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.