Luminal Esophageal Temperature 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.

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.

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

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.

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 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.

EsophAguS Deviation During RadiofrequencY Ablation of Atrial Fibrillation: The EASY AF Trial

BackgroundInjury to the esophagus has been reported in a high percentage of patients undergoing ablation of atrial fibrillation (AF). ObjectivesThis study assessed the incidence of esophageal injury in patients undergoing ablation of AF with and without an esophageal deviating device. MethodsThis prospective, randomized, multicenter, double-blinded, controlled Food and Drug Administration investigational device exemption trial compared the incidence of ablation-related esophageal lesions, as assessed by endoscopy, in patients undergoing AF ablation assigned to a control group (luminal esophageal temperature [LET] monitoring alone) compared with patients randomized to a deviation group (esophagus deviation device + LET). This novel deviating device uses vacuum suction and mechanical deflection to deviate a segment of the esophagus, including the trailing edge. ResultsThe data safety and monitoring board recommended stopping the study early after randomizing 120 patients due to deviating device efficacy. The primary study endpoint, ablation injury to the esophageal mucosa, was significantly less in the deviation group (5.7%) in comparison to the control group (35.4%; P < 0.0001). Control patients had a significantly higher severity and greater number of ablation lesions per patient. There was no adverse event assigned to the device. By multivariable analysis, the only feature associated with reduced esophageal lesions was randomization to deviating device (OR: 0.13; 95% CI: 0.04-0.46; P = 0.001). Among control subjects, there was no difference in esophageal lesions with high power/short duration (31.8%) vs other radiofrequency techniques (37.2%; P = 0.79). ConclusionsThe use of an esophageal deviating device resulted in a significant reduction in ablation-related esophageal lesions without any adverse events.

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.

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.

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.

AB-453068-3 ESOPHAGEAL TEMPERATURE AND ESOPHAGEAL DAMAGE IN HIGH POWER SHORT DURATION ABLATION SETTINGS

Radiofrequency ablation (RFA) of atrial fibrillation (AF) using high-power short-duration (HPSD) ablation settings (50W, 10s or up to 90W, 4s) are increasingly common, seeking to maximize resistive rather than conductive heating to limit the risk of esophageal damage. The real-time luminal esophageal temperature (LET) response and the risk of esophageal damage of HPSD are not fully established. To investigate the LET and esophageal risk of HPSD RFA on the posterior LA wall. We ablated the deep inferior pulmonary vein (IPV) in close proximity to the esophagus in 14 pigs, using either Termocool SmartTouch Catheter (HPSD 50W/10s, n=7), or QDOT Catheter (HPSD 90W/4s, n=7). LET was monitored with a 12-sensor CIRCA probe. RFA was delivered in the IPV in apposition with the esophagus as verified on 3D maps. We collected LET, ablation parameters; endoscopy, macro- and microscopic examination of the esophagus. In 3 pigs in each group, survival was prolonged 1 month for chronic characterization of esophageal lesions. Total energy delivered (90W/4s vs. 50W/10s) was higher in QDOT group (60.8±18.8W vs. 48.9±0.1W, p<0.005), as was the peak temperature at ablation catheter tip (51.2±3.1°C vs. 25.3±2.8°C, p<0.005). Peak LET was lower in the 90W/4s group than in the 50W/10s group, (38.7±1.5°C vs. 40.5±3.1°C, p<0.005). Temperatures >40°C were reached in 14/90 90W/4s ablations vs 43/94 in 50W/10s ablations (p<0.001). Acute esophageal lesions were found in all pigs. In the 90W/4s group, acute lesions involved affecting outer muscularis layer in 4/4 and up to submucosa in 1/4. However, no chronic lesions were identified in 3/3. In the 50W/10s group: 4/4 acute lesions involved entire muscularis layer into the submucosa, and reaching the mucosa in 2. Chronic lesions were found in only 1 on pig in the 50W/10s group – complete muscularis layer replacement with scar (with submucosal inflammation). All lesions occurred after high LETs. (Figure) HPSD 50W/10s can create high LET and significant acute and chronic esophageal damage. QDOT catheter at 90W/4s leads to lower peak LETs, can lead to acute lesions but no chronic esophageal damage. LET can be used to monitor risk of esophageal damage in both HPSD protocols.

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

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.

Esophageal luminal temperature monitoring using a multi-sensor probe lowers the risk of esophageal injury in cryo and radiofrequency catheter ablation for atrial fibrillation.

Esophageal luminal temperature monitoring is a commonly used strategy to reduce esophageal thermal injury in catheter ablation for atrial fibrillation (AFib). We sought to compare the incidence of endoscopically detected esophageal lesions (EDEL) between two commonly used esophageal luminal temperature probes. Consecutive patients undergoing ablation with esophageal luminal temperature monitoring and upper endoscopy within 24h after ablation were included. Four hundred forty-five patients (64 ± 10years, 44% female) were included. Esophageal temperature monitoring was done with a single-sensor probe in 213 (48%) and multi-sensor probe in 232 (52%). Cryoballoon (CB) ablation was performed in 118 (27%) and radiofrequency (RF) ablation in 327 (73%) of patients. EDEL was present in 94 (22.9%) of which 85 were mild, 8 were moderate, and 1 was severe, and none progressed to atrial-esophageal fistula. The use of the multi-sensor probe during CB ablation was associated with a reduction in EDEL compared to single sensor (6.8% vs 24.3%; P = 0.016). Similarly, in the RF ablation group, EDEL was present in 19.5% of the multi-sensor group vs 32.8% in the single-sensor group (P = 0.001). Logistic regression showed that multi-sensor probe use was associated with reduction in EDEL with an odds ratio of 0.23 in CB ablation (P = 0.024) and 0.44 for RF ablation (P = 0.001). Esophageal luminal temperature monitoring during AFib ablation using a multi-sensor probe was associated with a significant reduction in EDEL compared to a single-sensor probe.

Improved 1-year outcomes after active cooling during left atrial radiofrequency ablation

BackgroundActive esophageal cooling during pulmonary vein isolation (PVI) with radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF) is increasingly being utilized to reduce esophageal injury and atrioesophageal fistula formation. Randomized controlled data also show trends towards increased freedom from AF when using active cooling. This study aimed to compare 1-year arrhythmia recurrence rates between patients treated with luminal esophageal temperature (LET) monitoring versus active esophageal cooling during left atrial ablation.MethodData from two healthcare systems (including 3 hospitals and 4 electrophysiologists) were reviewed for patient rhythm status at 1-year follow-up after receiving PVI for the treatment of AF. Results were compared between patients receiving active esophageal cooling (ensoETM, Attune Medical, Chicago, IL) and those treated with traditional LET monitoring using Kaplan–Meier estimates.ResultsA total of 513 patients were reviewed; 253 received LET monitoring using either single or multi-sensor temperature probes; and 260 received active cooling. The mean age was 66.8 (SD ± 10) years, and 36.8% were female. Arrhythmias were 60.1% paroxysmal AF, 34.3% persistent AF, and 5.6% long-standing persistent AF, with no significant difference between groups. At 1-year follow-up, KM estimates for freedom from AF were 58.2% for LET-monitored patients and 72.2% for actively cooled patients, for an absolute increase in freedom from AF of 14% with active esophageal cooling (p = .03). Adjustment for the confounders of patient age, gender, type of AF, and operator with an inverse probability of treatment weighted Cox proportional hazards model yielded a hazard ratio of 0.6 for the effect of cooling on AF recurrence (p = 0.045).ConclusionsIn this first study to date of the association between esophageal protection strategy and long-term efficacy of left atrial RF ablation, a clinically and statistically significant improvement in freedom from atrial arrhythmia at 1 year was found in patients treated with active esophageal cooling when compared to patients who received LET monitoring. More rigorous prospective studies or randomized studies are required to validate the findings of the current study.

Improved hospital discharge and cost savings with esophageal cooling during left atrial ablation

BackgroundLeft atrial ablation to obtain pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF) is a technologically intensive procedure utilizing innovative and continually improving technology. Changes in the technology utilized for PVI can in turn lead to changes in procedure costs. Because of the proximity of the esophagus to the posterior wall of the left atrium, various technologies have been utilized to protect against thermal injury during ablation. The impact on hospital costs during PVI ablation from utilization of different technologies for esophageal protection during ablation has not previously been evaluated.ObjectiveTo compare the costs of active esophageal cooling to luminal esophageal temperature (LET) monitoring during left atrial ablation.MethodsWe performed a time-driven activity-based costing (TDABC) analysis to determine costs for PVI procedures. Published data and literature review were utilized to determine differences in procedure time and same-day discharge rates using different esophageal protection technologies and to determine the cost impacts of same-day discharge versus overnight hospitalization after PVI procedures. The total costs were then compared between cases using active esophageal cooling to those using LET monitoring.ResultsThe effect of implementing active esophageal cooling was associated with up to a 24.7% reduction in mean total procedure time, and an 18% increase in same-day discharge rate. TDABC analysis identified a $681 reduction in procedure costs associated with the use of active esophageal cooling after including the cost of the esophageal cooling device. Factoring in the 18% increase in same-day discharge resulted in an increased cost savings of $2,135 per procedure.ConclusionsThe use of active esophageal cooling is associated with significant cost-savings when compared to traditional LET monitoring, even after accounting for the additional cost of the cooling device. These savings originate from a per-patient procedural time savings and a per-population improvement in same-day discharge rate.

Esophageal Protection and Temperature Monitoring Using the Circa S-Cath™ Temperature Probe during Epicardial Radiofrequency Ablation of the Pulmonary Veins and Posterior Left Atrium

Although epicardial bipolar radiofrequency ablation should diminish the risk of esophageal thermal injury in comparison to an endocardial ablation, cases of lethal atrio-esophageal fistula have been reported. To better understand this risk and to reduce the possibility of a thermal injury, we monitored the esophageal temperature with the Circa S-Cath™ temperature probe during and immediately after the ablation while implementing three procedural safety measures. Twenty patients (15 males; 63 ± 10 years) were prospectively enrolled (November 2019-February 2021). All patients underwent an epicardial ablation procedure, including an antral left and right pulmonary vein isolation with bidirectional bipolar clamping, and a roof and inferior line using unidirectional bipolar radiofrequency. Three procedural preventive mitigations were implemented: (1) transesophageal echocardiographic visualization of the atrio-esophageal interface, with probe retraction before the energy delivery; (2) lifting the ablated tissue away from the esophagus during an energy application; and (3) a 30 s cool-off and irrigation period after the energy delivery. The esophageal temperature was recorded using an insulated multisensory intraluminal esophageal temperature probe (Circa S-Cath™). Of the 20 patients enrolled, 7 patients had paroxysmal atrial fibrillation (AF), 8 persistent AF and 5 longstanding persistent AF. The average maximum luminal esophageal temperature observed was 36.2 ± 0.7 °C (34.8-38.2 °C). In our clinical experience, no abrupt increase in the luminal esophageal temperature above the baseline was observed. Since no measurements exceeded the threshold of 39 °C, no prompt interruption of energy delivery was required. Intraluminal esophageal temperature monitoring is feasible and can be helpful in confirming correct catheter position and safe energy application in bipolar epicardial left atrial ablation. Intra-procedural preventive mitigations should be implemented to reduce the risk of esophageal temperature rises.

Abstract 11284: Predicting Thermal Injury by Machine Learning Analysis of Luminal Esophageal Temperature Patterns in Atrial Fibrillation Ablation

Introduction: Luminal esophageal temperature (LET) monitoring during catheter ablation for atrial fibrillation (AF) is widely used to reduce the incidence of esophageal thermal injury (ETI). We sought to assess whether specific patterns of LET variation are associated with ETI. Methods: The CIRCA-S multi-sensor probe was used to record LET in AF patients undergoing radiofrequency (RFA) or cryoballoon ablation (CBA) ( Fig A ). Patients underwent upper endoscopy one day after ablation. LET data was analyzed for patterns associated with ETI ( Fig B ). A random forest classifier with 5x stratified cross validation was trained to predict ETI, and SHapley Additive exPlanations (SHAP) analysis was used to assess feature importance in the prediction of ETI. Results: A total of 90 patients (63% paroxysmal AF; 27% female) were included. Among them, 68 patients underwent RFA, and 22 patients CBA. ETI was detected in 11 patients (10 RFA and 1 CBA). In case of RFA, the highest LET recorded was similar between patients who had an ETI and those who did not (40.4 [39.1, 41] vs 40.6 [40.1, 41], p=0.4); however, the rate of LET rise for the highest recorded peak was higher (0.08 [0.03, 0.12] vs 0.02 [0.01, 0.05]; p=0.02) and area under the curve (AUC) for highest peak was smaller (412.5 [206.8, 634.1] vs 545.5 [369.9, 855.1]; p=0.066) in patients who had ETI. In case of CBA, the patient with ETI had a faster LET decline (0.12 vs 0.07 [0.02, 0.14]), and a smaller AUC for the lowest trough (2491.3 vs 2629.3 [1712.6, 5283.2]) compared to patients who had no ETI. SHAP analysis revealed that for the overall population, rate of LET change was the most important feature in the prediction of ETI ( Fig C ), and that a rate of LET change &gt;0.1°C/s is most predictive of ETI ( Fig D ). Conclusion: Rate of LET change and AUC for the recorded temperature are more important predictors of ETI compared to absolute peak temperatures. Prospective studies guided by these parameters are needed to demonstrate their efficacy in reducing ETI.