Abstract 2103: Open Irrigation Catheters Generate Higher Esophageal Tissue Temperatures than Standard 8mm Tip Catheters when Ablating within the Left Atrium
Introduction: Atrial-esophageal fistula is a devastating potential complication of catheter ablation of atrial fibrillation that is thought to be caused by thermal injury. Both open irrigation catheters (OIC) and large 8mm tip catheters (8mm) are used for this procedure.
Objective: To compare the thermal affects on the esophagus (Eso) of the 3.5mm OIC with that of the 8mm during radiofrequency (RF) ablation of the left atrium (LA).
Methods: Via lateral thoracotomy, 6 dogs underwent placement of a tissue thermocouple onto the anterior surface of the Eso immediately posterior to the LA. An intra-luminal Eso temperature probe was advanced to the level of the LA and tissue thermocouple. Under intracardiac echocardiographic guidance an ablation catheter was advanced into the LA via transseptal puncture. RF lesions were applied to the LA posterior wall near the Eso. In 3 dogs an 8mm delivered lesions at a setting of 50W, 60°C for 90 seconds. In 3 dogs an OIC delivered lesions near the Eso with a setting of 50W, 45°C, 30cc/min flow rate for 90 sec. Simultaneous temperature recordings were obtained from the catheter, tissue thermocouple, and luminal Eso temperature probe.
RESULTS: An average of 12.6±5 RF lesions were placed in each dog. Anterior Eso tissue temperature significantly increased during each RF application with both the OIC (38.4±0.5°C to 90.7±21.4 °C, p<0.01) and 8mm (38.3±0.5°C to 58.7±7.6 °C, p < 0.01). There was also a significant increase in luminal Eso temperature during RF application with both the OIC (37.3±0.42°C to 40.6±1.2 °C, p< 0.01) and the 8mm (37.2±0.1°C to 39.5±0.6 °C, p < 0.01). The mean increase in anterior Eso tissue temperature was greater with OIC compared to 8mm (52.3±21.6°C vs 20.4±7.9°C, p=0.01). Interestingly, this was not observed with the luminal Eso temperature when comparing lesions from the OIC and the 8mm (3.3±1.2°C to 2.3±.7 °C, p=NS).
CONCLUSION: Lesions delivered with OIC appear to increase Eso tissue temperature more than the standard 8mm. This difference is not reflected in intra-luminal Eso temperature measurements.