AB-452654-3 AVOIDING THERMAL INJURY OF THE ESOPHAGUS BY USING LUMINAL ESOPHAGEAL TEMPERATURE MONITORING DURING HIGH-POWER, SHORT-DURATION RADIOFREQUENCY ABLATION: RESULTS OF A “ZERO TOLERANCE” PROTOCOL

Abstract

The prevention of esophageal thermal injury (ETI) during atrial fibrillation (AF) ablation is still a challenge and the optimal luminal esophageal temperature (LET) strategy remains to be proved. Recent studies showed a lower incidence (3.5- 6%) of endoscopic ETI during high-power, short-duration (HPSD) AF ablation in which radiofrequency (RF) delivery was tolerated at LET cutoff point of 39-41°C. We investigated whether the LET monitoring with “zero tolerance” towards any rise of temperature is a safe and effective strategy in terms of endoscopic ETI and acute pulmonary vein isolation (PVI) in HPSD ablation. Observational study of consecutive patients with symptomatic AF undergoing HPSD RF ablation. The previously estimated sample size was 87, considering an estimated prevalence of 6%, margin of error of 5%, and 95% of significance level. HPSD RF ablation was defined as maximum temperature at 43°C, power delivery at 50 or 40 W for 5 and 10 seconds, respectively (the lowest power was at the left atrium posterior wall [LAPW]), 20 ml/min., and contact force of 5-30 grams. The applications were monitored by the impedance curve and real-time LET using a 9F insulated single thermocouple temperature probe. The “zero-tolerance” protocol was defined as stopping the point-by-point RF delivery at any LET rise in the LAPW in which the tip of the temperature probe was always positioned, via fluoroscopy vision, at the closest ablation site. The RF application was resumed only after the LET fell back to the baseline. All patients were scheduled to undergo esophageal endoscopy 1-3 days after procedure. We included 87 consecutive patients (59±13 years, 62 [71%] males) with paroxysmal (58[66.6%] and persistence AF (29[33.3%]). PVI was achieved in all patients with 16±7 min. of fluoroscopy time and 168±38 min. of procedure time. The LET rose in 86 (98.8%) patients, with a mean peak temperature of 37.3±1.2°C. There were no major complications. All patients underwent esophageal endoscopy and no ETI was found. They were discharged on the day after the procedure and no complications, including esophagus perforation or atrio-esophageal fistula, were clinically detected in at least 3 months of follow-up. The LET monitoring with “zero tolerance” towards any rise of temperature in HPSD RF ablation of AF prevented the occurrence of endoscopic esophageal thermal lesion without compromising the acute PVI.