Safe and effective ablation of atrial fibrillation: importance of esophageal temperature monitoring to avoid periesophageal nerve injury as a complication of pulmonary vein isolation.

INTRODUCTION: Catheter ablation on the left atrial posterior wall has been reported to potentially damage the esophagus or periesophageal vagal nerve. The aim of this study was to evaluate the efficacy of esophageal temperature monitoring (ETM) in preventing esophageal or periesophageal vagal nerve injury in patients with atrial fibrillation (AF) undergoing pulmonary vein (PV) isolation.
METHODS: This study included 359 patients with drug-refractory AF who underwent extensive PV isolation. The first 152 patients were treated without ETM (non-ETM) and the last 207 with ETM. In the ETM group, the esophageal temperature (ET) was measured with a deflectable temperature probe that was placed close to the ablation electrode, and the radiofrequency energy applications were stopped when the ET reached 42 degrees C.
RESULTS: In all patients in the ETM group, the ET increased to 42 degrees C in at least one site by 28 +/- 14 seconds, mostly along the right side of the left PVs, especially near the left inferior PV. Less energy (6.3 +/- 1.9 x 10(4) J) was required for PV isolation in the ETM group than that in the non-ETM (6.8 +/- 1.9 x10(4) J, P = 0.03). Gastric hypomotility owing to periesophageal nerve damage was observed in three patients in the non-ETM group, but in none in the ETM (P = 0.02). The recurrence rates of AF did not differ between the two groups (non-ETM, 29%; ETM, 27%).
CONCLUSION: Titration of the duration of the ablation energy delivery while monitoring the ET could prevent periesophageal nerve injury due to the AF ablation, without decreasing the success rate of maintaining sinus rhythm.