47 * Oesophageal temperature probe during atrial fibrillation radiofrequency catheter ablation: friend or foe?

Abstract

Introduction: Oesophageal temperature monitoring during atrial fibrillation (AF) ablation is one of the suggested strategies to prevent atrioesophageal fistula. It is not known whether temperature alerts that lead to early termination of RF and/or reduction in power prevent lesion durability and promote acute and chronic pulmonary vein (PV) reconnection. Methods: At our institution all AF ablations performed under general anaesthesia have oesophageal temperature monitoring using the 5-pole Sensitherm (St Jude Medical). The probe can be visualised on the 3D electroanatomic Velocity geometry. During the ablation procedure any sites that cause a temperature rise of >39oC and premature cessation of RF and/or reduction in power (20-25W) during wide area encirclement are labelled on the geometry in a different colour from standard, complete and uninterrupted RF lesions (30-40W, minimum 15-20 seconds in a stable position). The study population consisted of all patients (pts) returning for a 1st redo ablation from November 2012 to May 2014. The site(s) of PV reconnection as determined by multipolar catheter mapping and successful re-isolation RF lesions were labelled on the 3D geometry and compared with lesion markers from the initial procedure. For both the initial and redo procedure the temperature probe position relative to the PV veins and posterior wall was recorded as left, mid or right segment. Results: There were 54 pts undergoing 1st redo procedures: 36 males, mean age 68±9,22 (41%) paroxysmal and 32 (59%) persistent AF. At the time of the index procedure, the probe was left-sided in 22 pts (41%), right-sided in 20 pts (37%) and in the mid-wall segment in 12 pts (22%). An oesophageal shift (change in segment) was found in 10 pts at time of the follow up procedure. Thirty pts (56%) had at least one temperature alert during the index procedure, affecting 46 PVs (21% of a total of 216 PVs). The median length of lesions causing alerts was 21 (16-26) mm for LPVs and 18 (15-25) mm for RPVs. The distribution of temperature alerts at the initial procedure was LSPV 24%, LIPV 33%, RSPV 13%, RIPV 30%. In 12 patients there were 23 PVs that had acute reconnection requiring further ablation. There was no correlation between acute PV reconnection and temperature alerts (p=0.5). At the time of the redo procedure, 103 PVs were found to be reconnected in 44 patients. No correlation was found between the occurrence of temperature alerts at the initial procedure and chronic reconnection in the associated pulmonary vein (p=0.27). Conclusion: Just over half of patients undergoing PV isolation will have an oesophageal temperature alert. Reducing power and RF duration does not increase or decrease the incidence of subsequent PV reconnection. Temperature probe-guided ablation may therefore increase safety without compromising ablation efficacy.