Sensitivity and accuracy of Sensitherm/Esotherm oesophageal temperature probe: reply

We would like to thank Antonio Fasano for his letter1 and interest in our research.2 Our centre, as many other centres in the world, does not use a luminal oesophageal temperature (LET) probe regularly to guide atrial fibrillation (AF) ablation. This is why the study was designed as an observational one planned to collect data from two different LET probes but without using them to guide the procedure. The study was funded by a competitive grant from the Spanish Society of Cardiology. Additional safety measures to that commonly used included RF delivery limited to a maximum of 30 W for 30 s per site and oesophageal endoscopy performed the day after the procedure in all patients. Patients were followed with a special diet, proton-pump inhibitors, and repeated endoscopies if oesophageal lesions were detected. This was the case in 28% of them, which is similar to what has been reported by others.3 No patient developed oesophageal complications at follow-up. These latter data are being analysed for subsequent publication and we would like not to disclose them in detail yet but at least we can say that the sensitivity and specificity of the maximum LET detected by the conventional oesophageal probe to predict oesophageal lesions were <50%. These were higher but still relatively low for the steerable oesophageal probe, raising the question whether LET is the main factor for oesophageal complications or others may play a more important role. It is well established that dramatic tissue temperature differences (5–20°C) are commonly found during RF delivery in sites separated by just 3 mm.4,5 The oesophagus is a wide structure (maximal luminal diameter between 19 and 29 mm) which often contains remains of fluid and air.6 Therefore, it appears unlikely that the temperature at one site on the luminal aspect of the oesophageal wall will reflect accurately that one of another distant site on the opposite wall even if the temperature detector is not subject to interference by surrounding air and liquid. This may explain some reports of atrio-oesophageal fistula development despite LET monitoring during the AF ablation procedure.3,7 Finally, research and clinical trials may impose risks to patients. However, accepting methods and tools without fully understanding them by additional research may give a false impression of safety, which may also expose patients to risks. Manufacturing companies have the legal and ethical responsibility of looking for and into new data about their products thoroughly and objectively. In this regard, we all should maintain an open mind to new ideas and not be satisfied just by questioning the scientific and moral integrity of those who raise them. This is especially important if these ideas pertain to patient safety and/or have potential conflicts with our own interest. The history of science has taught us repeatedly that some of our most established principles were wrong. Therefore, we should try to avoid or at least minimize the process described by Arthur Schopenhauer more than 150 years ago ‘All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.’ Conflict of interest: none declared.