The Esophageal Temperature Probe: Helpful Monitoring Device or Inadvertent Amplifier of Risk?

Abstract

Editorial CommentCatheter ablation targeting the pulmonary veins or left atrial substrate, or both, has become an established strategy for the management of patients with drug refractory, symptomatic atrial fibrillation (AF). The number of AF ablation procedures has doubled in the past 4 years; in 2008, an estimated 80,000 AF ablation procedures were performed in the United States alone. Despite the increasing number of patients undergoing catheter ablation of AF, fundamental questions remain regarding procedural efficacy and safety.Atrioesophageal (AE) fistula is a rare but dreaded and devastating complication of catheter ablation for AF. Although the reported incidence is only about 0.03-0.2%, the resultant mortality is in excess of 75%. 1-3 Since the initial reports of this complication, an intense effort has been undertaken to understand the pathophysiology underlying this condition and to develop means to prevent this complication. What is now apparent is that the A-E fistula is just the "tip of the iceberg." 4 Milder forms of esophageal injury that range from esophageal erythema to intramural hemorrhage to frank esophageal ulcers can occur in a significant number of patients undergoing catheter ablation of AF. 5-8 With the addition of sophisticated imaging technologies such as radial endosonography, endoscopy can demonstrate morphological changes in the periesophageal connective tissue and the posterior wall of the left atrium (LA), even in the absence of gross changes in the esophageal mucosa. 4 Importantly, animal models suggest that these esophageal lesions are a form of thermal injury in that there is a linear relationship between the measured esophageal temperature and the frequency with which esophageal (and periesophageal) injury occurs as well as the size of individual lesions. 9,10 Over the past several years, investigators have reported on the merits of various intraprocedural interventions aimed at reducing the likelihood of inadvertent esophageal injury and thus an A-E fistula. These include some basic measures like reduction of energy when targeting the posterior LA wall or avoidance of lesions in this region and also techniques for real-time intraprocedural visualization of the esophagus, 11,12 monitoring of ablation lesions using intracardiac echocar-

Feasibility and clinical efficacy of left atrial ablation for the treatment of atrial tachyarrhythmias in patients with left atrial appendage closure devices

“…(-) We hypothesize that radiofrequency induced electrical current to the metal of the device might cause endothelial tissue damage and subsequent device related thrombus formation, similar to what has been described for LET probe. 13,14 RF delivery in close proximity to LAA-closure devices could result in erroneous impedance measurements and therefore automatic generator shut-off. While this has been previously reported in a ACP TM LAA-closure device 6 , no impedance interference occurred in our cohort, particularly in the patient who developed device thrombus.…”

The Last Shot for “One Shot” Pulmonary Vein Isolation with Radiofrequency Energy?

“…Thermal injury to the esophageal vasculature, which progresses to an ischemic lesion, is considered the precursor to an AEF. Thus, monitoring of the luminal esophageal temperature during ablation has become a widely accepted method to monitor for potential esophageal thermal injury . In this study, at least one instance of an esophageal temperature increase to >40.5 °C necessitating premature termination of ablation delivery was observed in 22 (51%) patients.…”

Steerable esophageal thermometer for atrial fibrillation ablation in a patient with esophageal achalasia: a case report

“…To avoid this kind of pitfall, we delivered the radiofrequency energy by placing the esophageal thermometer just on an opposite site of the ablation site with a temperature setting of less than 40°C. The relationship between an increase in the esophageal temperature and esophageal injury has to an extent already been established . Although the mechanisms of a paradoxical increase in esophageal injury with esophageal thermometer remain unclear, this methodology may also have helped provide a high safety level in this case.…”