Although rare, atrioesophageal fistula is a serious and often lethal complication of radiofrequency catheter ablation in patients with atrial fibrillation (AF). Consequently, esophagogastroduodenoscopy after AF catheter ablation has been suggested to detect thermal esophageal lesions. To report the incidence of thermal lesions and other incidental gastrointestinal (GI) abnormalities in patients with AF after radiofrequency catheter ablation. Four hundred twenty-five (mean age 59 ± 10 years; 64% men) consecutive patients with symptomatic AF who underwent left atrial radiofrequency catheter ablation were scheduled for upper GI endoscopy 1-3 days after the procedure. Patients were asymptomatic for GI diseases, that is, exhibiting no dysphagia, heart burn, or abdominal pain. Pathological GI findings were observed in 328 (77%) patients and included gastral erosions (22%), esophageal erythema (21%), gastroparesis (17%), hiatal hernia (16%), reflux esophagitis (12%), thermal esophageal lesion (11%), and suspected Barrett's esophagus (5%). Biopsies were performed in 70 (17%) patients, showing gastritis (84%), Helicobacter pylori colonization (17%) and mucosa-associated lymphoid tissue (17%), esophagitis (9%), and Barrett's esophagus (4%). Further diagnostic workup or treatment was initiated in 105 (25%) patients. Upper GI pathologies are observed frequently in asymptomatic patients. Half of all patients have a requirement for treatment. Among the findings, thermal esophageal lesions and gastroparesis can be attributed to AF catheter ablation. The high incidence of gastroparesis is a novel finding that deserves further investigation.