Standard of Care
Currently, the standard of care is to place a temperature probe in the esophagus to provide luminal esophageal temperature (LET) monitoring. Studies have shown that ablation energy delivered within the left atrium near the esophagus significantly increase the LET23-27. Esophageal lesions have been shown to correlate with LET exceeding 41° C16,18. However, LET monitoring has several limitations26,27. Often times, the LET is surrounded by air, which acts as an insulator and reduces prompt transmission of temperature change to the LET probe. In part, this explains why an increase in LET is associated with latency (the measured temperature rise lags behind the actual peak temperature), inaccuracy, and underestimation of the esophagus temperature at the outer layers closer to the ablation source (adventitia, muscularis, and submucosa, which is the site of esophageal blood supply). In addition, rises in LET mandate interruption in energy delivery that interrupt workflow and potentially decrease procedural efficacy; and, most troublesome, esophageal injury/fistulas have been reported even with careful LET monitoring demonstrating no temperature rise1,15,23. Thus LET monitoring is an inadequate method to guide ablation therapy to avoid esophageal injury.