Association between the sedation type and the risk of major oesophageal injury following increased intraoesophageal temperature during radiofrequency ablation for the treatment of atrial fibrillation.

Background: Catheter ablation (CA) has become the leading treatment option for patients with atrial fibrillation (AF). However, the use of thermal energy is still associated with the risk of specific complications, including atrio-oesophageal fistula (AEF). Several methods have been described to reduce the risk of AEF, such as adjusting the energy of a single application to limit oesophageal temperature (OT). Some authors have indicated the need for routine oesophageal monitoring if peri-procedural OT increased. Given the still limited knowledge on this topic, we assessed the frequency and nature of oesophageal lesions, including those of an ulcerative nature, in patients in whom a peri-procedural OT increase to above 41 ℃ was detected. We also searched for factors correlated with the risk of deep oesophageal injury, which are associated with a higher risk of AEF. The extent of oesophageal damage was analysed according to the Kansas City Classification depending on the type of anaesthesia. Methods: We retrospectively analysed single-centre data of patients who underwent a radiofrequency (RF) ablation of AF using a "point-by-point" approach between 2013 and 2023. If the OT rose to above 41 ℃, we routinely screened the patients in-hospital for endoscopic abnormalities in the oesophagus. We analysed baseline patient characteristics, anatomical parameters, peri-procedural data, including the type of anaesthesia used, and post-procedural endoscopic findings in the oesophagus. Results: The final analysis included 121 patients, mainly male subjects with paroxysmal AF primarily affected by hypertension. Most patients had preserved left ventricular systolic function and a slightly enlarged left atrium (LA). A "C"-type course of the oesophagus in relation to LA was predominant. Most patients underwent ablation under general anaesthesia (GA). The median of maximum OT recorded during application was 41.5 ℃. On endoscopy, features of thermal damage to the oesophagus were found in most patients-predominant erythema and mucosal oedema (60%). Superficial or deep ulcerations was found in 16 patients. In the multivariate analysis, higher body weight decreased the risk of injury, while deep sedation significantly increased the risk. Conclusions: In a single-centre experience, an increase in OT above 41 ℃ during AF ablation using RF energy is associated with a high risk of oesophageal thermal injury of varying severity. Additionally, periprocedural deep sedation may further increase the extent of such injury.