Enrolled subjects will be treated with the Synaptic Cryoablation System. Treatment will include cryoablation of the pulmonary veins to achieve PVI. All subjects will be followed for twelve (12) months after completion of the index ablation procedure.

A multi-center, open-label, prospective, single-arm, pre-market clinical study. Enrolled subjects will be treated with the Synaptic Cryoablation System. Treatment will include cryoablation of the pulmonary veins to achieve PVI. All subjects will be followed for twelve (12) months after completion of the index ablation procedure. Data will be collected at enrollment, procedure, discharge, 1, 3, 6 and 12- months to assess the safety and effectiveness of the System. Testing for recurrence of atrial fibrillation will include a 12-lead ECG at 1, 3, 6 and 12-months post-ablation, weekly event recorder transmissions (TTM) after the 3-month follow-up visit through the 12-month follow up, and a 24-h continuous Holter ECG recording at 6 and 12-months post ablation. Symptom triggered rhythm monitoring will be used throughout the effectiveness post-ablation period.

Inclusion Criteria:

• Diagnosis of symptomatic Paroxysmal Atrial Fibrillation (PAF), defined as atrial fibrillation that terminates spontaneously or with intervention (either through procedure or drug therapy) within seven (7) days of onset. Minimum documentation includes the following:

  1. A physician's note indicating recurrent atrial fibrillation (AF) which includes at least two (2) symptomatic AF episodes within six (6) months prior to enrollment; AND
  2. One electrocardiographically (from any form of rhythm monitoring, including consumer devices) documented AF episode within 12 months prior to enrollment.

• Refractory or intolerant to at least one (1) Class I or III anti-arrhythmic medication or contraindicated to any class I or III medication.

• Suitable candidate for catheter ablation.

• Adults aged 18 - 80 years.

• Willing and able to comply with all baseline and follow-up evaluations for the full length of the study.

• Willing and able to provide informed consent.

Exclusion Criteria:

• Diagnosis of persistent AF, i.e., continuous AF lasting longer than seven (7) days from onset

• In the opinion of the Investigator, any known contraindication to an atrial ablation or anticoagulation. Including but not limited to the identification of any atrial thrombus or evidence of sepsis

• History of previous left atrial ablation or surgical treatment for AF/AFL/AT

• Atrial fibrillation secondary to electrolyte imbalance, thyroid disease, or any other reversible or non-cardiac cause

• Body Mass Index (BMI) ≥ 40

• Structural heart disease or implanted devices as described below:

  1. Left ventricular ejection fraction (LVEF) < 40% based on most recent transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE) performed ≤ 180 days prior to enrollment
  2. Left atrial diameter > 5.5 cm or left atrial volume > 50 ml/m2 indexed based on most recent TTE or TEE performed ≤ 180 days prior to enrollment
  3. Implanted pacemaker, ICD, CRT device within 90 days prior to enrollment
  4. Previous cardiac surgery, ventriculotomy, or atriotomy (excluding atriotomy for CABG)
  5. Previous cardiac valvular surgical or percutaneous procedure, or prosthetic valve, including mitral valve clips
  6. Interatrial baffle, closure device, patch, or patent foramen ovale (PFO) occluder
  7. Presence of a left atrial appendage occlusion device
  8. Presence of any pulmonary vein stents
  9. Coronary artery bypass graft (CABG), PTCA, PCI, or coronary stent procedures within 90 days prior to enrollment
  10. Unstable angina or ongoing myocardial ischemia
  11. ST-Elevation Myocardial Infarction (STEMI) within 90 days prior to enrollment
  12. Moderate or Severe Mitral Insufficiency or Mitral Stenosis, severity based on the most recent TTE or TEE performed ≤ 180 days prior to enrollment
  13. Evidence of left atrial thrombus

• History of cryoglobulinemia

• Significant untreated restrictive or obstructive pulmonary disease or chronic respiratory condition

• Renal failure requiring dialysis

• History of blood clotting or bleeding disease

• History of documented cerebral infarct, TIA or systemic embolism,excluding post-operative deep vein thrombosis (DVT) ≤ 180 days prior to enrollment

• Active systemic infection

• Pregnant or lactating (current or anticipated during the study)

• Current enrollment in any other study protocol where testing or results from that study may interfere with the procedure or outcome measurements for this study

• Any other condition that, in the judgment of the Investigator, makes the patient a poor candidate for this procedure, the study or compliance with the protocol (includes, but not limited to, vulnerable patient population, mental illness, Gastroesophageal Reflux Disease (GERD), addictive disease, terminal illness with a life expectancy of less than two (2) years, or extensive travel away from the research center)