Esophageal Temperature Research Articles

PO-02-074 A META-ANALYSIS TO EVALUATE THE EFFICACY OF ESOPHAGEAL COOLING IN PREVENTING ESOPHAGEAL INJURY DURING RADIOFREQUENCY ABLATION

Esophageal injury during radiofrequency (RF) ablation of atrial fibrillation (AF) is a known complication. It could range from mild esophagitis to esophageal ulcers. Atrio-esophageal fistula (AEF) is the most dreaded complication. It is rare but potentially life-threatening. Various measures to reduce esophageal injury including esophageal temperature monitoring, reducing ablation power on the posterior wall and esophageal deviation have been used. Esophageal cooling during RF ablation has been used as a strategy to reduce esophageal injury. We performed a meta-analysis evaluating the efficacy of esophageal cooling during RF ablation in reducing esophageal injury. We performed a systematic literature review in Embase, PubMed and SCOPUS for all the related articles until December 2022. The literature search yielded 28 publications, of which 6 studies fulfilled inclusion criteria. The Mantel- Haenszel random effects model was used to calculate odds ratio (OR) and 95% confidence intervals (CI). Outcomes analyzed were all esophageal lesions, mild to moderate and severe esophageal lesions as determined by post-procedure endoscopy. Esophageal cooling was performed in 469 patient and no esophageal cooling was used in 195 patients. Esophageal cooling significantly reduced severe esophageal injuries (OR = 0.37, 95% CI [0.18-0.79], P=0.01). There was no significant difference between the treatment groups in total number of esophageal lesion (OR = 0.60, 95% CI [0.22-1.64], P=0.32) and mild to moderate lesions (OR = 1.48, 95% CI [0.48-4.51], P=0.49). Esophageal cooling during RF ablation in the left atrium reduces the incidence of severe esophageal lesions.

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-01-038 THE PREVALENCE AND CHARACTERISTICS OF THE ESOPHAGEAL THERMAL INJURY IN EXTENSIVE PULMONARY VEIN ISOLATION USING HIGH POWER-SHORT DURATION ABLATION STRATEGY

There is little knowledge regarding the impact of radiofrequency (RF) ablation on the esophageal area when using the high power-short duration (HPSD) strategy. The purpose of this study was to evaluate the prevalence and the characteristics of the esophageal thermal injury in extensive pulmonary vein isolation (extensive-PVI) using HPSD strategy. Eighty-five consecutive patients (age:67±9 year, male:63) undergoing index extensive-PVI followed by the esophagogastroscopy performed within 5 days after the procedure were studied. Fluoroscopic image of esophagography was registered on the CARTO3 system (Biosense Webster, Inc., CA, USA) using the CARTOUNIVU (Biosense Webster, Inc.) module to precisely determine the ablation sites, and RF applications were limited to the fixed 50W/5-second setting at the esophageal area without any use of esophageal temperature monitoring. Extensive-PVI including esophageal area was performed by the 50W RF applications, with the targeted interlesion distance of ≤6 mm, ablation index (AI) of 400 for the posterior wall, and contact force (CF) of 5-15g using Thermocool SmartTouch Surround Flow catheter (Biosense Webster, Inc). Esophagogastroscopy was performed 2±1 days after the procedure. In the esophageal area, a median number of RF applications was 8 per patient, application time was 5.1±1.2 seconds, CF was 8.9±2.8g, and AI was 300.9±28.0 per lesion. After the first encircling, additional RF application was required for the conduction gap on the esophageal area in 4.7% (4 of 85) of the patients. Sixteen patients (18.8%) developed esophageal thermal injury (esophageal erosion: 1 patient, gastric hypomotility: 15 patients). All patients with esophageal thermal injury were asymptomatic. Multivariate logistic regression analysis revealed that RF applications to the esophageal area positioned at the posterior wall of right pulmonary veins because of the central or right esophageal location was the independent predictor of the esophageal thermal injury (odds ratio: 7.92, 95% confidence interval: 1.15 to 54.49, p=0.035). Although asymptomatic esophageal thermal injury were not rare, extensive-PVI using HPSD with exclusive 50W/5-second applications on the esophagus could be performed with low risk of the esophageal mucosal injury while maintaining the durability of lesion. More careful RF applications may be required for the esophageal area positioned at the posterior wall of right pulmonary veins.

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.

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-452663-2 LEFT ATRIAL BOX ISOLATION GUIDED BY FORCE-POWER-TIME FORMULA (ABLATION INDEX): HIGH PREVALENCE OF EPICARDIAL CONDUCTION VIA SEPTOPULMONARY BUNDLE IN ATRIAL FIBRILLATION PATIENTS

Circumferential, continuous, transmural atrial lesions are desired to facilitate pulmonary vein (PV) isolation. However, atrial wall thickness around the PV is variable (5-6 mm in the superior/anterior segments and 2-4 mm in the inferior/posterior segments). Previous experimental studies have shown that radiofrequency (RF) lesion depth and diameter can be predicted by a logarithmic formula using contact force (CF), RF power and application time (Force-Power-Time Formula, Ablation Index, AI). The purpose of this study was to test the ability of AI guided ablation to achieve left atrial (LA) box isolation by a single RF encirclement and examine the location of residual conduction (gap) within the box in patients with atrial fibrillation (AF). In 42 patients with AF, LA box isolation was performed using a 7.5Fr CF catheter (ThermoCool SmartTouch SF, Biosense Webster) and CARTO system. Using RF power (35-40Watts) and CF (5-45g), a target AI value of 380-400 was used for posterior/inferior segments with an inter-lesion distance (ILD) of 4mm and a target AI value of 550-600 for anterior/superior/septal segments with an ILD of 6mm along the box circumference (Figure). RF was delivered until AI reached target values or terminated prematurely when esophageal temperature reached <38.5°C. After the first encirclement along the box line, activation mapping was performed to confirm box isolation and identify gap locations. Total RF time for box isolation was 27.2±4.6 min and box circumference length was 21.2±2.5 cm. Complete box isolation was obtained by the first encirclement in 17/42 (40%) pts. In the remaining 25/42 (60%) pts, activation mapping within the box lesion set identified earliest atrial activation along the ablation line in only 4/42 (10%) pts (indicating endocardial gaps), whereas activation mapping within the box identified earliest atrial activation at a site distant from the ablation line in 21/42 (50%) pts, suggesting epicardial conduction through a septopulmonary bundle (Figure). Focal ablation at endocardial gaps along the ablation line or at the epicardial focal breakouts within the box resulted in compete box isolation in all 25 pts. LA box isolation guided by AI effectively prevented endocardial gaps along the ablation line. However, epicardial conduction via a septopulmonary bundle was often observed (50%).

Efficacy and safety in patients treated with a novel radiofrequency balloon: a two centres experience from the AURORA collaboration.

A novel irrigated radiofrequency (RF) balloon (RFB) for pulmonary vein (PV) isolation (PVI) was released in selected centres. We pooled the procedural data on efficacy and safety of RFB-PVI from two high volume German centres. Consecutive patients with RFB procedures were enrolled. A 3D electroanatomical left atrial map guided the RFB navigation. Every RF delivery lasted 60 s, and duration was automatically reduced to 20 s for electrodes facing the posterior wall. Procedural data and post-procedural endoscopy data (<48 h) were analysed. Data from 140 patients were collected (57% male, 67 ± 11 years, 57% paroxysmal atrial fibrillation). There were 547 PVs identified, and 99.1% could be isolated using solely the RFB. Single-shot PVI was recorded in 330/547 (60%) PVs. Median time to isolation during the first application was 10 s (IQR 8-13). A total of 2.1 ± 1.8 applications per PV were delivered, with the left superior PV requiring more application compared to other PVs. Median procedure and fluoroscopy time were 77 min (61-99) and 13 min (10-17), respectively. Major safety events were recorded only in the first 25 cases at each centre and included 1/140(0.7%) cardiac tamponade, 1/140(0.7%) phrenic nerve palsy, and 2/140 strokes (1.4%). An oesophageal temperature rise was recorded in 81/547 (15%) PVs, and endoscopy detected oesophageal lesions in 7/85 (8%) patients undergoing endoscopy. The RFB showed a high efficacy allowing for fast PVI procedures, and 60% of PVs could be isolated at the first application. Most safety events were recorded during the learning phase. An oesophageal temperature monitoring is suggested: oesophageal lesions were detected in 8% of patients.

Zero-heat-flux thermometry over the carotid artery in assessment of core temperature in craniotomy patients

Zero-heat-flux core temperature measurements on the forehead (ZHF-forehead) show acceptable agreement with invasive core temperature measurements but are not always possible in general anesthesia. However, ZHF measurements over the carotid artery (ZHF-neck) have been shown reliable in cardiac surgery. We investigated these in non-cardiac surgery. In 99 craniotomy patients, we assessed agreement of ZHF-forehead and ZHF-neck (3M™ Bair Hugger™) with esophageal temperatures. We applied Bland-Altman analysis and calculated mean absolute differences (difference index) and proportion of differences within ± 0.5 °C (percentage index) during entire anesthesia and before and after esophageal temperature nadir. In Bland-Altman analysis [mean (limits of agreement)], agreement with esophageal temperature during entire anesthesia was 0.1 (−0.7 to +0.8) °C (ZHF-neck) and 0.0 (−0.8 to +0.8) °C (ZHF-forehead), and, after core temperature nadir, 0.1 (−0.5 to +0.7) °C and 0.1 (−0.6 to +0.8) °C, respectively. In difference index [median (interquartile range)], ZHF-neck and ZHF-forehead performed equally during entire anesthesia [ZHF-neck: 0.2 (0.1–0.3) °C vs ZHF-forehead: 0.2 (0.2–0.4) °C], and after core temperature nadir [0.2 (0.1–0.3) °C vs 0.2 (0.1–0.3) °C, respectively; all p > 0.017 after Bonferroni correction]. In percentage index [median (interquartile range)], both ZHF-neck [100 (92–100) %] and ZHF-forehead [100 (92–100) %] scored almost 100% after esophageal nadir. ZHF-neck measures core temperature as reliably as ZHF-forehead in non-cardiac surgery. ZHF-neck is an alternative to ZHF-forehead if the latter cannot be applied.

Relationship between perioperative cardiopulmonary bypass time, platelet count, fibrinogen level, rotational thromboelastometry data, antithrombin level, and blood loss volume and the effects of deep hypothermic circulatory arrest: An observational study.

We hypothesized that perioperative fibrinogen level, platelet count, and rotational thromboelastometry (ROTEM) data values decrease in proportion to cardiopulmonary bypass (CPB) time, particularly in patients who underwent deep hypothermic circulatory arrest (DHCA). A total of 160 patients were enrolled and divided into the following three groups depending on CPB time: <2-h, 2- 3-h, and >3-h groups. Blood samples were obtained during CPB weaning. Platelet count, ROTEM data, fibrinogen level, and antithrombin level were determined. For propensity matching, we selected 15 patients who underwent DHCA and 15 patients who did not undergo DHCA and used propensity scores to match CPB time and other characteristics. The <2-h, 2-3-h, and >3-h groups included 74, 63, and 23 patients, respectively. No significant differences in platelet count and fibrinogen level were observed between the groups. Antithrombin level and amplitude of clot firmness at 10min in the EXTEM and FIBTEM tests were lowest in the >3-h group. Similarly, blood loss volume and transfusion volume were highest in the >3-h group. Significant differences in platelet count, ROTEM data, lowest esophageal and bladder temperatures, and transfusion volume were observed between patients who underwent DHCA and patients who did not undergo DHCA. The longer the CPB time, the greater the perioperative blood loss volume and transfusion volume, particularly if CPB time is greater than 3hours. Sub-group analysis revealed that DHCA affects perioperative platelet count and function as well as blood loss volume.

Comparison of the LigaSure™ bipolar vessel sealer to monopolar electrocoagulation for thoracoscopic lobectomy and lymphadenectomy: a prospective randomized controlled trial

BackgroundHigh-energy devices allow better vessel sealing compared with monopolar electrocautery and could improve the outcomes of surgical operations. The objective of the study was to compare tissue dissection by the LigaSure™ device with that by monopolar electrocoagulation for thoracoscopic lobectomy and lymphadenectomy.MethodsThis pragmatic, parallel group, prospective randomized controlled trial was funded by the Medtronic External Research Program (ISR-2016–10,756) and registered at www.clinicaltrials.gov (NCT03125798). The study included patients aged 18 years or older, who had undergone thoracoscopic lobectomy with lymphadenectomy at the Department of Thoracic Surgery of Poznan University of Medical Sciences between May 3, 2018, and November 4, 2021. Using simple randomization, the patients were assigned to undergo tissue dissection with either the LigaSure device (study group) or monopolar electrocautery (control group). Participants and care givers, except operating surgeons, were blinded to group assignment. The primary outcome was postoperative chest drainage volume. Secondary outcomes were change of the esophageal temperature during subcarinal lymphadenectomy and C-reactive protein level 72 h after surgery.ResultsStudy outcomes were analyzed in 107 patients in each group. We found no differences between the study and control groups in terms of chest drainage volume (550 vs. 600 mL, respectively; p = 0.315), changes in esophageal temperature (− 0.1 °C vs. − 0.1 °C, respectively; p = 0.784), and C-reactive protein levels (72.8 vs. 70.8 mg/L, respectively; p = 0.503). The mean numbers of lymph nodes removed were 12.9 (SD: 3.1; 95% CI, 12.4 to 13.5) in the study group and 11.6 (SD: 3.2; 95% CI, 11.0 to 12.2) in the control group (p < 0.001).ConclusionsThe use of the LigaSure device did not allow to decrease the chest drainage volume, local thermal spread, and systemic inflammatory response. The number of lymph nodes removed was higher in patients operated with the LigaSure device, which indicated better quality of lymphadenectomy.

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.

Catheter ablation of atrial fibrillation with a multi-electrode radiofrequency balloon; first and early two centre experience in Europe.

The Heliostar™ ablation system is a novel RF balloon ablation technology with an integrated three-dimensional mapping system. Here, we describe our early experience and procedural outcomes using this technology for atrial fibrillation catheter ablation. We sought to comprehensively assess the first 60 consecutive patients undergoing pulmonary vein isolation using the novel HELISOTAR™ RF balloon technology including procedural outcomes. A comparison of the workflow between two different anaesthetic modalities (conscious sedation [CS] vs. general anaesthesia [GA]) was made. Procedural data were collected prospectively from two high-volume centers (Barts Heart Centre, UK and University Hospital of Zurich, Zurich). A standardized approach for catheter ablation was employed. A total of 35 patients had the procedure under CS and the remaining under GA. Mean procedural and fluoroscopy times were 84 ± 33 min and 1.1 min. The median duration of RF energy application was 7 (5-9.8) mins per patient. All veins were successfully isolated, and the median isolation time was 10 (7-15) seconds. Our cohort's rate of procedural complications was low, with no mortality within 30 days postprocedure. Our early experience shows that catheter ablation using the Heliostar™ technology can be performed efficiently and safely; however, long-term data is yet to be established. Low fluoroscopy requirements, short learning curves and use of this technology with CS is possible, including the use of an oesophageal temperature 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.

Pulmonary vein isolation-induced vagal nerve injury and gastric motility disorders detected by electrogastrography: The side effects of pulmonary vein isolation in atrial fibrillation (SEPIA) study.

Safety of pulmonary vein isolation (PVI) has been established in clinical studies. However, despite prevention efforts the incidence of damage to (peri)-esophageal tissue has not decreased, and the pathophysiology is incompletely understood. Damage to vagal nerve branches may be involved in lesion progression to atrio-esophageal fistula. Using electrogastrography, we assessed the incidence of periesophageal vagal nerve injury (VNI) following atrial fibrillation ablation and its association with procedural parameters and endoscopic results. Patients were studied using electrogastrography, endoscopy, and endoscopic ultrasound before and after cryoballoon (CB) or radiofrequency (RF) PVI. The incidence of ablation-induced neuropathic pattern (indicating VNI) in pre- and postprocedural electrogastrography was assessed and correlated with endoscopic results and ablation data. Between February 2021 und January 2022, 85 patients (67 ± 10 years, 53% male) were included, 33 were treated with CB and 52 with RF (38 with moderate power moderate duration [25-30 W] and 14 with high power short duration [50 W]). Ablation-induced VNI was detected in 27/85 patients independent of the energy form. Patients with VNI more frequently had postprocedural endoscopically detected pathology (8% mucosal esophageal lesions, 36% periesophageal edema, 33% food retention) but there was incomplete overlap. Pre-existing esophagitis increased the likelihood of VNI. Ablation data and esophageal temperature data did not predict VNI. PVI-induced VNI is quite common and independent of ablation energy source. VNI is part of (peri)-esophageal damage and only partially overlaps with endoscopic findings. VNI-associated acidic reflux may be involved in the complex pathophysiology of esophageal lesion progression to fistula.

A randomized crossover study of the effect of butorphanol-lidocaine and tramadol-lidocaine on sevoflurane's minimum alveolar concentration in dogs.

Inhalational anesthesia is routinely used in small animal surgery. Selecting a suitable drug combination is vital since it may negatively affect the patient's physiological condition. We conducted this study to examine the sparing effect of butorphanol-lidocaine (BUT-LID) and tramadol-lidocaine (TRM-LID) on sevoflurane's minimum alveolar concentration (MAC) in 10 healthy mongrel dogs aged 1-2 years and weighing 11.5 ± 0.8 kg (mean ± SD). Sevoflurane's MAC was measured on three separate occasions. The three dog treatment groups were control (CONT) anesthetized only with sevoflurane, TRM-LID (TRM, i.v. 1.5 mg kg-1, then 1.3 mg kg-1 h-1 and LID, i.v. 2 mg kg-1, then 3 mg kg-1 h-1) or BUT-LID treatment (BUT, i.v. 0.1 mg kg-1 then 0.2 mg kg-1 h-1 and LID, i.v. 2 mg kg-1, then 3 mg kg-1 h-1). We hypothesized that both TRM-LID and BUT-LID would result in a significant MAC sparing effect in healthy dogs. The TRM-LID treatment resulted in a non-significant MAC reduction. MAC was lowered significantly in the BUT-LID group (p = 0.009). The sevoflurane MAC-sparing effects of TRM-LID and BUT-LID treatments were 7.05 ± 22.20 and 19.90 ± 5.91%, respectively, a difference that was not statistically significant (p = 0.13). Bradycardia was observed in the TRM-LID (p < 0.001) treatment. The esophageal temperature was significantly higher for the TRM-LID treatment than the CONT (p < 0.001) treatment. No statistically significant changes were detected between the three groups in f R, Pe'CO2, and MABP. In conclusion, there was a significant sparing effect after adding BUT-LID co-infusion than the control group. No sparing effect was noticed when adding TRM-LID co-infusion. However, no difference in the MAC sparing percentages between the TRM-LID and BUT-LID treatments. The BUT-LID co-infusion resulted in a sevoflurane MAC reduction superior to TRM-LID in addition to minimal cardiorespiratory changes. Both BUT-LID and TRM-LID may be clinically beneficial to dogs during anesthesia. However, BUT-LID produced higher sparing effect and reduction of sevoflurane MAC value.

The impact of the procedural parameters on the lesion characteristics associated with AF recurrence: Late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) analysis.

Lesion gaps assessed by late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) are associated with the atrial fibrillation (AF) recurrence after pulmonary vein isolation. Animal studies have demonstrated that the catheter-contact force (CF), stability, and orientation are strongly associated with lesion formation. However, the impact of those procedural factors on the lesion characteristics associated with AF recurrence has not been well discussed. A total of 30 patients with paroxysmal AF who underwent catheter ablation were retrospectively enrolled. Radiofrequency (RF) applications were performed with 35 W for 30 s in a point-by-point fashion under esophageal temperature monitoring. The inter-lesion distance was 4 mm. The lesions were visualized by LGE-MRI 3 months postprocedure and assessed by the LGE volume (ml), gap number (GN), and average gap length (AGL [mm]). The gaps were defined as nonenhancement sites of >4 mm. The procedural factors including the catheter-CF, stability, and orientation were calculated on the NavX system. Six (20%) of 30 patients had AF recurrences 12 months postablation. A univariate analysis demonstrated that the AGL was associated with AF recurrence (hazard ratio [HR]: 1.20, confidence interval [CI]: 1.03-1.42, p = .02). All AF recurrence were found in patients with an AGL of >7 mm. The catheter-CF and stability were associated with an AGL of >7 mm, but not the orientation (CF-HR: 0.62, CI: 0.39-0.97, p = .038; stability-HR: 0.8, CI: 0.66-0.98, p = .027). RF ablation with a low CF and poor catheter stability has a potential risk of creating large lesion gaps associated with AF recurrence.

Impact of passive heat stress and passive heat acclimation on circulating extracellular vesicles: An exploratory analysis.

What is the central question of this study? How does passive heat stress and subsequent heat acclimation affect the circulating concentration of extracellular vesicles? What is the main finding and its importance? Passive heat stress increased the circulating concentration of total and platelet extracellular vesicles. Seven days of hot water immersion did not modify the change in circulating concentrations of extracellular vesicles during passive heat stress. This retrospective exploratory analysis aimed to improve our understanding of the effect of passive heat stress and subsequent heat acclimation on the circulating concentration of extracellular vesicles (EVs). Healthy young adults (four females and six males, 25±4 years of age, 1.72±0.08m in height and weighing 71.6±9.0kg) were heated with a water-perfused suit before and after seven consecutive days of hot water immersion. Pre-acclimation, participants were heated until oesophageal temperature increased to ∼1.4°C above baseline values. Post-acclimation, participants were heated until oesophageal temperature reached the same absolute value as the pre-acclimation visit (∼38.2°C). Venous blood samples were obtained before and at the end of passive heating to quantify plasma concentrations of EVs from all cell types (CSFE+ ), all cell types except erythrocytes (CSFE+ MHCI+ ), platelets (CSFE+ MHCI+ CD41+ ), endothelial cells (CSFE+ MHCI+ CD62e+ ), red blood cells (CSFE+ CD235a+ ) and leucocytes (CSFE+ MHCI+ CD45+ ) via flow cytometry. Passive heat stress increased the concentration of CFSE+ EVs (46,150,000/ml [3,620,784, 88,679,216], P=0.036), CFSE+ MHCI+ EVs (28,787,500/ml [9,851,127, 47,723,873], P=0.021) and CSFE+ MHCI+ CD41+ EVs (28,343,500/ml [9,637,432, 47,049,568], P=0.008). The concentration of CSFE+ MHCI+ CD62e+ EVs (94,230/ml [-55,099, 243,559], P=0.187), CSFE+ CD235a+ EVs (-1,414/ml [-15,709, 12,882], P=0.403) or CSFE+ MHCI+ CD45+ EVs (-192,915/ml [-690,166, 304,336], P=0.828) did not differ during heat stress. The change in circulating EVs during passive heat stress did not differ after heat acclimation (thermal state × acclimation interactions, all P≥0.180). These results demonstrate that passive heat stress increases the circulating concentration of total and platelet EVs and that passive heat acclimation does not alter this increase.

Accuracy of Nasopharyngeal Temperature in Comparison to Oesophageal Temperature for Core Body Temperature Measurement: A Cross-sectional Observational Study

Introduction: Temperature monitoring intraoperatively is standard of care for almost all surgical cases and is necessary due to the important role that temperature plays in maintaining body homeostasis, anaesthetic drug metabolism, and recovery. However, invasive and user-unfriendly methods like measuring temperature in the oesophagus, tympanic membrane, or rectum have limitations. An alternative site for measuring core body temperature could be the nasopharynx, as its mucosa is supplied by branches of the internal carotid artery. Aim: To determine the accuracy of the nasopharyngeal probe in comparison to oesophageal temperature probe and to identify appropriate insertion depths for measuring core body temperature. Materials and Methods: Sixty patients scheduled for elective non-cardiac surgery under general anaesthesia lasting 60 minutes or more. A nasopharyngeal probe was inserted past the nares to a depth of 20 cm, and an oesophageal temperature probe was inserted to a depth of 40 cm past the incisors. The nasopharyngeal probe was gradually pulled out after induction, and temperatures at various depths were recorded at regular intervals. The observed depths of the nasopharyngeal probe that correlated with the oesophageal temperature were considered as the endpoints. Data was entered into Microsoft Excel and analysed using Statistical Package for Social Sciences (SPSS) version 25.0. Results: The study population consisted of 60 patients, with 31 males and 29 females, a mean age of 50 years, mean body mass index of 26 kg/m2 , American Society of Anaesthesiologists (ASA) (physical status) of 1 (n=27) and 2 (n=33). The insertion depths of 10 to 20 cm for the nasopharyngeal probe showed a mean temperature difference of ±0.3°C compared to the reference oesophageal temperature. This difference fell within the clinically acceptable accuracy range of 0 to 0.3°C (temperature mean difference ±1.96 SD) for both probes. Conclusion: The nasopharyngeal probe offers a minimally invasive method for measuring body temperature and is easily accessible for probe placement. However, the optimal depth of insertion past the nares has not been well established. Based on the results, which showed that the mean temperature difference between the two probes fell within the specified accuracy range when the nasopharyngeal probe was inserted to a depth range of 10 to 20 cm from the nares, it is advisable to use this depth range for core body temperature measurement in non cardiac surgeries.

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.

Temperature Monitoring in the Intensive Care Unit

Close monitoring and management of temperature abnormalities are crucial in the critically ill to minimize the physiological and biochemical ill effects of extremes of temperature. In the intensive care unit, core temperature monitoring using either urinary, nasopharyngeal, or esophageal temperatures is recommended. One needs to be aware of the pitfalls and fallacies of other commonly used sites.