Author + information
- Received September 6, 2016
- Revision received February 27, 2017
- Accepted March 5, 2017
- Published online August 30, 2017.
- Chandrasekar Palaniswamy, MD,
- Jacob S. Koruth, MD,
- Alexander J. Mittnacht, MD,
- Marc A. Miller, MD,
- Subbarao Choudry, MD,
- Rahul Bhardwaj, MD,
- Dinesh Sharma, MD,
- Jonathan M. Willner, MD,
- Sujata S. Balulad, MD,
- Elizabeth Verghese, MD,
- Georgios Syros, MD,
- Anurag Singh, MD,
- Srinivas R. Dukkipati, MD, FHRS and
- Vivek Y. Reddy, MD∗ ()
- ↵∗Address for correspondence:
Dr. Vivek Y. Reddy, Helmsley Electrophysiology Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, New York 10029.
Objectives This study sought to determine the extent of lateral esophageal displacement required during mechanical esophageal deviation (MED) and to eliminate luminal esophageal temperature elevation (LETElev) during pulmonary vein (PV) isolation.
Background MED is a conceptually attractive strategy of minimizing esophageal injury while allowing uninterrupted energy delivery along the posterior left atrium during PV isolation.
Methods MED was performed using a malleable metal stylet within a plastic tube placed within the esophagus. Barium was instilled to characterize the trailing esophageal edge. For each MED attempt, the MEDEffective, defined as the distance from the trailing esophageal edge-to-ablation line, was correlated to occurrences of LETElev.
Results In 114 consecutive patients/221 PV pairs undergoing MED (age 62.1 ± 11 years, 75% men, 62%/38% paroxysmal/persistent AF), esophageal stretching invariably occurred such that the esophageal edge trailed behind the plastic tube. MEDEffective distances of 0 mm to 10 mm, 10 mm to 15 mm, 15 mm to 20 mm or >20 mm were achieved in 60 (27.1%), 64 (29%), 48 (21.7%), and 49 (22.2%) attempts, respectively. Overall, LET elevation >38°C occurred in 81 of 221 (36.7%) PV pairs. The incidence of LETElev among the 4 groups was 73.3%, 35.9%, 25%, and 4.1%, respectively. MEDEffective distances were 9.1 ± 6.5 mm and 18 ± 7.6 mm in patients with and without LETElev, respectively (p < 0.0001). Three patients (2.6%) experienced clinically significant MED-related trauma, albeit only with a stiffer stylet.
Conclusions Mechanical esophageal deviation >20 mm from the PV ablation line prevents significant esophageal heating during PV isolation, but this level of displacement was difficult to safely achieve with this off-the-shelf mechanical stylet approach.
Catheter ablation has emerged as an effective and widely adopted treatment strategy for patients with symptomatic atrial fibrillation (AF). The procedure consists of pulmonary vein (PV) isolation alone or in combination with other lesion sets, predominantly in the left atrium (LA). Although it is safe overall when performed by experienced operators, the procedure is nonetheless associated with a small but significant risk of injury to collateral structures. Foremost among these is the esophagus, which lies in close proximity to the posterior LA and, in particular, the PV antrum, making it susceptible to ablation-related injury. Thermal injury to the esophagus resulting in atrioesophageal fistula remains one of the most feared complications of AF ablation. Despite increased awareness in the electrophysiology and cardiology communities of the signs and symptoms associated with post-ablation atrioesophageal fistula, and despite prompt diagnosis and treatment of the condition, the mortality of atrioesophageal fistula remains 55% (1). Beyond the fatal, but relatively rare, complication of atrioesophageal fistula, thermal damage to the vagus nerve plexus on the outside surface of the esophagus is thought to also lead to esophageal and gastric dysmotility issues such as gastroparesis (2). Recent data have emerged that these dysmotility issues are more common that previously appreciated, affecting 17% of patients after AF ablation (3).
There is no universally accepted approach for minimizing thermal injury to the esophagus. Many physicians use a strategy of monitoring the luminal esophageal temperature (LET) to identify esophageal heating during energy delivery. Radiofrequency (RF) energy is typically interrupted for an LET of 38° to 39°; however, this approach negatively affects procedural workflow because cessation of energy delivery (upon esophageal heating) must be followed by a waiting period before the esophageal temperature returns to baseline to allow subsequent lesions. Other strategies to minimize esophageal injury include: delivery of lower energy (usually ≤25 W), lesions of shorter duration, and planning more medial or lateral ablation sets on the posterior wall to minimize esophageal heating. However, these approaches may also negatively affect the long-term PV isolation rates and clinical success of the ablation procedure. Furthermore, none of these techniques completely avoids esophageal heating leading to atrioesophageal fistula and dysmotility. Esophageal cooling using a cooled water-irrigated esophageal balloon has also been described as a strategy to minimize thermal injury. Real-time visualization of the esophagus with intracardiac echocardiography, especially with the probe deployed in the LA, may also be used as a monitoring strategy to reduce esophageal injury.
Alternatively, we had previously reported the feasibility of mechanical esophageal deviation (MED) using an off-the-shelf malleable metal stylet delivered within a plastic tube to deviate the esophagus during AF ablation as a means to completely avoid esophageal injury (4). MED is an attractive strategy because esophageal injury could potentially be completely avoided while nonetheless allowing uninterrupted energy delivery along the posterior LA. Significant esophageal stretching may occur during MED such that the trailing esophageal edge may yet be in proximity to the thermal wave front emanating from the point of RF energy delivery. We sought to determine the extent of effective lateral esophageal displacement during MED (MEDEffective, defined as the distance from the trailing esophageal edge-to-ablation line), and correlate this with elevations of the esophageal temperature.
Consecutive patients undergoing AF ablation procedures using an approved RF ablation catheter from November 2014 to October 2015 at our institution were studied. The study was approved by the Institutional Review Board of Mount Sinai Hospital. Patients were excluded if they had a prior history of severe esophagitis or ulcers, strictures, or esophageal surgery. Patients undergoing repeat ablation procedures where the PVs were persistently isolated from prior procedures were also excluded. All patients underwent ablation under general anesthesia with a strategy of uninterrupted oral anticoagulation with either warfarin or a non-warfarin oral anticoagulant. Double transseptal punctures were performed after intravenous unfractionated heparin was administered to maintain an activated clotting time of 350 to 400 seconds.
Mechanical esophageal deviation technique
MED was performed after approval by the Mount Sinai Hospital “Novel Procedures Oversight Committee”; in addition to the standard consent for AF ablation, all patients were separately consented for MED. MED was performed after transseptal puncture and before creation of LA geometry with the electroanatomic mapping system. This was performed by anesthesiologists or electrophysiologists with prior experience in MED during our earlier study (4). As previously described, a standard orogastric tube was inserted. The tip was positioned at the distal end of the esophagus, and 20 to 30 ml of oral barium sulfate contrast (Liquid E-Z-Paque, E-Z-EM Canada Inc., Lake Success, New York) was injected to allow the contrast to fill the mid and distal esophagus. Instillation of barium helped accurately characterize the trailing edge of the esophagus. Next, a 32 Fr flexible polyvinyl chloride thoracic catheter (e.g., Atrium Medical Corporation, Hudson, New Hampshire) was inserted into the esophagus. The tip was positioned a few centimeters below the level of the lower PVs. A preshaped malleable metal stylet was inserted into the lumen of the thoracic catheter to create a curve in the distal half. In this series, there were 2 versions of metal stylets used: most commonly, a 14 Fr aluminum intubation stylet (stylet 1), and infrequently, a somewhat stiffer stylet made of stainless steel, the Gliderite rigid stylet (Verathon Inc., Bothell, Washington) that is designed to work with Glidescope video laryngoscopes (stylet 2). With either stylet, the proximal end was manipulated (applying clockwise/counterclockwise torque) to laterally displace the esophagus. Initially, stylet 1 was employed for deviation, but if the level of lateral excursion was insufficient, the stiffer stylet 2 was used. However, because of trauma to the oropharynx (see Results), this stiffer stylet was only employed in 4 patients and thereafter abandoned.
Methodology for assessing esophageal deviation
After MED, the LA geometry was created using an electroanatomic mapping system and PV isolation was performed. MED can lead to distortion of the anatomy and affect the accuracy of the electroanatomic map. MED was therefore maintained at the same level throughout the ablation along a PV pair to minimize these effects. After ipsilateral PV isolation with MED, repeat MED was performed to enable contralateral PV isolation. The electroanatomic map was always checked for accuracy and reconstructed if necessary in case of map shifts. LET was monitored using the S-CATH esophageal temperature monitoring probe (Circa Scientific Inc., Englewood, Colorado). The temperature probe was manipulated to ensure that it was positioned lateral to the thoracic tube at the trailing edge (Figure 1A). RF energy delivery on the posterior wall was terminated if LET exceeded 38°C; this was defined as an instance of LET elevation (LETElev). The peak LET was recorded for all temperature rises. Using fluoroscopy in the anteroposterior view, reference points were placed on the electroanatomical map corresponding to the trailing esophageal edge (Figure 1B). The extent of MEDEffective was defined as the distance between the PV isolation ablation line and the esophageal reference points corresponding to the trailing esophageal edge. Measurements were made using the tools available on each of the mapping systems employed.
For patients in whom the esophageal position at baseline was midline in reference to the PV antra, MED was performed to the side contralateral to the PV isolation set (for example, rightward deviation during ablation of the left PVs; Figure 2A). The esophagus was then deviated to the contralateral side; if there was a significant displacement of the atrial anatomy, the LA geometry was created again before ablation of the contralateral PVs (Figure 2B). In some instances where the baseline esophageal position was not midline and substantially toward one of the PV antra, further extreme deviation was performed to the same side to allow isolation of both PV pairs in that single deviated position (Figure 3A and 3B). The ease of placement of the device and deviation as reported by the operator were recorded on a Likert scale between 1 and 5, with 1 being easy and 5 being extremely difficult. Throat discomfort and dysphagia post-MED as reported by the patient were also recorded on a scale from 1 to 5. Any complications such as oral or pharyngeal bleeding, reintubation, fever, upper gastrointestinal bleed, or any other unexpected events were recorded.
Pulmonary vein isolation
Catheter mapping and manipulation was guided by either the Carto 3 (Biosense-Webster Inc., Diamond Bar, California) or NAVEX (St. Jude Medical Inc., Minneapolis, Minnesota) electroanatomical mapping system. Catheter ablation was performed using a force-sensing irrigated RF ablation catheter: either the Thermocool Smartouch (Biosense-Webster Inc.) or Tacticath (St. Jude Medical Inc.) ablation catheter. The power used during ablation along the posterior left atrium was not different than that used at other locations: typically, 35 to 40 W with the Smartouch catheter and 25 to 30 W with the Tacticath catheter.
Statistical analysis was performed using SAS system software, version 9.3 (SAS Institute Inc., Cary, North Carolina). Categorical variables are expressed as percentage and continuous variables as mean ± standard deviation. Categorical variables were analyzed using the chi-square or Fisher exact test; for continuous variables within a patient, such as MED distances, the paired Student t test was used. We used a 2-sided p value <0.05 to assess for statistical significance for all analyses. For the discrete outcomes that could not be assumed to be independent measurements (i.e., left/right readings per patient), such as the incidence of total temperature rises and MED >20 mm, generalized estimating equations (PROC GENMOD, SAS) was used. This linear regression technique corrects for the correlation among observations on the same individual by estimating the covariance structure of the data, thereby allowing for improved estimates of the standard errors of measurement.
Baseline characteristics of our study population are summarized in Table 1. The population included 114 patients (221 PV pairs: 112 right PVs and 109 left PVs) with paroxysmal AF (62%) or persistent AF (38%). The mean age was 62.1 ± 11 years, and 75% of patients were men. The median congenital heart failure, hypertension, age >75 years, diabetes mellitus, stroke, vascular disease, age 65 to 74 years, and sex score was 2. The ablation procedure was performed with uninterrupted anticoagulation in all patients: 20 (17.5%) with uninterrupted warfarin and the remaining 94 (82.5%) with uninterrupted non-warfarin oral anticoagulants. Antiplatelet therapy was being administered in 19 patients (16.7%). The procedure was the first-ever AF ablation procedure in 103 patients (90.4%) and a redo procedure in the remaining 11 patients (9.6%).
In Table 2, the procedural characteristics of the study cohort are described. Force-sensing irrigated ablation catheters were used in all procedures; approximately two-thirds of the procedures were performed using the Carto 3 system and the remaining one-third using the NavX system. PV isolation alone or in combination with cavotricuspid isthmus ablation was performed in 94.7% of patients. Additional linear lesions were placed in only 5.3% of patients. The mean fluoroscopy time was 21.6 ± 10.4 min and fluoroscopy dosage (air kerma) was 83 ± 48 mGy.
Mechanical esophageal deviation
Of the 114 patients, 7 (6.1%) had only 1 PV pair ablated, hence MED was performed on 1 side only. Of the remaining 107 patients, 96 underwent esophageal deviation to both sides, whereas 11 (10.3%) underwent extreme deviation to 1 side only. Of these 11 patients, 9 had an initial esophageal position that was leftward; the esophagus was further deviated to the extreme left side, and ablation of both PV pairs was performed in this position. The 1 remaining patients underwent extreme deviation to the right side, and both PV isolation lesion sets were placed. Qualitatively, it was invariably true that MED was associated with a significant trailing esophageal edge that would not have been appreciated without the use of either barium instillation to opacify the esophageal lumen or the careful placement of the esophageal temperature probe along the trailing edge.
Extent of MEDEffective
Based on the extent of MEDEffective as measured by the distance between the trailing esophageal edge and ablation lesion set, the instances of MED were stratified into 4 groups (Table 3). The extent of MEDEffective was 0 mm to 10 mm, 10 mm to 15 mm, 15 mm to 20 mm, or >20 mm in 60 (27.1%), 64 (29%), 48 (21.7%), and 49 (22.2%) instances of MED, respectively. Not surprisingly, the mean MEDEffective distances were 9.1 ± 6.5 mm and 18 ± 7.6 mm in patients with and without LETElev, respectively (p < 0.0001). Instances of LETElev among the 4 groups occurred in 73.3%, 35.9%, 25%, and 4.1% instances, respectively. Thus, a MEDEffective >20 mm largely eliminated LETElev; however, this was achieved in only 22.2% of patients, and was greater during ablation of the right PVs with leftward deviation than during ablation of the left PVs with rightward deviation (32.1% vs. 11.9%, p = 0.0006). Indeed, the average extent of MEDEffective achieved was greater for leftward deviation than for rightward deviation (17.4 ± 8.3 vs. 12.2 ± 7.3, p < 0.0001).
Similarly, although instances of LETElev occurred during ablation of 81/221(36.7%) PV pairs, there was a marked variation in the incidence of LETElev between the 2 directions of deviation: LETElev occurred during 25% cases of leftward deviation for right PVs ablation, but approximately doubled to 48.6% of cases during rightward deviation for left PVs ablation (Table 3). In total, there were 316 ablation lesions that resulted in LETElev during the 221 PV isolating lesion sets, translating to 1.4 ablations with LETElev per ipsilateral lesion set. Again, the incidence of LETElev/patient was higher for left PVs ablation with rightward deviation than right PVs ablation with leftward deviation (2.0 vs. 0.9 ablations/patient, respectively; p = 0.01).
Subjective assessment and complications
As summarized in Table 4, from a subjective perspective, the MED device was easy to place in the esophagus (mean score of 1.4 on Likert scale), but the actual deviation step was occasionally more difficult (mean score of 1.9 on Likert scale). On average, the patients experienced minimal throat pain or discomfort or dysphagia (mean scores of 1.3 and 1.2, respectively). Three patients did develop clinically significant oropharyngeal discomfort as a result of MED-related trauma. But in each of these cases, the stiffer stylet 2 had been used and the trauma occurred not in the esophagus (all of these patients underwent endoscopy), but rather the oropharynx. One patient experienced bleeding from a pharyngeal laceration that required cauterization. Two other patients sustained uvular hematoma that resolved spontaneously. All patients were followed clinically and none experienced any long-term sequelae. No cases of fever, upper gastrointestinal bleed, or any other unexpected events were noted. With use of the more malleable stylet 1, there was no evidence of symptomatic MED-related trauma. There were also no instances of atrioesophageal fistula or symptomatic gastric dysmotility.
In this study, we present the feasibility of mechanical esophageal deviation using an off-the-shelf malleable metal stylet during AF ablation in a large consecutive patient cohort, with specific attention to the relationship between the extent of esophageal excursion and LET rises (4). The major findings of this manuscript are that 1) lateral displacement of the esophagus is feasible in a diverse cohort of patients undergoing AF ablation, 2) it is necessary to deviate the esophagus ≥20 mm from the site of ablation to optimally eliminate esophageal heating, and 3) this optimal level of esophageal deviation can be achieved in only a minority of patients using this off-the-shelf stylet.
In a nonrandomized study, we had previously demonstrated that posterior LA ablation guided by LET monitoring (interruption of RF for temperature ≥38.5°C) was associated with a lower incidence of esophageal injury (6% vs 36%, p < 0.006) (5). This study was based on the concept that the LET probes, by virtue of their intraluminal location, can predict esophageal thermal injury by detecting LET rises, providing operators with an opportunity to interrupt or modify RF applications. Despite the positive outcome of this and other similar studies and the widespread adoption of LET monitoring by many operators, LET use does not universally prevent esophageal injury (6). This was recognized in several reports of esophageal injury despite LET monitoring. Several potential explanations can explain this paradox: 1) suboptimal selection of LET cutoffs that trigger RF interruption and 2) failure of the LET probe to sufficiently interrogate that lateralized portion of esophagus that is in closest proximity to the thermal source with the consequence of underdetection of thermal injury (7). The latter can occur either because the operator underestimates the proximity of the thermal source to the esophagus because of the inability to accurately visualize esophageal borders or because of design limitations of the LET probe itself (e.g., linear probes with single thermocouples have narrow sensing capability).
The LET probe in this study was chosen to address these limitations; specifically, by virtue of its width and multiple thermocouples, this probe is able to interrogate a much larger extent of the esophagus. In addition, we used real-time imaging of the esophagus with barium contrast to maximize the approximation of the LET probe with the borders of the esophagus. When combined with MED, this approach further improves the sensitivity of LET rises as a marker of esophageal injury. Although we did not perform routine endoscopy, the lack of LET rises in the setting of optimal MED provides the physician confidence that the esophagus is not being heated during uninterrupted posterior LA ablation. It is also of significance that power titration along the posterior LA was not modified; that is, the same amount of energy used anteriorly was also used posteriorly (except in instances of esophageal heating, in which case the power was down-titrated).
In this report, we also defined the concept of the trailing edge, its importance, and the extent of deviation necessary to avoid LET rises. Our experience clearly demonstrated that esophageal stretching occurs during MED, therefore highlighting the importance of identifying the trailing edge with either barium or the LET probe (provided the probe is truly placed at the trailing edge). If the trailing edge is not identified and the operator were to assume that the esophagus was sufficiently deviated based on the location the deviation tool along the “leading edge,” inadvertent delivery of RF energy to the esophagus may occur.
Finally, our results indicate that achieving deviation of 20 mm or more results in infrequent LET rises. This is consistent with a previous study of 106 consecutive AF ablation patients in which the authors demonstrated that LET elevation was more frequent with a lesser degree of separation between the esophagus and ablation sites along the posterior LA. They also described that at separations ≥20 mm, LET rises (>38°C) never occurred (8). Our results are consistent with the results of this study. On the other hand, in our study, this ideal degree esophageal deviation was achievable in only 22% of patients. This appears to be driven in part by the limitations of the technique used for deviation in this report in that the tool itself typically used, stylet 1, was unable to achieve sufficient lateral displacement of the esophagus in all patients. Interestingly, it was our qualitative impression that a greater extent of lateral excursion was achieved with the stiffer stylet 2; however, this stylet resulted in oropharyngeal trauma; indeed, 3 of the 4 patients in whom this was used experienced clinically significant trauma. Thus, there was a tradeoff between efficacy and safety: the more malleable stylet 1 did not result in clinically significant oropharyngeal trauma, but was also a less effective deviation tool.
With regard to safety, we did not perform routine endoscopy in all patients. Accordingly, it is not possible to reliably comment on the correlation of LETElev, or lack thereof, and esophageal necrosis. In our prior published experience with MED (4), complete endoscopy of the esophagus, stomach, and duodenum was performed routinely on all patients post-procedure. The study demonstrated that although MED-related trauma did occur in 60% of subjects (as was expected), it did not result in any clinical sequelae. Based on these findings and our combined clinical experience with this technique, we no longer routinely perform post-MED endoscopy. Although endoscopy or imaging modalities such as computed tomography or magnetic resonance imaging may have provided additional information about subclinical mechanical esophageal injury, this was not performed in our study and is an important limitation from a safety perspective. Finally, it is notable that all of the procedures in our experience were performed in the setting of uninterrupted oral anticoagulation with either warfarin or, more frequently, a non-warfarin oral anticoagulant. This highlights the safety of this mechanical deviation strategy. Indeed, this is consistent with a recently published large consecutive series of 704 patients undergoing AF ablation in whom a transesophageal echocardiogram probe was used to mechanically deviate the esophagus (9). Although the correlation to esophageal heating was investigated in only a minority of this cohort (n = 25), this experience nonetheless speaks to the safety of mechanical displacement of the esophagus.
The effectiveness of MED differed depending on the lateral direction of excursion, favoring left-ward deviation (for right PV ablation): 1) an MEDEffective >20 mm was achieved almost 3 times more frequently for leftward deviation (32.1% vs. 11.9%), 2) the average extent of MEDEffective greater for leftward deviation (17.4 ± 8.3 mm vs. 12.2 ± 7.3 mm), and most important, 3) LETElev occurred almost twice as frequently during rightward deviation (48.6% vs. 25%). The reasons for this can be speculated to be related to thoracoabdominal anatomical variations between patients or could be technique specific. This suggests that, although the extent of deviation that can be achieved may be limited by certain patient factors, dedicated tools are needed; as such, the MED used in this study still needs further evaluation before being considered for routine clinical use. In the future, such tools may allow for greater and more consistent deviation, ease of use, and a favorable safety profile. Although LET elevations may indicate lack of sufficient lateral deviation, it is also possible that the MED itself displaces the esophagus closer to the posterior LA, making LET rises more frequent when deviation was suboptimal.
Although we did not have a comparative randomized cohort without MED, it was clear that there was an immediate improvement in workflow. That is, in previous cases when MED had not been used, it was invariably true that ablation lesions were truncated before adequate lesion could be made because of esophageal temperature elevations; this appeared to occur with much less frequency with MED. Of course, the most obvious safety advantage of esophageal deviation is the potential for avoiding atrioesophageal fistula formation. Although it seems self-evident that fistulas would be avoided if the esophagus is diverted from the point of thermal ablation, the relative rarity of fistula formation will make it virtually impossible to definitively prove that MED can prevent this often fatal complication. In addition to thermal injury, other mechanisms such as ischemic injury to the esophagus may also contribute to atrioesophageal fistula formation. On the other hand, it is interesting that in our series of >100 patients, we observed no instances of clinically evident gastric dysmotility, although this has been reported to occur only in about 1% to 2% of patients after AF ablation.
It is also notable that MED allowed us to use high power along the posterior wall (in the absence of esophageal heating); however, because of the thin nature of the posterior left atrial wall, ablation with high power should be performed with caution. Although certainly not provable from our series, this raises the possibility that the ablation time for achieving PV isolation could be reduced. It is also possible that MED might decrease the frequency of PV reconnection. This is particularly intriguing because we have recently demonstrated an association between esophageal heating and the subsequent development of PV reconnection (10). In a series of 142 patients undergoing redo ablation procedures (in whom we had performed esophageal temperature monitoring during the initial procedure), PV reconnections occurred in 20% of the PV pairs; interestingly, the point of reconnection for the majority (83%) of the lesion sets was along the posterior wall. Furthermore, there was a positive correlation between the occurrence of LETElev during the index ablation procedure and the point of PV reconnection along the inferior aspects of the posterior ablation lines. Further studies will be required to determine whether esophageal deviation will decrease the presence of PV reconnections along the posterior wall.
We demonstrate the ability of mechanical esophageal deviation during posterior LA ablation to achieve proportional reduction of LET rises with incremental degrees of esophageal deviation. Although esophageal deviation as performed in this study was able to achieve deviation, dedicated tools are required to consistently and safely achieve effective levels of esophageal deviation.
COMPETENCY IN MEDICAL KNOWLEDGE: Mechanical esophageal deviation is an attractive strategy to minimize esophageal heating during atrial fibrillation ablation. This has the potential to minimize thermal injury to the esophagus and improve procedural work flow by reducing the frequency of premature termination of ablation resulting from esophageal heating. In a study of 114 consecutive patients undergoing atrial fibrillation ablation, deviation performed using off-the-shelf mechanical stylet approach was demonstrated to be feasible and able to incrementally reduce esophageal heating depending on extent of lateral deviation.
TRANSLATIONAL OUTLOOK: Mechanical esophageal deviation to a distance exceeding 20 mm from the ablation line was optimal, whereas a distance <10 mm was largely ineffective. Achieving optimal deviation was difficult with this current technique. Better tools to achieve greater and more consistent esophageal deviation should be developed and evaluated.
Dr. Reddy has reported owning stock options in Circa Scientific, Inc, a manufacturer of esophageal temperature probes. All other authors have reported that they have relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- atrial fibrillation
- left atrium
- luminal esophageal temperature
- mechanical esophageal deviation
- pulmonary vein
- Received September 6, 2016.
- Revision received February 27, 2017.
- Accepted March 5, 2017.
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