Esophageal temperature monitoring during radiofrequency ablation of atrial fibrillation.

INTRODUCTION: Ablative strategies for atrial fibrillation have centered on the left atrium, in particular the pulmonary veins. An emphasis on ablating outside the ostia of the pulmonary veins appears to have reduced the risk of pulmonary vein stenosis. Unfortunately, ablation in the posterior left atrium has been reported to result in fatal atrio-esophageal fistula. METHODS AND
RESULTS: We monitored esophageal temperatures in 16 consecutive patients undergoing atrial fibrillation ablation. There were 14 men and 2 women; average age 54.7 +/- 10.6 years. Eight patients had a lasso-guided pulmonary isolation procedure, eight an electroanatomically guided left-atrial circumferential approach. A commercially available esophageal temperature probe (Mallinckrodt Mon-a-therm 12F Esophageal Stethoscope with Temperature Sensor, Thermistor 400 Series) was positioned under general anesthesia. Temperature changes were noted and related to the relative location of the ablation catheter and the temperature probe during the temperature change. The esophagus was midline in three, right sided in three, and left sided in the remaining patients. Temperature rises could be recorded at the posterior aspect of any pulmonary vein. Detailed analysis of six patient maps revealed heating occurred with lesions created within 1 cm of the esophagus.
CONCLUSION: The location of the esophagus relative to the back of the left atrium displays considerable variability. It is rarely midline and most often lies in close proximity to the left-sided veins. Ablation in close radiographic proximity (approximately 1 cm) to the esophagus as defined by a radio-opaque temperature probe can result in heating at the esophageal lumen.