Esophageal Protective Measures
In the pre-adoption cohort, single sensor (various manufacturers) or multi-sensor LET monitoring (CIRCA Scientific, S-cath, Englewood, CO) was utilized for all patients. In all three sites, esophageal deviation (EsoSure Esophageal Retractor, Boynton Beach, FL) was also utilized in select cases. In the procedures that underwent multi-sensor LET monitoring, the probe was placed under fluoroscopic guidance and was subsequently used to monitor the temperature of the esophagus throughout the procedure. When the esophagus reached a temperature of 39°C, RF was immediately discontinued and the area was allowed to cool to the initial baseline temperature of that location as recorded on the LET monitor, or to a temperature of 36.5°C. In cases using single sensor probes, the temperature probe was repositioned as needed during the ablation to optimally position the temperature sensor opposite the RF catheter. While awaiting return to equilibrium or baseline temperature, energy was typically applied to another region of the atrium.
In the post-adoption phase, procedures utilized proactive cooling (ensoETM®, Attune Medical, IL) as a means of esophageal protection instead of LET monitoring or esophageal deviation. The ensoETM is a single-use device that consists of a closed system silicone tube that is placed into the esophagus prior to the delivery of RF energy. Distilled water circulates through the device at a rate of 2.4 L /minute and a temperature-controlled heat exchanger keeps the water at a temperature of 4°C throughout the procedure, which in turn cools the esophagus. The device has been increasingly adopted for use as a means of esophageal protection, with over 60,000 cases completed to date.11,12,14,15 In September, 2023, the device received marketing authorization from the FDA to reduce the likelihood of ablation-related esophageal injury resulting from radiofrequency cardiac ablation procedures. Due to the nature of the device, there is no temperature sensor, and thus, no need for the interruption of RF delivery due to local overheating or temperature alarms. Placement of the device is analogous to that of the standard orogastric tube which it replaces, and no repositioning is required once the device is confirmed to be in proper place by either fluoroscopy or intracardiac echocardiography. Because of the insulating effect of the layers of the fibrous pericardium, serous fluid layer, and pericardial fat, no degradation in transmurality is seen on the intended lesions placed in the left atrium.19,20