Abstract 2548: Intraesophageal Temperature Monitoring During Radiofrequency Catheter Ablation of Atrial Fibrillation: Does it Predict Esophageal Injury?
Background. Atrioesophageal fistula formation is a rare, but often lethal complication of radiofrequency (RF) ablation of atrial fibrillation (AF) resulting from thermal injury to the esophagus during ablation of the left atrial (LA) posterior wall. The aim of this study was to evaluate the relationship (1) between the course of the esophagus and the sites of RF energy delivery associated with an increase in intraesophageal temperature (IET) measured by an intraluminal temperature probe and (2) between the incidence of mucosal damage as evidenced by esophageal endoscopy (EES) and IET.
Methods. One hundred fifty-three patients (pts) with symptomatic, drug-refractory AF (mean age 58±10 years, 42% female, 46% paroxysmal AF, 33% lown AF) underwent circumferential pulmonary vein (PV) ablation plus placement of additional linear ablation lines in case of persistent AF. A multi-sensor esophageal temperature probe was used for real-time IET monitoring. The course of the esophagus was determined by the position of the probe visualized on the NAVX Ensite system. RF applications were interrupted until IET returned to baseline values when IET exceeded 40°C. Ablation was subsequently continued with lower RF energy and irrigation flow (IF). EES was performed 1 to 4 days after the procedure.
Results. RF energy and/or IF had to be reduced in 136 pts (89%) from the initial setting (40 W, flow are 30 ml/h) to 25±9 W and 24±5 ml/h, respectively. In 114 of these pts (84%), IET only increased when ablation lines were placed in close vicinity to the esophagus. On the contrary, a rise in IET was observed in 22 pts (16%) when ablation was performed in LA areas remote from the esophagus. Mucosal damage was observed on EES in 3 out of 16 pts (19%), in 11 out of 27 pts (41%), and in 5 out of 31 pts (16%) in whom maximum IET reached levels of greater than or equal to 44°C, 43°C, and 42°C, respectively. However, in 79 pts (52%) no mucosal injury occurred when maximum IET was less than or equal to 41°C.
Conclusion. Increases in IET mainly occur when ablation is performed in close proximity to the esophagus. The extend of mucosal injury is strongly related to IET. Using a cut-off value of 41°C to drive postprocedural EES might help to identify pts at a higher risk for esophageal complications after RF catheter ablation of AF.