Oesophageal cooling with ice water does not reduce the incidence of oesophageal lesions complicating catheter ablation of atrial fibrillation: randomized controlled study

AIM: Atrial fibrillation (AF) ablation can result in oesophageal injuries that lead to atrio-oesophageal fistulae, a life-threatening complication. This study aimed to evaluate whether oesophageal cooling could prevent oesophageal lesions complicating AF ablation. METHODS AND RESULTS: We randomly assigned 100 patients with drug-resistant AF to an oesophageal cooling group or a control group. In the oesophageal cooling group, we injected 5 mL of ice water into the oesophagus prior to radiofrequency (RF) energy delivery adjacent to the oesophagus. If the oesophageal temperature reached 42°C, the RF energy delivery was stopped, and the ice water injection was repeated. In the control group, oesophageal cooling was not applied. Oesophageal endoscopy was performed 1 day after the catheter ablation, and lesions were qualitatively assessed as mild, moderate, or severe. The numbers of ablation sites with an oesophageal temperature of >42°C were 1.7 ± 1.4 and 2.6 ± 1.7 in the oesophageal cooling group and the control group, respectively (P = 0.04), and the maximal oesophageal temperature at those sites was 43.0 ± 0.6 and 44.7 ± 0.9°C (P < 0.0001). Oesophageal lesions occurred almost equally between the oesophageal cooling group [10 of 50 patients (20%)] and the control group [11 of 50 patients (22%)]. However, the severity of the oesophageal lesions was slightly milder in the oesophageal cooling group (three moderate, seven mild) than in the control group (three severe, one moderate, seven mild). CONCLUSION: Oesophageal cooling may alleviate the severity of oesophageal lesions but does not reduce the incidence of this complication under the specific protocol evaluated here.