Luminal Esophageal Temperature Research Articles

Is it safe to monitor oesophageal temperature during AF ablation?

A 71-year-old man with paroxysmal atrial fibrillation underwent pulmonary vein isolation (PVI). Luminal oesophageal temperature (LET) was monitored throughout the procedure using a probe with three thermocouples ( Figure panel A). Luminal oesophageal temperature remained below 39°C except for a 40 s episode of 40.3°C. An oesophageal endoscopy carried out on the day after the …

Measuring luminal esophageal temperature during pulmonary vein isolation of atrial fibrillation

To investigate the luminal esophageal temperature (LET) at the time of delivery of energy for pulmonary vein isolation (PVI). This study included a total of 110 patients with atrial fibrillation who underwent their first PVI procedure in our laboratory between March 2010 and February 2011. The LET was monitored in all patients. We measured the number of times that LET reached the cut-off temperature, the time when LET reached the cut-off temperature, the maximum temperature (T max) of the LET, and the time to return to the original pre-energy delivery temperature once the delivery of energy was stopped. Seventy-eight patients reached the cut-off temperature. It took 6 s at the shortest time for the LET to reach the cut-off temperature, and 216.5 ± 102.9 s for the temperature to return to the level before the delivery of energy. Some patients experienced a transient drop in the LET (TDLET) just before energy delivery. Ablation at these sites always produced a rise to the LET cut-off temperature. TDLET was not observed at sites where the LET did not rise. Thus, the TDLET before the energy delivery was useful to distinguish a high risk of esophageal injury before delivery of energy. Sites with a TDLET before energy delivery should be ablated with great caution or, perhaps, not at all.

Abstract 17786: Presence of an Esophageal Temperature Probe During Pulmonary Vein Isolation: Is There an Increased Risk for Esophageal Lesion Development?

Background: Luminal esophageal temperature (LET) measurement is investigated as a tool to decrease risk of esophageal lesion formation during pulmonary vein isolation using radiofrequency (RF) current. However, recent evidence from duty-cycled phased RF ablation revealed a possible contributing role of the esophageal probe to lesion formation by direct tissue heating or interaction with the ablation device. Whether the presence of a LET probe may increase lesion formation during conventional irrigated RF ablation has not yet been investigated. Methods and Results: 62 patients (65% male, age 63±11 years, LA 44±10 mm) with drug-resistant atrial fibrillation underwent circumferential pulmonary vein isolation (PVI) using irrigated RF energy and a 3D-mapping system. A maximum power of 30 Watts was applied at the left atrial posterior wall (LAPW). In 30 patients a LET probe with 5 metal electrodes (3 thermistors) was placed in the esophagus and continuously adjusted to the level of the target pulmonary vein (group 1). LET measurement was observational only and no temperature cutoff was used. In the remaining 32 patients, no LET probe was placed (group 2). All patients underwent gastro-esophagoscopy 2±1 days after the procedure. The cumulative RF energy applied to the LAPW was 21368±9449 Joules (group 1) and 18092±8143 Joules (group 2, p=0,15). Esophageal lesions were found in 12 patients (40%) of group 1 (ulcerations: 4, erythema: 8), and 11 patients (34%) of group 2 (ulcerations: 5, erythema: 4); p=0,65. Lesions healed without clinical sequelae on proton pump inhibitor therapy in all patients. Within group 1, maximum LET in patients with and without lesions was 45,7±3,7 °C and 43,8±3,9 °C, respectively (p=0,20). Conclusion: The incidence of reversible esophageal lesions after circumferential PVI using irrigated RF energy was similar whether or not a temperature probe was present in the esophagus when no temperature cutoff was used.

Mechanical Esophageal Displacement During Catheter Ablation for Atrial Fibrillation

To determine the feasibility and safety of esophageal displacement during atrial fibrillation (AF) ablation, to prevent thermal injury. Patients undergoing AF ablation are at risk of esophageal thermal injury, which ranges from superficial ulceration, to gastroparesis, to the rare but catastrophic atrioesophageal fistula. A common approach to avoid damage is luminal esophageal temperature (LET) monitoring; however, (1) temperature rises mandate interruptions in energy delivery that interrupt workflow and potentially decrease procedural efficacy, and (2) esophageal fistulas have been reported even with LET monitoring. A cohort of 20 consecutive patients undergoing radiofrequency (RF) (16 patients) or laser balloon (4 patients) ablation of AF under general anesthesia. After barium instillation, the esophagus was deviated using an endotracheal stylet placed within a thoracic chest tube. LET monitoring was used during catheter ablation. Upper GI endoscopy was performed prior to discharge. At the pulmonary vein level, leftward deviation measured 2.8 ± 1.6 cm (range: 0.4-5.7) and rightward deviation 2.8 ± 1.8 cm (range: 0.5-4.9). The temperature rose to >38.5 °C in 3/20 (15%) patients. In these 3 patients, there was an average of 2 applications/patient that recorded temperatures >38.5 °C. No patient had a temperature rise > 40 °C. Endoscopy revealed no esophageal ulceration from thermal injury in 18/19 (95%) patients; the sole patient with a thermally mediated ulceration had an unusual esophageal diverticulum fully across the posterior left atrium. Twelve patients (63%) exhibited trauma related to instrumentation with no clinical sequelae. Mechanical esophageal deviation is feasible and allows for uninterrupted energy delivery along the posterior wall during catheter ablation of AF.

Luminal esophageal temperature rise and esophageal lesion formation following remote-controlled magnetic pulmonary vein isolation

Remote magnetic pulmonary vein isolation (PVI) demonstrates comparable success rate to manual ablation, but thermal effects on esophageal tissue remain undefined. The purpose of this study was to evaluate the potential thermal effects on esophageal tissue during remote magnetic wide-area circumferential pulmonary vein isolation (CPVI). Twenty-five patients (23 men, age 57 ± 10 years) in the magnetic navigation system (MNS) group and 25 control subjects (15 men, age 61 ± 12 years) with drug-refractory paroxysmal or persistent atrial fibrillation underwent CPVI. A magnetic 3.5-mm irrigated-tip catheter (NaviStar ThermoCool RMT, Biosense Webster) and a nonmagnetic 3.5-mm irrigated-tip catheter (NaviStar ThermoCool, Biosense Webster) were used in the MNS and control group, respectively. A temperature probe (SensiTherm, St. Jude Medical), containing 3 thermocouples was placed in close proximity to the ablation site monitoring luminal esophageal temperature (LET). LET changes did not guide therapy. Postprocedural esophagogastroduodenoscopy (EGD) was performed in all patients. Successful CPVI was achieved in all patients. No esophageal lesions, minimal lesions, or ulcerations were found in 16 of 25 (64%), 7 of 25 (28%), and 2 of 25 (8%) in the MNS group and in 14 of 25 (56%), 10 of 25 (40%), and 1 of 25 (4%) patients in the control group, respectively. No atrioesophageal fistula occurred. Mean maximum LET in the magnetic group was 43.7°C ± 3.7°C compared to 45.4°C ± 3.5°C in the manual control group (P = .09). Remote magnetic PVI is associated with significant rise in LET and development of thermal esophageal lesions. In the MNS group, higher LET recordings were more likely to cause esophageal injury, whereas this association was not seen in the manual group despite a tendency toward higher mean maximum LET recordings.

Luminal Esophageal Temperature Monitoring With a Deflectable Esophageal Temperature Probe and Intracardiac Echocardiography May Reduce Esophageal Injury During Atrial Fibrillation Ablation Procedures

Luminal esophageal temperature (LET) monitoring is one strategy to minimize esophageal injury during atrial fibrillation ablation procedures. However, esophageal ulceration and fistulas have been reported despite adequate LET monitoring. The objective of this study was to assess a novel approach to LET monitoring with a deflectable LET probe on the rate of esophageal injury in patients undergoing atrial fibrillation ablation. Forty-five consecutive patients undergoing an atrial fibrillation ablation procedure followed by esophageal endoscopy were included in this prospective observational pilot study. LET monitoring was performed with a 7F deflectable ablation catheter that was positioned as close as possible to the site of left atrial ablation using the deflectable component of the catheter guided by visualization of its position on intracardiac echocardiography. Ablation in the posterior left atrial was limited to 25 W and terminated when the LET increased 2°C from baseline. Endoscopy was performed 1 to 2 days after the procedure. All patients had at least 1 LET elevation >2°C necessitating cessation of ablation. Deflection of the LET probe was needed to accurately measure LET in 5% of patients when ablating near the left pulmonary veins, whereas deflection of the LET probe was necessary in 88% of patients when ablating near the right pulmonary veins. The average maximum increase in LET was 2.5±1.5°C. No patients had esophageal thermal injury on follow-up endoscopy. A strategy of optimal LET probe placement using a deflectable LET probe and intracardiac echocardiography guidance, combined with cessation of radiofrequency ablation with a 2°C rise in LET, may reduce esophageal thermal injury during left atrial ablation procedures.

Prevention of atrial–esophageal fistula after catheter ablation of atrial fibrillation

The formation of atrial-esophageal fistula after catheter ablation for atrial fibrillation is a rare but devastating complication with high mortality. Prevention is of utmost importance. We review the usefulness of currently available preventive measures. Recent studies using endoscopy after atrial fibrillation ablation show the development of esophageal ulcerations in 14-17% of the patients. Risk factors for the occurrence of esophageal ulcerations seem to be a high esophageal luminal temperature during ablation, increased power during energy application at the posterior left-atrial wall, a short left atrium-to-esophagus distance, the use of nasogastric tubes and general anesthesia. The main available tools for prevention of atrial-esophageal fistula include: 1) Assessment of the esophagus position in the preprocedural CT/MRI scan. Its usefulness is limited by the potential of the esophagus to move. 2) Tagging of the esophagus and real-time visualization of its course during the procedure. This can be achieved by introduction of a catheter into the esophagus and visualization in the three-dimensional electroanatomical system, by intracardiac ultrasound or by fluoroscopy. 3) Continuous monitoring of the esophageal luminal temperature during ablation with special temperature sensors. 4) Reduction of power during energy application at the posterior left-atrial wall in close proximity to the esophagus. Despite application of preventive measures, cases of atrial-esophageal fistulas have been reported. Several measures for prevention of atrial-esophageal fistula formation are available nowadays. Although these measures cannot completely eliminate the risk of fistula, it appears prudent to apply a combination of them during atrial fibrillation ablation.

Fatal course of esophageal stenting of an atrioesophageal fistula after atrial fibrillation ablation

Fatal course of esophageal stenting of an atrioesophageal fistula after atrial fibrillation ablation

Utility of Esophageal Temperature Monitoring During Pulmonary Vein Isolation for Atrial Fibrillation Using Duty-Cycled Phased Radiofrequency Ablation

A novel ablation system has been introduced for rapid treatment of atrial fibrillation (AF). This system delivers duty-cycled phased radiofrequency (RF) energy via an over-the-wire catheter (PVAC® , Medtronic) to achieve pulmonary vein (PV) isolation. Lower power and depth control suggests that collateral damage might be minimized. However, no studies have investigated the potential for thermal effect and damage to the esophagus. Ninety consecutive patients undergoing PV-isolation were evaluated. Group A (48 patients) had continuous luminal esophageal temperature (LET) monitoring using a temperature probe with 3 metal electrodes located in the vicinity of the targeted PV ostia. Ablation ceased when LET exceeded 40 °C. Only patients with LET ≥ 39 °C underwent endoscopic evaluation to assess esophageal damage. Group B (42 patients) excluded LET monitoring but all patients underwent endoscopy. In Group A, 27 (56%) patients showed LET ≥ 39 °C (mean LET 40.5 °C). Endoscopy revealed esophageal alterations in 5 (8%) (3 erythema and 2 intramural bleeding). One hundred eighty-nine out of 190 (99.5%) targeted PVs were successfully isolated, with 1 PV unsuccessful due to high LET. In Group B all 165 targeted PVs (100%) were successfully isolated. Endoscopy in Group 2 revealed no esophageal alterations. Using a duty-cycled, phased RF ablation system is safe and effective to isolate PVs. No Eso alteration was documented after ablation when LET was not monitored. This suggests that the LET probe may contribute to the thermal effect. Whether the documented increments in LET are due to direct tissue heating or possible interaction between the LET probe requires further investigation.

Esophageal Endoscopy Results After Pulmonary Vein Isolation Using the Single Big Cryoballoon Technique

Reversible esophageal thermal lesions after cryoballoon pulmonary vein isolation (CB-PVI) have been reported when using variable balloon sizes. The aim of this study was to investigate (1) the incidence of esophageal thermal lesions, and (2) esophageal temperature changes associated with CB-PVI using the single big cryoballoon technique. Thirty-eight patients with atrial fibrillation underwent successful CB-PVI using only the 28 mm cryoballoon. Luminal esophageal temperature (LET) was continuously monitored by 3 thermocouples. Fluoroscopic distance from cryoballoon to esophagus probe was retrospectively evaluated in RAO 30 degrees and LAO 40 degrees projections. All patients underwent postprocedural esophageal endoscopy. Average minimal LET was lower during freezing at inferior PVs, when compared to superior PVs: 35.4 +/- 0.9 (range: 32.6 to 37.4; RSPV); 31.5 +/- 7.5 (2.5 to 37.6; RIPV); 32.9 +/- 5.2 (8.5 to 36.5; LSPV); and 30.3 +/- 8.4 degrees C (-6 to 36.7 degrees C; LIPV); P = 0.001. We found steep temperature gradients over distance (1) from the cryoballoon center (LETs < 10 degrees C confined to a distance of < 15 mm in both RAO 30 degrees and LAO 40 degrees projections), and (2) along the esophagus long axis, underscoring the need for multiple measurement sites. None of the patients showed esophageal thermal lesions at endoscopy after 3 +/- 1 (range 1-7) days. No AEF occurred during a follow-up of 125 +/- 78 days. In a cohort of AF patients treated by the single big cryoballoon technique, CB-PVI was not associated with thermal esophageal lesions.

Intrapericardial balloon placement for prevention of collateral injury during catheter ablation of the left atrium in a porcine model

Catheter ablation of the left atrium (LA) is associated with potential collateral injury to surrounding structures, especially the esophagus and the right phrenic nerve (PN). The purpose of this study was to evaluate the efficacy and feasibility of intrapericardial balloon placement (IPBP) for the protection of collateral structures adjacent to the LA. Electroanatomic mapping was performed in porcine hearts using a transseptal endocardial approach in eight swine weighing 40-50 kg. An intrapericardial balloon was inflated in the oblique sinus, via percutaneous epicardial access, to displace the esophagus. Similarly, with the balloon positioned in the transverse sinus, IPBP was used to displace the right PN. Esophageal temperature was monitored while endocardial radiofrequency (RF) energy was delivered to the distal inferior PV. In all cases, balloon placement was successful with no significant effects on hemodynamic function. Balloon inflation increased the distance between the esophagus and posterior LA by 12.3 +/- 4.0 mm. IPBP significantly attenuated increases in luminal esophageal temperature during endocardial RF application (6.1 +/- 2.4 degrees C vs. 1.2 +/- 1.1 degrees C; P<.0001). High-output endocardial pacing from the right superior pulmonary vein ostium stimulated PN activity. After displacement of the right PN with IPBP, PN capture was abolished in 30 (91%) of 33 sites. These findings demonstrate that in an animal model, IPBP is feasible in the setting of catheter ablation procedures and has the potential to decrease the risk of collateral damage to the esophagus and PN during LA ablation.

The esophageal effects of cryoenergy during cryoablation for atrial fibrillation

Cryoenergy is being increasingly used for atrial fibrillation (AF) ablation, but the thermal effect of cryoenergy on the esophagus remains undefined. This study examines the esophageal effects of cryoenergy used during AF ablation. Catheter ablation was performed using a cryoballoon catheter in 67 AF patients (Cryoballoon group), and a spot cryocatheter to complete irrigated radiofrequency lesion sets at segments in close proximity to the esophagus in 7 AF patients (Cryo-Focal group). A temperature probe monitored the luminal esophageal temperature (LET) in all patients; LET changes did not guide therapy. Post-procedural endoscopy was performed on 35 of 67 (52%) Cryoballoon and all Cryo-Focal patients. Significant LET decreases (>1 degrees C) occurred in 62 of 67 (93%) Cryoballoon patients. LET continued to decrease after termination of cryoablation before recovering to normal. Temperature decreases were more pronounced during ablation at the inferior (3.1 degrees C) than superior pulmonary veins (1.5 degrees C); the lowest observed temperature was 0 degrees C. Post-procedural endoscopy showed esophageal ulcerations in 6 of 35 (17%) patients. There were no atrial-esophageal fistulas, and all ulcers had healed on follow-up endoscopy. Patients with and without ulceration differed with respect to mean LET nadir, cumulative LET decrease, and number of LETs <30 degrees C. In the Cryo-Focal group, 6 +/- 2 spot cryolesions per patient resulted in 1.3 +/- 1 LET decreases per patient, and an absolute nadir of 32.5 degrees C. Cryoballoon ablation can cause significant LET decreases, resulting in reversible esophageal ulcerations in 17% of patients. No ulcerations occurred with adjunctive spot cryoablation at regions near the esophagus during radiofrequency ablation procedures.

To the Editor, Comments on Esophageal Luminal Temperature Measurement During Radiofrequency Ablation of Left Atrium

To the Editor, Comments on Esophageal Luminal Temperature Measurement During Radiofrequency Ablation of Left Atrium

Esophageal Injury and Temperature Monitoring During Atrial Fibrillation Ablation

Background— It is common practice to empirically limit the radiofrequency (RF) power when ablating the posterior left atrium during atrial fibrillation ablation to avoid thermal injury to the esophagus. The objective of this study was to determine whether RF energy delivery limited by luminal esophageal temperature (LET) monitoring is associated with a reduction in esophageal injury compared with a strategy of RF power limitation alone. Methods and Results— Eighty-one consecutive patients who underwent atrial fibrillation ablation followed by esophageal endoscopy were included in this observational study. All patients underwent extraostial electric pulmonary vein isolation by using an electroanatomic mapping system and irrigated RF ablation. All RF applications on the posterior left atrium were limited to 35 W. A commercially available, single-thermocouple esophageal probe was used to monitor LET in a subset of patients (n=67). In these cases, applications were promptly interrupted when LET was ≥38.5�C; further applications were performed at reduced power to obtain a LET &lt;38.5�C. Esophageal endoscopy was performed 1 to 3 days after the procedure. Ablation-related esophageal ulcerations were identified in 9 of 81 (11%) patients. All patients were asymptomatic. Of these 81 patients, LET monitoring during ablation occurred in 67 (83%) of patients. Esophageal injury was observed more frequently (36% versus 6%, P &lt;0.006) in the group without LET monitoring. Conclusions— These data suggest that LET monitoring may be associated with a reduction in esophageal injury compared with power limitation alone.

Limitations of Esophageal Temperature-Monitoring to Prevent Esophageal Injury During Atrial Fibrillation Ablation

A number of complications have been associated with ablation of atrial fibrillation (AF), including arterial thrombo-embolism, pulmonary vein stenosis, phrenic nerve injury, and pericardial tamponade.1–4 Esophageal injury, manifested as esophageal perforation or left atrial-esophageal fistula, has been reported after catheter or surgical ablation of AF using radiofrequency (RF) current5–8 and catheter ablation using high-intensity focused ultrasound (HIFU).9 Left atrial-esophageal fistula usually is associated with a very high morbidity and mortality, including air embolism and sepsis. Article see p 162 Esophageal injury during RF ablation in the left atrium is thought to be thermal injury.10–12 In this issue of Circulation: Arrhythmia and Electrophysiology , Singh et al13 sought to determine whether the risk of esophageal injury would be reduced by measuring the luminal esophageal temperature (LET) during ablation and maintaining the LET below 38.5°C. The LET was measured using a 9Fr flexible temperature probe (with a single thermocouple) in the esophagus. The temperature probe was maneuvered in cranial-caudal direction to position the thermocouple close to the ablation catheter tip in the left atrium. We agree in principal with the authors’ conclusion that esophageal temperature-monitoring may reduce the risk of esophageal injury during AF ablation. An esophageal ulcer was observed by endoscopy 1 to 3 days postablation in 4 of 67 (6%) patients with LET-monitoring (and discontinuing RF application at LET ≥38.5°C) compared to 5 of 14 (36%) patients without LET-monitoring. Importantly, in patients with LET-monitoring, this study showed no significant difference between patients with and without an esophageal ulcer and the maximum LET during ablation or the number of RF applications producing an increase in LET to ≥38.5°C. …

Esophageal Injury and Temperature Monitoring During Atrial Fibrillation Ablation

It is common practice to empirically limit the radiofrequency (RF) power when ablating the posterior left atrium during atrial fibrillation ablation to avoid thermal injury to the esophagus. The objective of this study was to determine whether RF energy delivery limited by luminal esophageal temperature (LET) monitoring is associated with a reduction in esophageal injury compared with a strategy of RF power limitation alone. Eighty-one consecutive patients who underwent atrial fibrillation ablation followed by esophageal endoscopy were included in this observational study. All patients underwent extraostial electric pulmonary vein isolation by using an electroanatomic mapping system and irrigated RF ablation. All RF applications on the posterior left atrium were limited to 35 W. A commercially available, single-thermocouple esophageal probe was used to monitor LET in a subset of patients (n=67). In these cases, applications were promptly interrupted when LET was > or =38.5 degrees C; further applications were performed at reduced power to obtain a LET < 38.5 degrees C. Esophageal endoscopy was performed 1 to 3 days after the procedure. Ablation-related esophageal ulcerations were identified in 9 of 81 (11%) patients. All patients were asymptomatic. Of these 81 patients, LET monitoring during ablation occurred in 67 (83%) of patients. Esophageal injury was observed more frequently (36% versus 6%, P<0.006) in the group without LET monitoring. These data suggest that LET monitoring may be associated with a reduction in esophageal injury compared with power limitation alone.

Esophageal Luminal Temperature Measurement Underestimates Esophageal Tissue Temperature During Radiofrequency Ablation Within the Canine Left Atrium: Comparison Between 8 mm Tip and Open Irrigation Catheters

Evaluation of luminal temperature during left atrial ablation is used clinically; however, luminal temperature does not necessarily reflect temperature within the esophageal wall and poses a risk of atrioesophageal fistula. This animal study evaluates luminal esophageal temperature and its relation to the temperature of the external esophageal tissue during left atrial lesions using the 8 mm solid tip and the open irrigated tip catheters (OIC). A thermocouple was secured to the external surface of the esophagus at the level of the left atrium of the dogs. Luminal esophageal temperature was measured using a standard temperature probe. In four randomized dogs, lesions were placed using an 8 mm solid tip ablation catheter. In six randomized dogs, lesions were placed using the 3.5 mm OIC. The average peak esophageal tissue temperature when using the OIC was significantly higher than that of the 8 mm tip catheter (88.6 degrees C +/- 15.0 degrees C vs. 62.3 degrees C +/- 12.5 degrees C, P < 0.05). Both OIC and 8 mm tip catheter had significantly higher peak tissue temperatures than luminal temperatures (OIC: 88.6 degrees C +/- 15.0 degrees C vs 39.7 degrees C +/- 0.82 degrees C, P < 0.05) (8 mm: 62.3 degrees C +/- 12.5 degrees C vs 39.0 +/- 0.5 degrees C, P < 0.05). Both catheters achieved peak temperatures faster in the tissue as compared to the lumen of the esophagus, although the tissue temperature peaked significantly faster for the OIC (OIC: 25 seconds vs 90 seconds, P < 0.05) (8 mm: 63 seconds vs 105 seconds, P < 0.05). Despite the significant difference in actual tissue temperatures, no significant difference was observed in luminal temperatures between the OIC and 8 mm tip catheter.

Atrial Fibrillation Ablation with Esophageal Cooling with a Cooled Water‐Irrigated Intraesophageal Balloon: A Pilot Study

A left atrioesophageal fistula is an uncommon but devastating complication that may occur during atrial fibrillation (AF) ablation, and may be due to thermal injury occurring during the radiofrequency (RF) ablation. We examined the feasibility of an esophageal cooling (ECO) method using a cooled water-irrigated intraesophageal balloon (IB). Eight patients with drug-refractory AF underwent RF catheter ablation to encircle the ipsilateral pulmonary veins. During the RF ablation at the posterior left atrium, the esophageal lumen was cooled using a 9-Fr. IB catheter with a balloon length of 40 mm and diameter of 10 mm, in which cooled water, with a water temperature of 4.5 +/- 3.1 degrees C, was irrigated while the luminal esophageal temperature (LET) was measured with an intraesophageal probe placed at a site close to the tip of the ablation catheter. In the control, the LET increased from 36.4 +/- 0.8 degrees C to 40.5 +/- 1.7 degrees C within 26.1 +/- 8.2 seconds during 3.9 +/- 1.2 RF energy applications, whereas with the ECO the LET decreased to 30.2 +/- 2.9 degrees C at baseline (P<0.01 vs control), and increased only to 33.5 +/- 2.9 degrees C (P<0.01 vs control) at most, within 30 seconds during 3.9 +/- 1.2 RF energy applications. All pulmonary veins were successfully isolated in all patients without any complications. During a follow-up period of 3.1 +/- 1.2 months, no esophageal injuries were observed and all but one patient have been free from any symptoms. Use of an IB successfully lowers LET. This might have the potential of preventing esophageal injury, although further study is required.

Real‐Time Monitoring of Luminal Esophageal Temperature During Left Atrial Radiofrequency Catheter Ablation for Atrial Fibrillation: Observations About Esophageal Heating During Ablation at the Pulmonary Vein Ostia and Posterior Left Atrium

Left atrial radiofrequency catheter ablation (RFA) is gaining acceptance as treatment for drug-refractory atrial fibrillation (AF). This therapy has been associated with esophageal injury and atrioesophageal fistula formation causing death. We describe 3 patients undergoing catheter ablation for AF during real-time monitoring of luminal esophageal temperature. We observed heating of the esophagus during short duration low power RFA, at either the left or right pulmonary vein ostia. Cryoablation at the pulmonary vein ostium in one patient resulted in esophageal cooling. Furthermore, we observed that fluoroscopic localization of the ablation catheter at a site apparently distant from the esophagus is not adequate to assure avoidance of ablation-induced esophageal heating. Real-time monitoring of luminal esophageal position and temperature is feasible, enhances recognition of esophageal heating, and may add useful information beyond that provided by fluoroscopic assessment of esophageal position. There is a potential role for esophageal monitoring to help avoid thermal injury to the esophagus during catheter ablation for atrial fibrillation.

Radiofrequency catheter ablation for atrial fibrillation produces delayed and long lasting elevation of luminal esophageal temperature independent of lesion duration and power

Radiofrequency catheter ablation for atrial fibrillation produces delayed and long lasting elevation of luminal esophageal temperature independent of lesion duration and power