This is a multi-center sub-study examining the effectiveness of active esophageal cooling on subjects undergoing left atrial ablation for symptomatic Paroxysmal Atrial Fibrillation or Persistent Atrial Fibrillation.

Treatment of atrial fibrillation, using pulmonary vein isolation, involves some risks to collateral structure, including the esophagus. Active esophageal cooling has shown benefits in multiple studies when used in the treatment of Paroxysmal Atrial Fibrillation or Persistent Atrial Fibrillation during left atrial ablation. The largest randomized, controlled trial to date, the IMPACT study, found an 83% reduction in endoscopically identified esophageal lesions when using the active cooling, with a dedicated device, compared to standard esophageal monitoring, with no difference in Atrial Fibrillation recurrence rates at follow-up. Recent analyses have suggested additional effects from active esophageal cooling during pulmonary vein isolation, including reductions in procedure time, reductions in fluoroscopy usage, reductions in post-ablation discomfort, and improvements in long-term freedom from arrhythmia. Further investigation of these associations is important to better understand the magnitude of these findings in a variety of clinical settings.

Inclusion Criteria:

• Symptomatic Paroxysmal Atrial Fibrillation (AF episode terminate spontaneously within 7 days) or Persistent Atrial Fibrillation (AF sustained beyond 7 days) who, in the opinion of the investigator, are scheduled for ablation for Atrial Fibrillation with active esophageal cooling.
• >18 years of age
• Index or redo ablation procedure and enrolled in the REAL AF Registry
• Willing and able to provide informed consent and complete GERD questionnaire.

Exclusion Criteria:

• For the purpose of this sub-study, candidates will be excluded if they meet any of the following criteria:
• Enrolled in an investigational drug or device clinical trial, or any trial that dictates the treatment plan.
• In the opinion of the investigator, any known contraindication to an ablation procedure.
• <18 years of age

The sub-study will consist of consecutive male and female patients enrolled in the REAL AF Registry who have symptomatic Paroxysmal Atrial Fibrillation (PAF) or Persistent Atrial Fibrillation (PsAF) and undergo left atrial ablation for the treatment of atrial fibrillation.