How to prevent atrial oesophageal fistula following ablation of atrial fibrillation: are there actually any effective methods?—Authors’ reply

We would like to thank Dr Giulio Zucchelli and colleagues1 for their letter regarding our recent report, which highlighted atrial oesophageal fistula (AEF), a severe complication of atrial fibrillation (AF) catheter ablation, and presenting very high-mortality rate in that population.2 Atrial oesophageal fistula is a well-known dangerous complication following AF ablation that has been recognized since pulmonary vein (PV) isolation strategy changed from ostial to antral ablation. Our report stressed that the risk for AEF still persists, despite the important technological improvement and impressive worldwide growth of PV isolation in the last years. Initially, it seemed that recognizing the problem and using simple strategies, as reducing radiofrequency (RF) power when ablating on the posterior left atrial wall, or limiting RF power based on the intra-oesophageal temperature monitoring with specific temperature probes, could prevent new cases. Unfortunately, our report demonstrated that the risk of AEF persists along the years despite several oesophageal protections attempts as we have described. Interestingly, a recent report also detected an increasing risk of AEF that was correlated to new technology introduction to obtain a more efficient PV isolation.3 The first underlined comment by our colleague was the occurrence of AEF in 8 out of 10 patients, despite monitoring the oesophageal temperature during RF delivery on the left atrium (LA) posterior wall. It is import to clarify that all the oesophageal thermometers used in the reported cases, even with multiple sensors, were mounted in a linear probe. That is a known limitation of these devices, since the temperature probe position can miss the real temperature monitoring in the contralateral oesophageal wall.4 It can explain the case #3, in which apparently the oesophagus probe was close to the right inferior pulmonary vein and the AEF occurred in the left inferior pulmonary vein. We cannot speculate the risk of patients undergoing RF catheter ablation without oesophageal temperature monitoring, since all groups involved in that report have used this strategy in their patients. In addition, all patients underwent general anaesthesia; except patient #2, who underwent PV isolation under conscious sedation. In fact, general anaesthesia seems to increase the risk of oesophageal damage; on the other hand, AEF has also been reported under conscious sedation.5 The second aspect properly pointed out by the authors was 8-mm catheters use in 3 of 10 patients undergoing AF ablation. Two cases occurred in different centres in 2003 and 2004, when this technology was the best technology to perform PV isolation. Nevertheless, the third case occurred more recently when irrigated tip technology was already currently used in all centres, except when the health system does not reimburse the irrigated tip catheters. It was the case #10, in which a box lesion was attempted. Atrial oesophageal fistula occurred despite the RF power reduction during LA posterior wall ablation and oesophageal temperature monitoring. Currently, just one of the centres still uses 8-mm tip catheters for AF ablation to attend patients of a specific health system. In this institution, the analysis of oesophageal lesions incidence on endoscopy was conducted after PV isolation and did not show any difference comparing 8-mm tip to irrigated tip catheters with contact force sensor technology. In addition, the SmartTouch (Biosense&Webster, Diamond Bar, CA, USA) catheter was the only catheter available with the contact force technology in our country in the period the AEF occurred. Power was reduced to the maximum of 20 W, pressure between 10 and 20 grams and RF delivered for 20–30 s during LA posterior wall applications. In conclusion, we thank again to the Europace editors for given us the opportunity to clarify very important points raised by our colleagues and once more to draw attention for the need of additional research to improve the safety when ablating on the LA posterior wall, independently of the technology used. Conflict of interest: none declared.