The development of an atrio-oesophageal fistula following catheter ablation for atrial fibrillation is a well known, but rare complication with a high mortality, partially due to the late fistula formation weeks after the initial procedure. Technical measurements are undertaken to avoid oesophageal damage during catheter ablation of atrial fibrillation, yet, oesophageal and mediastinal lesions occur in a substantial number of patients following pulmonary vein isolation. This has led to prophylactic use of proton pump inhibitors in many centres. Current guidelines and consensus reports list no objectives on this issue. The aim of the paper is therefore to review current clinical and experimental evidence for this treatment.