Esophageal Temperature Monitoring Research Articles

One-year freedom from arrhythmia following radiofrequency ablation using proactive oesophageal cooling

Abstract Background Proactive esophageal cooling is increasingly being utilized, and is now FDA cleared, to reduce the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation of atrial fibrillation (AF). One-year follow-up from the largest randomized controlled study, the IMPACT trial, showed a trend towards improvement in long-term efficacy versus luminal esophageal temperature (LET) monitoring. With larger data sets now available for analysis, we sought to determine 1-year freedom from atrial arrhythmia associated with the use of proactive esophageal cooling. Methods Data from 2 trials comparing freedom from atrial arrhythmia after RF ablation using proactive esophageal cooling to LET monitoring were combined. Data were analyzed using a stratified Cox proportional hazards model to compare arrhythmia recurrence rates, with R statistical analysis software. Results Data from 631 patients across two studies comparing arrhythmia outcomes for proactive oesophageal cooling versus LET monitoring were analysed. Mean patient age was 66.4±9.8 years, and 37.4% were female. Arrhythmias were 56.3% paroxysmal AF and 43.7% persistent or long-standing persistent AF. Freedom from atrial arrhythmia at one year was 77.2% for patients receiving proactive oesophageal cooling and 64.4% for patients receiving LET monitoring (Figure 1), with a hazard ratio for cooling of 0.65 (95% CI 0.43 to 0.99, P = 0.044). Conclusions Proactive oesophageal cooling was associated with significantly greater freedom from atrial arrhythmia at one year when compared to LET monitoring during RF ablation.

Acute and one-year procedural effects with proactive esophageal cooling during radiofrequency ablation with proactive esophageal cooling - comparison of paroxysmal and persistent atrial fibrillation

Abstract Background/Introduction Proactive esophageal cooling is FDA cleared to reduce the likelihood of ablation-related esophageal injury from radiofrequency (RF) cardiac ablation, and is becoming more prevalent as an alternative to luminal esophageal temperature (LET) monitoring. Data also suggest shorter procedure times and improved freedom from arrhythmia with esophageal cooling due to the lower continuity index achieved with esophageal cooling. Purpose To determine acute and long-term procedural outcomes of PVI for paroxysmal and persistent atrial fibrillation (AF) using active esophageal cooling. Methods Procedure times and one-year follow-up rhythm status of all patients treated with PVI for paroxysmal and persistent AF by a single operator were reviewed. Patients were treated over the time span February 2020 through July 2022. Procedure times and freedom from atrial arrhythmia were then compared between paroxysmal and persistent AF. Results A total of 317 patients with paroxysmal or persistent atrial fibrillation were treated over the course of the study timeframe. Of these patients, 167 (52.7%) had paroxysmal atrial fibrillation, and 150 had persistent AF. Mean age was 70.6±11.0 years (paroxysmal AF: 68.2±10.4 years and 43% female, persistent AF: 73.4±11.0 years and 37% female), with 40% female overall. Mean procedure time was 68.8±28.1 minutes (61.4 minutes for paroxysmal, 77.3 minutes for persistent). Most patients (224, or 71%) received no fluoroscopy, while the remainder received 1.28±4.0 minutes of fluoroscopy use. The KM estimate for freedom from atrial arrhythmia at one-year for paroxysmal patients was 81.4±3.9%. For persistent patients, the KM estimate for freedom from atrial arrhythmia at one-year was 70.4±4.4% (Figure 1). Conclusions Proactive esophageal cooling is associated with a high rate of long-term freedom from arrhythmia for both paroxysmal and persistent AF patients, as well as short procedure times, and the ability to achieve low or zero fluoroscopy use.Figure 1

Gastric hypomotility after adjunctive pulmonary vein and posterior wall isolation using cryoballoon in patients with atrial fibrillation: case control study

Abstract Background Pulmonary vein isolation (PVI) and concomitant electrical isolation of left atrial (LA) posterior wall (posterior wall box isolation [POBI]) using cryoballoon have mentioned as alternative ablation method for atrial fibrillation (AF). Gastric hypomotility (GH) is a possible complication of cryoballoon ablation (CBA); however, it remains unclear which factors are associated with GH during PVI plus POBI using cryoballoon. Objective We sought to investigate the clinical characteristics and intra-procedural parameters in AF patients with GH after PVI plus POBI using cryoballoon. Methods Forty-seven patients who underwent first-time CBA procedure for drug-refractory AF were enrolled. After the completion of ipsilateral superior and inferior PVI, cryoballoon was subsequently used to perform POBI; ablating in a segmental fashion for both superior and inferior portions of LA posterior wall. Intra-procedural luminal esophageal temperature (LET) monitoring, and postprocedural esophagogastroscopy within 72 hours were performed in all patients. In addition, intra-procedural parameters of CBA were comparatively evaluated between the patients with or without GH. Results Of overall enrolled patients (69.6 ± 9.6 years, 62% paroxysmal AF, CHA2DS2-VASc score 3.2 ± 1.7), GH were observed in 4 (8.6%) patients. Clinical characteristics were similar between the patients with and without GH, while the diameter of left inferior pulmonary vein ostium was significantly smaller in patients with GH compared with those without (15.0 ± 1.5mm vs. 18.8 ± 0.5mm; p=0.018). With regard to the intra-procedural parameters, minimum balloon temperatures at 30 seconds after CBA initiation during inferior portions of LA posterior wall, and minimum LET during POBI were significantly lower in patients with GH compared with those without (-43.3 ± 4.9°C vs. -37.2 ± 5.0°C; p=0.024, and 15.8 ± 1.0°C vs. 23.0 ± 6.0°C; p=0.022, respectively). The optimal cut-off values for prediction were -45°C (sensitivity 75%; specificity 92.5%), and 16.8°C (sensitivity 100%; specificity 85.4%), respectively. Conclusion Specific anatomical information and intra-procedural parameters aid identifying high-risk populations of GH after PVI plus POBI using cryoballoon.

Clinical utility of oesophageal temperature monitoring in AF ablation: An updated meta-analysis and review of literature

BackgroundAtrial fibrillation (AF) ablation can lead to oesophageal thermal injuries (ETI). These are thought to be the precursor of the much rarer but frequently fatal atrio-oesophageal fistulas. Many centers performing AF ablation routinely use oesophageal temperature monitoring (ETM). This meta-analysis aims to determine the utility of ETM in preventing ETI in the context of radiofrequency catheter ablation of AF. MethodsA systematic search of PubMed, Embase databases and Cochrane registry was performed comparing ETI between ETM and non-ETM strategies in AF ablation. Data on endoscopically determined ETI, AF recurrence, procedure time and ablation time were extracted. Statistical analyses including subgroup and covariate analyses were performed using random effect model in R platform. ResultsETI were similar in both ETM (n = 864) and non- ETM groups (n = 639) (RR 1.04, 95 % CI 0.34–3.23) across 12 studies. AF recurrence was statistically similar in both groups (IRR 0.92, 95 % CI 0.73–1.17) but showed a lower trend in non-ETM group. Ablation time was numerically lower in the ETM group and procedure time was numerically higher trend in the ETM group; but they were not statistically significant. Covariate analysis found that posterior wall ablation power setting, additional linear ablation, BMI, use of GA or prophylactic PPI after ablation had no significant correlation in the incidence of ETI. ConclusionETM was not associated with a reduced incidence of ETI during AF ablation. Evidence supporting the routine use of ETM to reduce the risk of ETI or atrio-oesophageal fistulas is lacking.

Determination of Continuity Index Values in Atrial Fibrillation Ablation with Proactive Esophageal Cooling.

Radiofrequency (RF) ablation to perform pulmonary vein isolation (PVI) for the treatment of atrial fibrillation involves some risk to collateral structures, including the esophagus. Proactive esophageal cooling using a dedicated device has been granted marketing authorization by the Food and Drug Administration (FDA) to reduce the risk of ablation-related esophageal injury due to RF cardiac ablation procedures, and more recent data also suggest that esophageal cooling may contribute to improved long-term efficacy of treatment. A mechanistic underpinning explaining these findings exists through the quantification of lesion placement contiguity defined as the Continuity Index (CI). Kautzner et al. quantified the CI by the order of lesion placement, such that whenever a lesion is placed non-adjacent to the prior lesion, the CI is incremented by the number of segments the catheter tip has moved over. To facilitate real-time calculation of the CI and encourage further adoption of this instrument, we propose a modification in which the placement of non-adjacent lesions increments the CI by only one unit, avoiding the need to count potentially nebulous markers of atrial segmentation. The objective of this protocol is to describe the methods of calculating the CI both prospectively during real-time PVI cases and retrospectively using recorded case data. A comparison of the results obtained between cases that utilized proactive esophageal cooling and cases that used luminal esophageal temperature (LET) monitoring is then provided.

Association between proactive esophageal cooling and increased lab throughput.

Proactive esophageal cooling has been FDA cleared to reduce the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation procedures. Data suggest that procedure times for RF pulmonary vein isolation (PVI) also decrease when proactive esophageal cooling is employed instead of luminal esophageal temperature (LET) monitoring. Reduced procedure times may allow increased electrophysiology (EP) lab throughput. We aimed to quantify the change in EP lab throughput of PVI cases after the introduction of proactive esophageal cooling. EP lab throughput data were obtained from threeEPgroups. We then compared EP lab throughput over equal time frames at each site before (pre-adoption) and after (post-adoption) the adoption of proactive esophageal cooling. Over the time frame of the study, a total of 2498 PVIs were performed over a combined 74 months, with cooling adopted in September 2021, November 2021, and March 2022 at each respective site. In the pre-adoption time frame, 1026 PVIs were performed using a combination of LET monitoring with the addition of esophageal deviation when deemed necessary by the operator. In the post-adoption time frame, 1472 PVIs were performed using exclusively proactive esophageal cooling, representing a mean 43% increase in throughput (p < .0001), despite the loss of two operators during the post-adoption time frame. Adoption of proactive esophageal cooling during PVI ablation procedures is associated with a significant increase in EP lab throughput, even after a reduction in total number of operating physicians in the post-adoption group.

Prevention of esophageal lesions during atrial fibrillation catheter ablation using esophageal temperature monitoring: A systematic review and meta-analysis.

The use of esophageal temperature monitoring (ETM) for the prevention of esophageal injury during atrial fibrillation (AF) ablation is often advocated. However, evidence supporting its use is scarce and controversial. We therefore aimed to review the evidence assessing the efficacy of ETM for the prevention of esophageal injury. We performed a meta-analysis and systematic review of the available literature from inception to December 31, 2022. All studies comparing the use of ETM, versus no ETM, during radiofrequency (RF) AF ablation and which reported the incidence of endoscopically detected esophageal lesions (EDELs) were included. Eleven studies with a total of 1112 patients undergoing RF AF ablation were identified. Of those patients, 627 were assigned to ETM (56%). The overall incidence of EDELs was 9.8%. The use of ETM during AF ablation was associated with a non significant increase in the incidence of EDELs (12.3% with ETM, vs. 6.6 % without ETM, odds ratio, 1.44, 95%CI, 0.49, 4.22, p=.51, I2=72%). The use of ETM was associated with a significant increase in the energy delivered specifically on the posterior wall compared to patients without ETM (mean power difference: 5.13 Watts, 95% CI, 1.52, 8.74, p=.005). The use of ETM does not reduce the incidence of EDELs during RF AF ablation. The higher energy delivered on the posterior wall is likely attributable to a false sense of safety that may explain the lack of benefit of ETM. Further randomized controlled trials are needed to provide conclusive results.

Machine learning identifies esophageal luminal temperature patterns associated with thermal injury in catheter ablation for atrial fibrillation.

Luminal esophageal temperature (LET) monitoring during atrial fibrillation (AF) ablation is widely used to reduce the incidence of endoscopically detected esophageal lesion (EDEL). We sought to assess whether specific patterns of LET variation are associated with EDEL. A high-fidelity multisensor probe was used to record LET in AF patients undergoing radiofrequency ablation (RFA) or cryoballoon ablation (CBA). Explainable machine learning and SHapley Additive exPlanations (SHAP) analysis were used to predict EDEL and assess feature importance. A total of 94 patients (38.3% persistent AF, 71.3% male, 72 RFA, and 22 CBA) were included. EDEL was detected in 11 patients (10 RFA and one CBA). In the RFA group, the highest LET recorded was similar between patients with and without EDEL (40.6 [40.1-41]°C vs. 40.2 [39.1-40.9]°C; p = .313), however, the rate of LET rise for the highest recorded peak was higher (0.08 [0.03-0.12]°C/s vs. 0.02 [0.01-0.05]°C/s; p = .033), and the area under the curve (AUC) for the highest peak was smaller (412.5 [206.8-634.1] vs. 588.6 [380.4-861.1]; p = .047) in patients who had EDEL. In case of CBA, the patient with EDEL had a faster LET decline (0.12 vs. 0.07 [0.02-0.14]°C/s), and a smaller AUC for the lowest trough (2491.3 vs. 2629.3 [1712.6-5283.2]). SHAP analysis revealed that a rate of LET change higher than 0.05°C/s and an AUC less than 600 were more predictive of EDEL in RFA. The rate of LET change and AUC for the recorded temperature predicted EDEL, whereas absolute peak temperatures did not.

Esophageal Versus Rectal Temperature Monitoring During Whole-Body Therapeutic Hypothermia for Hypoxic–Ischemic Encephalopathy: Association with Short- and Long-Term Outcomes

To compare the short- and long-term outcomes of infants with hypoxic-ischemic encephalopathy (HIE) treated with whole-body therapeutic hypothermia (TH), monitored by esophageal vs rectal temperature. We conducted a secondary analysis of the multicenter High-Dose Erythropoietin for Asphyxia and Encephalopathy (HEAL) trial. All infants had moderate or severe HIE and were treated with whole-body TH. The primary outcome was death or neurodevelopmental impairment (NDI) at 22-36months of age. Secondary outcomes included seizures, evidence of brain injury on magnetic resonance imaging, and complications of hypothermia. Logistic regression was used with adjustment for disease severity and site as clustering variable because cooling modality differed by site. Of the 500 infants who underwent TH, 294 (59%) and 206 (41%) had esophageal and rectal temperature monitoring, respectively. There were no differences in death or NDI, seizures, or evidence of injury on magnetic resonance imaging between the 2 groups. Infants treated with TH and rectal temperature monitoring had lower odds of overcooling (OR 0.52, 95% CI 0.34-0.80) and lower odds of hypotension (OR 0.57, 95% CI 0.39-0.84) compared with those with esophageal temperature monitoring. Although infants undergoing TH with esophageal monitoring were more likely to experience overcooling and hypotension, the rate of death or NDI was similar whether esophageal monitoring or rectal temperature monitoring was used. Further studies are needed to investigate whether esophageal temperature monitoring during TH is associated with an increased risk of overcooling and hypotension.

Esophageal injury, perforation, and fistula formation following atrial fibrillation ablation.

Esophageal perforation and fistula formation are rare but serious complications following atrial fibrillation ablation. In this review article, we outline the incidence, pathophysiology, predictors, and preventative strategies of this dreaded complication. We conducted an electronic search in 10 databases/electronic search engines to access relevant publications. All articles reporting complications following atrial fibrillation ablation, including esophageal injury and fistula formation, were included for systematic review. A total of 130 manuscripts were identified for the final review process. The overall incidence of esophageal injury following atrial fibrillation ablation was significantly higher with thermal ablation modalities (radiofrequency 5-40%, cryoballoon 3-25%, high-intensity focused ultrasound < 10%) as opposed to non-thermal ablation modalities (no cases reported to date). The incidence of esophageal perforation and fistula formation with the use of thermal ablation modalities is estimated to occur in less than 0.25% of all atrial fibrillation ablation procedures. The use of luminal esophageal temperature monitoring probe and mechanical esophageal deviation showed protective effect toward reducing the incidence of this complication. The prognosis is very poor for patients who develop atrioesophageal fistula, and the condition is rapidly fatal without surgical intervention. Esophageal perforation and fistula formation following atrial fibrillation ablation are rare complications with poor prognosis. Various strategies have been proposed to protect the esophagus and reduce the incidence of this fearful complication. Pulsed field ablation is a promising new ablation technology that may be the future answer toward reducing the incidence of esophageal complications.

Improvement in post-ablation chest pain and same-day discharge with the use of active esophageal cooling

Abstract Background Active esophageal cooling is a common method of esophageal protection during radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF). Compared to the main alternative, luminal esophageal temperature (LET) monitoring, active esophageal cooling reduces esophageal injury. Recent findings in the community hospital setting indicate that procedure time and post-ablation chest pain may also be reduced, leading to greater same-day patient discharge. Objective We aimed to compare the differences in same-day discharge rates and patient-reported post-ablation chest pain between patients treated with either LET monitoring or active esophageal cooling while undergoing RF ablation in a large academic medical center. Methods We reviewed data from RF ablations performed between January 2020 and October 2022 by five attending electrophysiologists and four electrophysiology fellows. These data were extracted from Epic’s Clarity database by two clinical informaticists. Extracted data points were paired with a manual chart review of inbound phone calls, electronic messages, follow-up visits, and readmissions within 30 days of the procedure. Results A total of 175 patients underwent RF ablation between January 2020 and October 2022, with 63 (36%) patients treated with LET monitoring and 112 (64%) treated with active esophageal cooling. Chest pain was reported by 11 patients (18%) in the LET monitored group and 7 patients (6%) in the actively cooled group (P=&amp;lt;0.001). Of the patients treated with LET monitoring, 13 (20.6%) were discharged within 12 hours of admission compared to 44 (39.3%) of the patients treated with active esophageal cooling (P=0.016). Conclusions The adoption of active esophageal cooling during RF ablation was associated with less postoperative chest pain and increased same-day discharge rates.

Impact of active esophageal cooling on catheter ablation procedure times across five healthcare systems

Abstract Background Increased efficiency in procedure times may improve electrophysiology lab throughput and enhance patient care. The choice of esophageal protection method during pulmonary vein isolation (PVI) can affect procedural efficiency, with recent data suggesting that active esophageal cooling is associated with shorter procedure times when compared with luminal esophageal temperature (LET) monitoring. Objective To compare PVI procedure times before and after the adoption of active esophageal cooling in a large multicenter analysis. Methods Procedural data were obtained from 5 hospital systems before and after they adopted active esophageal cooling. Patient age, gender, and total procedure time were recorded and compared between groups before and after adoption of esophageal cooling. Results A total of 2,280 patient procedures completed by 16 different physiologists were reviewed from a total of 6 hospitals. The hospitals included academic medical centers, community hospitals, and integrated healthcare delivery systems. Prior to adopting active esophageal cooling, patients were treated with LET monitoring using either single or multi-sensor temperature probes. For the actively cooled patients the mean age was 66.7 ± 10.9 years and 33.5% were female. For the LET monitored patients the mean age was 64.2 ± 10.7 years and 34.5% were female. A total of 928 patients were treated with LET monitoring, with a mean procedure time of 173 ± 73 minutes. A total of 1352 patients were treated with active esophageal cooling, with a mean procedure time of 113 ± 51 minutes, representing a decrease of 60 minutes, or 34.7% of procedure time, compared with active esophageal cooling (P&amp;lt;.001). Conclusions Active esophageal cooling during PVI was associated with up to a 34.7% reduction in procedure duration when compared to LET monitoring in this large multicenter analysis.

Atrioesophageal Fistula Rates Before and After Adoption of Active Esophageal Cooling During Atrial Fibrillation Ablation

BackgroundActive esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. A formal analysis of the atrioesophageal fistula (AEF) rate with active esophageal cooling has not previously been performed. ObjectivesThe authors aimed to compare AEF rates before and after the adoption of active esophageal cooling. MethodsThis institutional review board (IRB)-approved study was a prospective analysis of retrospective data, designed before collecting and analyzing the real-world data. The number of AEFs occurring in equivalent time frames before and after adoption of cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were quantified across 25 prespecified hospital systems. AEF rates were then compared using generalized estimating equations robust to cluster correlation. ResultsA total of 14,224 patients received active esophageal cooling during RF ablation across the 25 hospital systems, which included a total of 30 separate hospitals. In the time frames before adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In the preadoption cohort, a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates for procedures using LET monitoring. In the postadoption cohort, no AEFs were found in the prespecified sites, yielding an AEF rate of 0% (P < 0.0001). ConclusionsAdoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

Implementation of CLOSE protocol for pulmonary vein isolation in paroxysmal atrial fibrillation by young electrophysiologists in real world clinical practice

Abstract Funding Acknowledgements Type of funding sources: None. Background Paroxysmal atrial fibrillation (AF) is widely treated by radiofrequency (RF) catheter ablation. The CLOSE protocol has been proposed and accepted to guide a successful, safe and durable pulmonary vein isolation in patients with paroxysmal AF. However, the reproducibility of the protocol in real clinical practice and on less experienced hands is less established. Objective To assess the acute effectiveness, safety and reproducibility of RF catheter ablation based on the CLOSE protocol for pulmonary vein isolation in paroxysmal AF patients, performed by young electrophysiologists with less than 5 years of experience. Methods Fifty consecutive patients (25 men, aged 61±11 years) with symptomatic paroxysmal AF were enrolled during the period 2020- 2021. RF catheter ablation based on the CLOSE protocol, using a conventional contact force sensing catheter (Thermocool SmartTouch ST D/F) and a circumferential multipolar catheter (Lasso) after double transseptal puncture (2 SL0 long sheaths), under general anesthesia and oesophageal temperature monitoring was performed in all patients. Results Pulmonary vein isolation demonstrated by entrance and exit block was achieved in all patients. Total procedure time was 147 ± 29 minutes, exposure X-ray time was 5.36 ± 4.46 minutes and exposure dose was 922 ± 1616 cGy*cm2. Left pulmonary veins (LPVs) first pass isolation (94%) was numerically higher than the right pulmonary veins (RPVs) first pass isolation (82%). There were not safety issues. In comparison with the results reported by the authors of the CLOSE protocol, the procedure time was similar (p= 0.84), however, the exposure X-ray time and the exposure dose were significantly lower in our study (p&amp;lt;0.0001 and p=0.01, respectively). The rates of first pass isolation of left and right pulmonary veins did not differ when compared to the respective rates reported by the CLOSE protocol authors (82% vs CLOSE 100% for RPVs and 94% vs CLOSE 97% for LPVs, p&amp;gt; 0.05 for both). Conclusions RF catheter ablation in paroxysmal AF patients using the CLOSE protocol is highly effective, safe and reproducible not only by experienced but also by young electrophysiologists. Adaptation of an ablation strategy for pulmonary vein isolation based on the CLOSE protocol may improve the workflow of the procedure and the training curve of young electrophysiologists without compromising the efficacy and safety.

Reduction in procedure duration when utilizing active esophageal cooling in patients with persistent atrial fibrillation - update from a large hospital registry

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart, Lung, And Blood Institute of the National Institutes of Health. Background During left atrial ablation, lesions may be placed on the posterior wall of the left atrium. Due to the anatomical proximity of the left atrium to the esophagus, there is significant risk for thermal esophageal injury and potentially atrio-esophageal fistula. Ablation of persistent atrial fibrillation (AF) may involve even more lesion placement, and increased risk and procedure time as a result. In order to protect the esophagus, there are two main methods of esophageal protection, luminal esophageal temperature (LET) monitoring and active esophageal cooling. Recent studies have compared LET monitoring to active cooling and found a reduction in overall esophageal injury when utilizing active cooling, in addition to a reduction in procedure time. However, these studies generally included all patients with AF regardless of which type. Purpose We aimed to investigate the association between procedure duration and esophageal protection method among persistent AF patients. Methods In this study, we obtained data from an existing clinician-maintained hospital registry. We collected procedure durations from patients with persistent AF undergoing left atrial ablation from January 2018 to May 2022. All patients that met these criteria were included. Results Data were analyzed from 161 patients. Active esophageal cooling was utilized in 90 procedures, while LET monitoring was utilized in 71 procedures. The median procedure duration in the actively cooled group was 146 minutes with an interquartile range (IQR) of 58. The median procedure duration in the LET monitored group was 173 minutes with an IQR of 60. This represents a median difference of 27 minutes or 16% of the total procedure duration (p&amp;lt;.001) Conclusions The use of active esophageal cooling is associated with a significant reduction in overall procedure time among patients with persistent atrial fibrillation.

Meta-analysis on clinical utility of oesophageal temperature monitoring in AF ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) ablation can lead to oesophageal thermal injury (ETI) and atrio-oesophageal fistulas can be fatal. Although temperature probes are widely utilized in AF ablations worldwide, in the United Kingdom, AF ablation procedures are performed under local anaesthesia and sedation and not all centres have adopted routine use of temperature probes. This may be due to comparative studies to detect the role of oesophageal temperature monitoring (ETM) in AF ablation showing mixed results. Clinical utility of ETM-guided AF ablation remains debatable, and studies have reported pulmonary vein recurrences in the areas of limited radiofrequency application due to cautious ETM-guided ablation. Purpose This meta-analysis aims to determine the utility of ETM in preventing ETI in the context of radiofrequency catheter ablation of AF. Methods A systematic search of PubMed, Embase databases and Cochrane registry was performed comparing ETI between ETM and non-ETM-guided strategies in AF ablation. Primary outcome was endoscopically detected ETI. Secondary outcomes were AF recurrence, procedure time and ablation time. Statistical analyses including subgroup and covariate analyses were performed using random effect model. Results Baseline: 12 studies (one randomized study, 7 from Germany) satisfied the inclusion criteria; only two studies had patients undergoing AF ablation under GA; 9 studies utilized multi-sensor temperature probes; temperature cut-off ranged from 38.5 ℃ to 42 ℃; posterior wall power setting ranged from 15W to 35W (Figure 1). Primary outcome: ETI were similar in both ETM (n=864) and non- ETM groups (n=639) (RR 1.04, 95% CI 0.34-3.23, I2 =72%) (Figure 2A). Temperature cut-offs, posterior wall power setting, additional linear ablations or body mass index (BMI) had no significant effect on ETI in bivariate or multivariate analysis. Secondary outcome: AF recurrence was statistically similar in both groups (IRR 0.92, 95% CI 0.73-1.17, I2 =0%) but showed a lower trend in non-ETM group (Figure 2B). Ablation time (SMD -0.08, 95% CI -0.37- 0.21, I2 =65%) was numerically lower in the ETM group but was not statistically significant (Figure 2C). Procedure time (SMD 0.96, 95% CI 0.69- 2.61, I2 =97%) was statistically similar across both groups but showed a higher trend in the ETM group (Figure 2D). Major complications of both ETM and non-ETM groups, including atrio-oesophageal fistula, were extremely rare. Conclusion ETM did not make statistically significant difference in the resultant ETI during AF ablation. There was a trend towards longer procedures with marginally lower RF application time. While use of temperature probes continues to be limited in the UK centres, the clinical utility of oesophageal temperature remains questionable and need to be addressed in randomized studies. However our analyses cannot be generalized to high power ablation settings (e.g. 50W or 90W) or RF balloons.

PO-01-104 3D MODELING OF PRE-PROCEDURE CT SCAN TO PREDICT SEVERE ESOPHAGEAL HEATING DURING HIGH POWER SHORT DURATION ATRIAL FIBRILLATION ABLATION

The degree of esophageal heating during left atrial posterior wall (LAPW) ablation is a powerful predictor of esophageal injury. Esophageal temperature monitoring has not been shown, however, to reduce esophageal injury risk related to atrial fibrillation (AF) ablation. Esophageal proximity modeling based on pre-procedure CT scan using ADAS 3D software (ADAS3D Medical, Barcelona, Spain) is a novel method of identifying left atrial locations at high risk for severe esophageal heating. Given the mobile nature of the esophagus relative to the LAPW, the predictive value of esophageal proximity mapping is unclear. To determine the predictive value of esophageal proximity mapping to identify LAPW ablation sites at risk for severe esophageal heating. Pre-procedure CT scans were analyzed using ADAS 3D software in 10 patients undergoing AF ablation to create a 3D esophageal proximity model and left atrial tissue thickness map that were merged with a catheter based left atrial electroanatomic map (Ensite X, Abbott, Inc.). Esophageal proximity was defined as: Zone 1 – overlying esophagus, Zone 2 – within 5 mm of esophagus, or Zone 3 – > 5 mm from esophagus. LAPW ablation lesions were created with a contact-force sensing radiofrequency ablation catheter (Tacticath, Abbott, Inc.) at 45W, 10-20g of force, and 6 seconds duration. A 12 sensor esophageal temperature probe (Circa, Circa Scientific, Inc.) recorded the temperature increase related to each LAPW lesion. Ablation lesions in Zone 3 resulted in significantly lower esophageal temperature rise (degrees Celsius) as compared to either Zone 1 (mean 0.11 ± 0.27 vs 1.61 ± 1.39, p value <0.0001) or Zone 2 (mean 0.11 ± 0.27 vs 0.84 ± 1.1, p value <0.0001) (Fig A). Lesions in Zone 2 resulted in lower temperature rise as compared to Zone 1 (mean 0.84 ±1.1 vs. 1.61 ± 1.39, p value <0.0001) (Fig A). Within Zones 1 and 2, lesions with LAPW thickness > 2 mm resulted in significantly less esophageal temperature rise as compared to those on tissue with thickness of ≤ 2 mm (Fig B). Ablation lesions delivered >5mm from esophageal location at time of pre-procedure CT scan are very unlikely to result in significant esophageal heating. Ablation sites overlying esophagus with LAPW thickness ≤ 2mm were at greatest risk of significant esophageal heating. Analysis of pre-procedure CT scans to determine esophageal proximity and LAPW thickness may be useful in developing strategies to avoid esophageal injury during LAPW RF ablation.

AB-452654-1 ESOPHAGEAL PROTECTION STRATEGIES FOR ABLATION OF ATRIAL FIBRILLATION: COMPARATIVE RESULTS BASED ON CONSECUTIVE ENDOSCOPIC EVALUATION

Catheter ablation is an effective treatment for restoring sinus rhythm in AF and has become a worldwide procedure. Although rare, atrioesophageal fistula (AEF) is among the most common lethal complications of this procedure. Several strategies have been employed to prevent esophageal lesions, including single and multi-sensor esophageal probes, different energy strategies, esophageal displacement and regular esophageal monitoring using esophagogastroduodenoscopy (EGD) to identify asymptomatic esophageal lesions that could evolve to AEF. As the occurrence of AEF is rare, one of the approaches to evaluate which strategy is more effective in preventing esophageal lesions is studying the incidence of asymptomatic on routine endoscopy. The objective of this study is to present the five-year experience of a systematic endoscopic surveillance of esophageal injury after AF catheter ablation and analyse if there is an appropriate strategy related to a lower incidence of lesions. This is a retrospective single center registry of all AF ablation procedures performed from 2016 to 2021, in which an endoscopy was performed after ablation in all cases. A total of 660 AF ablation procedures in 626 different patients were performed in that period. A control EGD data could be recorded in 609 ablation procedures (92,3%). Most of the patients were male with paroxysmal AF. Esophageal temperature monitoring with single Sensor Probe was performed in 48.4% and with multi–sensor probe in 24.4% of the cases. Most of the patients presented no esophageal lesions (71.8%). Mild lesion was found on 90 patients (14.8%) and severe lesion was found on 56 (9.2%) of them. The use of multisensor esophageal probe (P<0.001), male gender (P=0.007) and the use of PVAC (P=0.018) were correlated with less frequent thermal lesions on multivariate analysis. Most of the lesions were healed on control endoscopy. The incidence of esophageal lesions on routine EGD after AF catheter ablation is high, but most of the cases the lesion is spontaneously healed. The use of multisensor probe, PVAC and male gender were correlated to fewer thermal lesions.

PO-01-092 FIRST RESULTS FROM PVI WITH A NOVEL RADIOFREQUENCY BALLOON-CATHETER FOR THE TREATMENT OF PAROXYSMAL AND PERSISTENT ATRIAL FIBRILLATION

For patients with symptomatic atrial fibrillation (AF) pulmonary vein isolation (PVI) has evolved to the standard of care. For minimization of pulmonary vein reconnection, for reduction of complications and for improvement of PVI efficiency, also in a timely manner, many catheter technologies have been developed already. A new ablation modality in that regard is the radiofrequency balloon-catheter (RF-BC). However the evidence concerning this new technology is sparse. Evaluation of the procedural data, the safety profile and the clinical outcome using the new RF-BC in PVI. Since September 2021 patients with first-time PVI using the RF-BC (HELIOSTAR™, Biosense Webster) have been included in our ongoing monocentric register study. Esophageal temperature (ET) and phrenic nerve (PN) monitoring is performed during energy delivery. In case of ET exceedence above 42 degree Celsius an esophagogastroscopy (EGD) is conducted. Follow-up is scheduled for 3, 6, 12 and 24 months post ablation and in case of symptomatic recurrence. Until now 130 individuals (age [y]: 69 ± 9.8, female: 37.7%, paroxysmal AF 64.6%, CHA2DS2-VASc 4 ± 3, preserved ejection fraction 56.2%, left atrial diameter [mm] 45 ± 8.3) have been included in our study. Mean procedural duration (skin-to-skin) was 88 (± 35) minutes. Single-shot-isolation was possible in 80,2% of the 516 treated PVs. On average five energy deliveries per patient had been applied. Fortunately no pericardial tamponade, no stroke and no fatalities occurred. Nevertheless PN palsy was detected in one patient. Luckily it resolved completely within 48h. Due to ET exceedence in 6 of 20 patients esophageal lesions have been detected during EGD. All 6 lesions resolved spontaneously. Recurrence-free-survival after 6 months was 73.0% in the Kaplan-Meier analysis if no blanking period is applied, and 94.0% with a 90-day blanking period. Thanks to pulmonary vein isolation with only one energy-delivery in most cases, the RF-BC seems to be a very efficient ablation tool. But more importantly is seems to be also a safe one.

PO-02-033 CALCULATED LUMINAL ESOPHAGEAL TEMPERATURE DATA PREDICT ESOPHAGEAL INJURY FOLLOWING RADIOFREQUENCY PULMONARY VEIN ISOLATION

Luminal esophageal temperature (LET) monitoring does not prevent esophageal injury following pulmonary vein isolation (PVI) but LET excess (i.e. > 41°C) is associated with increased risk for esophageal lesions and fistula. Detailed analysis of LET data may better predict the risk for any esophageal injury (mucosal lesions, periesophageal edema and food retention), and thus to streamline follow-up/therapy to prevent progression to fistula. LET data (S-Cath Circa, 12 thermocouples [Fig. 1A]) of consecutive patients with radiofrequency (RF) PVI (30 Watt at the left atrial posterior wall) were analyzed offline. Ablation was stopped when LET exceeded 41.0°C. LET-maxima, duration of LET rise [Fig. 1B], area under the maximum LET curve of any thermocouple (AUCmax [Fig. 1B]) and summed-up AUC of all individual LET-curves of the 12 thermocouples (3D-AUC [Fig. 1C]) were calculated and correlated with the results of endoscopy (EGD [mucosal lesions, food retention]) and endoscopic ultrasound (EUS [edema]). The calculated parameters were analyzed with regard to their ability to predict (sensitivity) or exclude (specificity) esophageal injury [Fig. 1D]. Following RF-PVI, 81 patients were studied by EGD+EUS (n=73) or EGD alone (n=8). Any esophageal injury was observed in 33/73 (mucosal lesions: 12/81, edema: 27/73, food retention: 13/81). Procedural data of PVI were not different between patients with/without esophageal injury. (1) LET > 41.8°C was associated with mucosal lesions but raw temperatures were not able to predict esophageal injury. (2) Duration of any LET-rise above baseline differed significantly with/without esophageal injury and performed even better for duration above 38.0°C (median time [interquartile range] exceeding 38.0°C 542 [298/668]s with vs. 289 [143/414]s without injury). (3) Summed-up area under the curve for LET exceeding 38.0°C (3D-AUC > 38.0°C) was the best predictive parameter and significantly increased in patients with esophageal injury (882 [448/1181]K.s with vs. 421 [170/691]K.s without injury [sensitivity 70%, specificity 83%, Youden-index 0.52, p<0.001]). AUC of the LET curves best predicted esophageal injury following RF-PVI with sensitivity and specificity ranging from 70-80% (Fig. 1D). Whether online-assessment of AUC is useful to guide PVI strategy and to prevent esophageal injury remains to be seen.