Life expectancy is less than 12 months, in the opinion of the investigator. 7. Subjects who, in the opinion of the investigator, are considered part of any vulnerable population. 8. Subjects unlikely to be in sinus rhythm at the time of the procedure or unlikely to remain in sinus rhythm after cardioversion