The purpose of this study is to prospectively follow the next 200 patients who undergo catheter ablation of atrial fibrillation for symptoms and signs of esophageal injury.

The purpose of this study is to prospectively follow the next 200 patients who undergo catheter ablation of atrial fibrillation and endoscopy. If any signs of esophageal injury are seen on endoscopy the patients will be treated with omeprazole and sucralfate and they will have repeat endoscopy in two weeks. Patients who do not have any esophageal injury will be contacted by telephone in two weeks to be assessed for GI symptoms.

Specific Aims: The specific aims of the study are to:

1. Assess the incidence of visible transmural esophageal injury following extensive ablation in the posterior left atrium as measured by endoscopy1
2. Assess whether early detection of esophageal injury by endoscopy and treatment will prevent development of more serious injury such as left atrial-esophageal fistula
3. Identify predictors of esophageal injury. In particular, to assess if esophageal temperature rises during ablation correlate with development of esophageal injury and if the absence of esophageal temperature rise during ablation correlate with the absence of esophageal injury.

Inclusion Criteria:

• 18-80 years
• Scheduled to have catheter ablation of atrial fibrillation or left atrial macroreentrant tachycardia.

Exclusion Criteria:

• Contraindication to endoscopy
• Pregnancy
• Prisoners
• Inability or unwillingness to give informed consent

Patients 18-80 scheduled to undergo catheter ablation of atrial fibrillation

Endoscopy one day after ablation Clinical evaluation 1 month after ablation

Adverse events were collected by:

1. endoscopy results
2. Telephone survey at one month