Limitations of Esophageal Temperature-Monitoring to Prevent Esophageal Injury During Atrial Fibrillation Ablation

A number of complications have been associated with ablation of atrial fibrillation (AF), including arterial thrombo-embolism, pulmonary vein stenosis, phrenic nerve injury, and pericardial tamponade.1–4 Esophageal injury, manifested as esophageal perforation or left atrial-esophageal fistula, has been reported after catheter or surgical ablation of AF using radiofrequency (RF) current5–8 and catheter ablation using high-intensity focused ultrasound (HIFU).9 Left atrial-esophageal fistula usually is associated with a very high morbidity and mortality, including air embolism and sepsis. Article see p 162 Esophageal injury during RF ablation in the left atrium is thought to be thermal injury.10–12 In this issue of Circulation: Arrhythmia and Electrophysiology , Singh et al13 sought to determine whether the risk of esophageal injury would be reduced by measuring the luminal esophageal temperature (LET) during ablation and maintaining the LET below 38.5°C. The LET was measured using a 9Fr flexible temperature probe (with a single thermocouple) in the esophagus. The temperature probe was maneuvered in cranial-caudal direction to position the thermocouple close to the ablation catheter tip in the left atrium. We agree in principal with the authors’ conclusion that esophageal temperature-monitoring may reduce the risk of esophageal injury during AF ablation. An esophageal ulcer was observed by endoscopy 1 to 3 days postablation in 4 of 67 (6%) patients with LET-monitoring (and discontinuing RF application at LET ≥38.5°C) compared to 5 of 14 (36%) patients without LET-monitoring. Importantly, in patients with LET-monitoring, this study showed no significant difference between patients with and without an esophageal ulcer and the maximum LET during ablation or the number of RF applications producing an increase in LET to ≥38.5°C. …