Feasibility, safety, and efficacy of a novel preshaped nitinol esophageal deviator to successfully deflect the esophagus and ablate left atrium without esophageal temperature rise during atrial fibrillation ablation: The DEFLECT GUT study

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

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

BACKGROUND

Esophageal perforation and fistula formation are rare but serious complications following atrial fibrillation ablation. In this review article, we outline the incidence, pathophysiology, predictors, and preventative strategies of this dreaded complication.

METHODS

We conducted an electronic search in 10 databases/electronic search engines to access relevant publications. All articles reporting complications following atrial fibrillation ablation, including esophageal injury and fistula formation, were included for systematic review.

RESULTS

A total of 130 manuscripts were identified for the final review process. The overall incidence of esophageal injury following atrial fibrillation ablation was significantly higher with thermal ablation modalities (radiofrequency 5-40%, cryoballoon 3-25%, high-intensity focused ultrasound < 10%) as opposed to non-thermal ablation modalities (no cases reported to date). The incidence of esophageal perforation and fistula formation with the use of thermal ablation modalities is estimated to occur in less than 0.25% of all atrial fibrillation ablation procedures. The use of luminal esophageal temperature monitoring probe and mechanical esophageal deviation showed protective effect toward reducing the incidence of this complication. The prognosis is very poor for patients who develop atrioesophageal fistula, and the condition is rapidly fatal without surgical intervention.

CONCLUSIONS

Esophageal perforation and fistula formation following atrial fibrillation ablation are rare complications with poor prognosis. Various strategies have been proposed to protect the esophagus and reduce the incidence of this fearful complication. Pulsed field ablation is a promising new ablation technology that may be the future answer toward reducing the incidence of esophageal complications.

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

BACKGROUND

Injury to the esophagus has been reported in a high percentage of patients undergoing ablation of atrial fibrillation (AF).

OBJECTIVES

This study assessed the incidence of esophageal injury in patients undergoing ablation of AF with and without an esophageal deviating device.

METHODS

This prospective, randomized, multicenter, double-blinded, controlled Food and Drug Administration investigational device exemption trial compared the incidence of ablation-related esophageal lesions, as assessed by endoscopy, in patients undergoing AF ablation assigned to a control group (luminal esophageal temperature [LET] monitoring alone) compared with patients randomized to a deviation group (esophagus deviation device + LET). This novel deviating device uses vacuum suction and mechanical deflection to deviate a segment of the esophagus, including the trailing edge.

RESULTS

The data safety and monitoring board recommended stopping the study early after randomizing 120 patients due to deviating device efficacy. The primary study endpoint, ablation injury to the esophageal mucosa, was significantly less in the deviation group (5.7%) in comparison to the control group (35.4%; P < 0.0001). Control patients had a significantly higher severity and greater number of ablation lesions per patient. There was no adverse event assigned to the device. By multivariable analysis, the only feature associated with reduced esophageal lesions was randomization to deviating device (OR: 0.13; 95% CI: 0.04-0.46; P = 0.001). Among control subjects, there was no difference in esophageal lesions with high power/short duration (31.8%) vs other radiofrequency techniques (37.2%; P = 0.79).

CONCLUSIONS

The use of an esophageal deviating device resulted in a significant reduction in ablation-related esophageal lesions without any adverse events.

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

BACKGROUND

Esophageal luminal temperature monitoring is a commonly used strategy to reduce esophageal thermal injury in catheter ablation for atrial fibrillation (AFib).

OBJECTIVES

We sought to compare the incidence of endoscopically detected esophageal lesions (EDEL) between two commonly used esophageal luminal temperature probes.

METHODS

Consecutive patients undergoing ablation with esophageal luminal temperature monitoring and upper endoscopy within 24 h after ablation were included.

RESULTS

Four hundred forty-five patients (64 ± 10 years, 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).

CONCLUSIONS

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.

Safety of an esophageal deviator for atrial fibrillation catheter ablation

Background

Esophageal thermal injury is a complication of atrial fibrillation (AF) ablation, and it can be avoided by esophageal deviation during left atrial posterior wall radiofrequency catheter ablation.

Objective

This study aimed to evaluate the safety of a nitinol-based mechanical esophageal displacement device (MEDD) and its performance.

Methods

This preclinical safety study was conducted on 20 pigs, with 10 undergoing radiofrequency AF ablation using the MEDD and 10 serving as a control group under anticoagulation but without radiofrequency application. Esophageal traumatic injuries were classified from 0 to 4 and were grouped as absent (grade 0), minor (grade 1 or 2), moderate (grade 3), or major risk lesions (grade 4) by anatomopathological study. Grades 1 and 2 were considered acceptable. Fluoroscopy was used to measure displacement.

Results

Five (25%) pigs developed traumatic lesions, 4 with grade 1 and 1 with grade 2 (2-mm superficial ulcer). There was no difference in lesion occurrence between the radiofrequency and control groups (30% and 20%, respectively; P = .43). Under rightward displacement, the right edge moved 23.9 (interquartile range [IQR] 21.3-26.3) mm and the left edge moved 16.3 (IQR 13.8-18.4) mm (P < .001) from baseline. Under leftward displacement, the right edge moved 13.5 (IQR 10.9-15.3) mm and the left edge moved 16.5 (IQR 12.3-18.5) mm (P = .07). A perforation to the pharyngeal diverticulum occurred in 1 pig, related to an accidental extubation.

Conclusion

In pigs, the MEDD demonstrated safety in relation to esophageal tissue, and successful deviation. Esophageal traumatic injuries were acceptable, but improper manipulation led to pharyngeal lesion.

A novel esophageal retractor with eccentric balloon during atrial fibrillation ablation

BACKGROUND

Due to the anatomically adjacent relationship between the left atrium (LA) and esophagus, energy delivery on the posterior wall of LA is limited. The aim of this study was to evaluate the feasibility of a novel esophageal retractor (SAFER) with an inflatable C-curve balloon during atrial fibrillation (AF) ablation.

METHOD

Nine patients underwent AF ablation assisted with the SAFER. After inflation, the esophagus was deviated laterally away from the intended ablation site of the posterior wall under local anesthesia. The extent of mechanical esophageal deviation (MED) was evaluated under fluoroscopy, defined as the shortest distance from the trailing esophageal edge to the closest point of the ablation line. Gastroscopy was performed before and after ablation. The target ablation index used in all LA sites including the posterior wall was 400-450 after effective MED. All adverse events during the periprocedural period were recorded.

RESULTS

The mean deviation distance achieved 16.2 ± 9.6 mm away from the closest ablation point of the pulmonary vein lesion set. With respect to the individual left and right pulmonary vein lesion sets, the deviation distance was 19.7 ± 11.5 and 12.7 ± 6.8 mm, respectively. The extent of deviation was 0 to 5 mm, 5.1 to 10 mm, or >10 mm in 0(0%), 7(38.9%), and 11(61.1%), respectively. Procedural success was achieved in all patients without acute reconnection. There was only one esophageal complication which manifested as esophageal erosion and this patient experienced throat pain possibly related to the SAFER retractor with no clinical sequelae.

CONCLUSION

Esophageal deviation with the novel eccentric balloon is a novel feasible choice during AF ablation, enabling adequate energy delivery to the posterior wall of LA. Additional prospective randomized controlled studies are required for further validation.

Epicardial connections and bi-atrial tachycardias: From anatomy to clinical practice

Bi-atrial tachycardia (BiAT) is not rare after extensive atrial ablation or cardiac surgery. The complexity of bi-atrial reentrant circuits poses a great challenge for clinical practice. With recent advances in mapping technologies, we are now able to characterize atrial activation in detail. However, given the involvement of both atria and multiple epicardial conductions, endocardial mapping for BiATs is not easy to understand. Knowledge of the atrial myocardial architecture is the foundation for the clinical management of BiATs; as it is required to understand the possible mechanism of the tachycardia and identify the optimal target of ablation. In this review we summarize current knowledge about the anatomy of interatrial connections as well as other epicardial fibers and discuss the interpretation of electrophysiological findings and ablation strategies for BiATs.

Epicardial Roof-Dependent Macro-Re-Entrant Tachycardia After Ablation of Atrial Fibrillation: Electrophysiological Characteristics and Ablation

BACKGROUND

Epicardial roof-dependent macro-re-entrant tachycardias (epi-RMAT) after catheter ablation of persistent atrial fibrillation are not rare but the prevalence and characteristics remain unclear.

OBJECTIVES

The purpose of this study was to investigate the prevalence, electrophysiological characteristics and ablation strategy of recurrent epi-RMATs after ablation of atrial fibrillation.

METHODS

A total of 44 consecutive patients with 45 roof-dependent RMATs after atrial fibrillation ablation were enrolled. High-density mapping and appropriate entrainment were performed to diagnose epi-RMATs.

RESULTS

Epi-RMAT was identified in 15 patients (34.1%). Under the right lateral view, the activation pattern can be briefly classified into clockwise re-entry (n = 4), counterclockwise re-entry (n = 9), and bi-atrial re-entry (n = 2). Five (33.3%) had a pseudofocal activation pattern. All epi-RMATs had continuous slow or no conduction zone with a mean width of 21.3 ± 12.3 mm traversing both pulmonary antra, and 9 (60.0%) had missing cycle length of >10% actual cycle length. Compared with endocardial RMAT (endo-RMAT), epi-RMAT required longer ablation time (9.60 ± 4.98 minutes vs 3.68 ± 3.42 minutes; P < 0.001), more floor line ablation (93.3% vs 6.7%; P < 0.001), and electrogram-guided posterior wall ablation (78.6% vs 3.3%; P < 0.001). Electric cardioversion was required in 3 patients (20.0%) with epi-RMATs, whereas all endo-RMATs were terminated by radiofrequency applications (P = 0.032). Posterior wall ablation was performed under esophagus deviation in 2 patients. We did not observe a significant difference in the recurrence of atrial arrhythmias between patients with epi-RMATs and endo-RMATs after the procedure.

CONCLUSIONS

Epi-RMATs are not uncommon after roof or posterior wall ablation. An explicable activation pattern with a conduction obstacle in the dome and appropriate entrainment is critical for the diagnosis. The effectiveness of posterior wall ablation may be restricted by the risk of esophagus impairment.

Fluoroless catheter ablation of atrial fibrillation: a step-by-step workflow

Catheter ablation is an important therapeutic strategy for patients with atrial fibrillation (AF). While some critical steps of the procedure have traditionally relied on fluoroscopy, advances in electroanatomic mapping and the growing use of intracardiac echocardiography have made non-fluoroscopic AF ablation a reality. This hands-on review provides an overview on how to perform radiofrequency ablation of AF without the use of fluoroscopy, focusing on technical aspects, new technologies, and troubleshooting.

Relationship between the posterior atrial wall and the esophagus: esophageal position and temperature measurement during atrial fibrillation ablation (AWESOME-AF). A randomized controlled trial

BACKGROUND

Pulmonary vein isolation (PVI) implies unavoidable ablation lesions to the left atrial posterior wall, which is closely related to the esophagus, leading to several potential complications. This study evaluates the usefulness of the esophageal fingerprint in avoiding temperature rises during paroxysmal atrial fibrillation (PAF) ablation.

METHODS

Isodistance maps of the atrio-esophageal relationship (esophageal fingerprint) were derived from the preprocedural computerized tomography. Patients were randomized (1:1) into two groups: (1) PRINT group, the PVI line was modified according to the esophageal fingerprint; (2) CONTROL group, standard PVI with operator blinded to the fingerprint. The primary endpoint was temperature rise detected by intraluminal esophageal temperature probe monitoring. Ablation settings were as specified on the Ablate BY-LAW study protocol.

RESULTS

Sixty consecutive patients referred for paroxysmal AF ablation were randomized (42 (70%) men, mean age 60 ± 11 years). Temperature rise (> 39.1 °C) occurred in 5 (16%) patients in the PRINT group vs. 17 (56%) in the CONTROL group (p < 0.01). Three AF recurrences were documented at a mean follow-up of 12 ± 3 months (one (3%) in the PRINT group and 2 (6.6%) in the CONTROL group, p = 0.4).

CONCLUSION

The esophageal fingerprint allows for a reliable identification of the esophageal position and its use for PVI line deployment results in less frequent esophageal temperature rises when compared to the standard approach. Further studies are needed to evaluate the impact of PVI line modification to avoid esophageal heating on long-term outcomes. The development of new imaging-derived tools could ultimately improve patient safety (NCT04394923).

Radiofrequency Pulmonary Vein Isolation without Esophageal Temperature Monitoring: Contact-Force Characteristics and Incidence of Esophageal Thermal Damage

Esophageal thermal lesions following pulmonary vein isolation (PVI) for atrial fibrillation (AF) potentially harbor lethal complications. Radiofrequency (RF)-PVI using contact force-technology can reduce collateral damage. We evaluated the incidence of endoscopically detected esophageal lesions (EDEL) and the contribution of contact force to esophageal lesion formation without esophageal temperature monitoring. One hundred and thirty-one AF patients underwent contact force-guided RF-PVI. Contact force, energy, force-time-integral, and force-power-time-integral were adopted. During PVI at the posterior segment of the wide antral circumferential line, limits were set for energy (30 W), duration (30 s) and contact force (40 g). Ablations were analyzed postero-superior and -inferior around PVs. Endoscopy within 120 h identified EDEL in six patients (4.6%). In EDEL(+), obesity was less frequent (17% vs. 68%, p = 0.018), creatinine was higher (1.55 ± 1.18 vs. 1.07 ± 0.42 mg/dL, p = 0.016), and exclusively at the left postero-inferior site, force-time-integral and force-power-time-integral were greater (2973 ± 3267 vs. 1757 ± 1262 g·s, p = 0.042 and 83,547 ± 105,940 vs. 43,556 ± 35,255 g·J, p = 0.022, respectively) as compared to EDEL(-) patients. No major complications occurred. At 12 months, arrhythmia-free survival was 74%. The incidence of EDEL was low after contact force-guided RF-PVI. Implementing combined contact force-indices on the postero-inferior site of left-sided PVs may reduce EDEL.

Protecting Against Collateral Damage to Non-cardiac Structures During Endocardial Ablation for Persistent Atrial Fibrillation

Injury to structures adjacent to the heart, particularly oesophageal injury, accounts for a large proportion of fatal and life-altering complications of ablation for persistent AF. Avoiding these complications dictates many aspects of the way ablation is performed. Because avoidance involves limiting energy delivery in areas of interest, fear of extracardiac injury can impede the ability of the operator to perform an effective procedure. New techniques are becoming available that may permit the operator to circumvent this dilemma and deliver effective ablation with less risk to adjacent structures. The authors review all methods available to avoid injury to extracardiac structures to put these developments in context.

Innovations in atrial fibrillation ablation

BACKGROUND

Catheter-based ablation to perform pulmonary vein isolation (PVI) has established itself as a mainstay in the rhythm control strategy of atrial fibrillation. This review article aims to provide an overview of recent advances in atrial fibrillation ablation technology.

METHODS

We reviewed the available literature and clinical trials of innovations in atrial fibrillation ablation technologies including ablation catheter designs, alternative energy sources, esophageal protection methods, electroanatomical mapping, and novel ablation targets.

RESULTS

Innovative radiofrequency (RF) catheter designs maximize energy delivery while avoiding overheating associated with conventional catheters. Single-shot balloon catheters in the form of cryoballoons, radiofrequency, and laser balloons have proven effective at producing pulmonary vein isolation and improving procedural efficiency and reproducibility. Pulsed field ablation (PFA) is a highly anticipated novel nonthermal energy source under development, which demonstrates selective ablation of the myocardium, producing durable lesions while also minimizing collateral damage. Innovative devices for esophageal protection including esophageal deviation and cooling devices have been developed to reduce esophageal complications. Improved electroanatomical mapping systems are being developed to help identify additional non-pulmonary triggers, which may benefit from ablation, especially with persistent atrial fibrillation. Lastly, the vein of Marshall alcohol ablation has been recently studied as an adjunct therapy for improving outcomes with catheter ablation for persistent atrial fibrillation.

CONCLUSIONS

Numerous advances have been made in the field of atrial fibrillation ablation in the past decade. While further long-term data is still needed for these novel technologies, they show potential to improve procedural efficacy and safety.

Preventing esophageal complications from atrial fibrillation ablation: A review

Atrioesophageal fistula is a life-threatening complication of ablation treatment for atrial fibrillation. Methods to reduce the risk of esophageal injury have evolved over the last decade, and diagnosis of this complication remains difficult and therefore challenging to treat in a timely manner. Delayed diagnosis leads to treatment occurring in the context of a critically ill patient, contributing to the poor prognosis associated with this complication. The associated mortality risk can be as high as 70%. Recent important advances in preventative techniques are explored in this review.

Preventative techniques used in current clinical practice are discussed, which include high-power short-duration ablation, esophageal temperature probe monitoring, cryotherapy and laser balloon technologies, and use of proton pump inhibitors. A lack of randomized clinical evidence for the effectiveness of these practical methods are found. Alternative methods of esophageal protection has emerged in recent years, including mechanical deviation of the esophagus and esophageal temperature control (esophageal cooling). Although these are fairly recent methods, we discuss the available evidence to date. Mechanical deviation of the esophagus is due to undergo its first randomized study. Recent randomized study on esophageal cooling has shown promise of its effectiveness in preventing thermal injuries. Lastly, novel ablation technology that may be the future of esophageal protection, pulsed field ablation, is discussed.

The findings of this review suggest that more robust clinical evidence for esophageal protection methods is warranted to improve the safety of atrial fibrillation ablation.

Recovery of Conduction Following High-Power Short-Duration Ablation in Patients With Atrial Fibrillation: A Single-Center Experience

[Figure: see text].

Clinical Manifestations, Outcomes, and Mortality Risk Factors of Atrial-Esophageal Fistula: A Systematic Review

INTRODUCTION

Atrial-esophageal fistula (AEF) is a rare but life-threatening complication of catheter ablation. The clinical presentation and mortality risk factors of AEF have not been fully elucidated. The aim of this study was to systematically review the clinical characteristics and prognosis of AEF.

METHODS

PubMed was searched from inception to October 2020 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement protocol.

RESULTS

A total of 190 AEF patients were included. The mean age was 59.29 ± 11.67 years, 74.21% occurred in males, and 81.58% underwent radiofrequency ablation. AEF occurred within 30 days after ablation in 80.82% of patients and occurred later in patients presenting with neurological symptoms compared with other symptoms (median of onset time: 27.5 days vs. 16 days, p < 0.001). Clinical presentation included fever (81.58%) and neurological symptoms (80.53%). Chest computed tomography (abnormal rate of 91.24%) was the preferred diagnostic test, followed by magnetic resonance imaging of the brain (abnormal rate of 90.91%). Repeated testing improved diagnostic evaluation sensitivity. Distinctive imaging results included free air in the mediastinum (incidence rate of 81.73%) and air embolism of the brain (incidence rate of 57.53%). The overall mortality was 63.16%, with worse nonsurgical treatment outcomes compared with outcomes of surgical treatment (94.19% vs. 33.71%, p < 0.001). Conservative or stent intervention was an independent risk factor for mortality. Age (adjusted odds ratio, 1.063, p = 0.004), presentation with neurological symptoms (adjusted odds ratio, 5.706, p = 0.017), and presentation with gastrointestinal bleeds (adjusted odds ratio, 3.009, p = 0.045) were also predictors of mortality.

CONCLUSIONS

AEF is a fatal ablation complication. AEF can be diagnosed using a combination of a clinical history of ablation, infection, or neurological symptoms and an abnormal chest CT. Our analysis supports that surgical treatment reduces the mortality rate.

High-power, short-duration ablation for atrial fibrillation: Pros and cons

This article reviews and compares the rationale and evidence supporting high-power, short-duration radiofrequency (RF) ablation with those of conventional-power, conventional-duration RF ablation for atrial fibrillation (AF). The pros and cons of each approach, biophysics of ablation, pre-clinical studies informing clinical utilization, and the accumulated clinical evidence are presented. Both conventional-power, conventional-duration RF ablation and high-power, short-duration ablation are similarly safe, and effective approaches for AF ablation. Theoretical advantages of high-power, short-duration ablation, including greater procedure efficiency and limited conductive heating of collateral structures, must be weighed against the narrower safety margin related to rapid energy delivery during high power ablation.

The impact of mechanical oesophageal deviation on posterior wall pulmonary vein reconnection

AIMS

During atrial fibrillation ablation, oesophageal heating typically prompts reduction or termination of radiofrequency energy delivery. We previously demonstrated oesophageal temperature rises are associated with posterior left atrial pulmonary vein reconnection (PVR) during redo procedures. In this study, we assessed whether mechanical oesophageal deviation (MED) during an index procedure minimizes posterior wall PVRs during redo procedures.

METHODS AND RESULTS

Patients in whom we performed a first-ever procedure followed by a clinically driven redo procedure were divided based on both the use of MED for oesophageal protection and the ablation catheter employed (force or non-force sensing) in the first procedure. The PVR sites were compared between MED using a force-sensing catheter (MEDForce), or no MED with a non-force (ControlNoForce) or force (ControlForce) sensing catheter. Despite similar clinical characteristics, the MEDForce redo procedure rate (9.2%, 26/282 patients) was significantly less than the ControlNoForce (17.2%, 126/734 patients; P = 0.002) and ControlForce (17.5%, 20/114 patients; P = 0.024) groups. During the redo procedure, the posterior PVR rate with MEDForce (2%, 1/50 PV pairs) was significantly less than with either ControlNoForce (17.7%, 44/249 PV pairs; P = 0.004) or ControlForce (22.5%, 9/40 PV pairs; P = 0.003), or aggregate Controls (18.3%, 53/289 PV pairs; P = 0.006). However, the anterior PVR rate with MEDForce (8%, 4/50 PV pairs) was not significantly different than Controls (aggregate Controls-3.5%, 10/289 PV pairs, P = 0.136; ControlNoForce-2.4%, 6/249 PV pairs, P = 0.067; ControlForce-10%, 4/40 PV pairs, P = 1.0).

CONCLUSION

Oesophageal deviation improves the durability of the posterior wall ablation lesion set during AF ablation.

Reduced esophageal heating in high-power short-duration atrial fibrillation ablation in the contact force catheter era

BACKGROUND

 Atrial fibrillation (AF) ablation is alternative treatment to medical therapy. Most feared complication is atrioesophageal fistula METHODS: Observational, retrospective analysis of consecutive 355 patients undergoing first AF ablation. Low-power long-duration (LPLD) group contained 158 patients, with 121 (76.58%) having paroxysmal AF who underwent ablation with power 20/30W (anterior and posterior left atrial wall), 17 mL/min flow, and a contact force of 10-30 g for 30 s. High-power short-duration group (HPSD) contained 197 patients, with 113 (57.36%) having paroxysmal AF who underwent ablation at 45/50W of power with a contact force of 8-15 g/10-20 g and a 35 mL/min flow rate for 6-8 s on the anterior and the posterior left atrial wall, respectively. Both groups had pulmonary veins isolated and atrial flutter was ablated when needed. For patients not in sinus rhythm, cardioversion was performed before ablation RESULTS: There were no complications. LPLD group: Left atrial time 118.74 min, total 145.32 min, radiofrequency time 4317.99s, X-ray 13.42 min, and elevation of luminal esophageal temperature (LET) in 132 (84.53%) patients. HPSD group: Left atrial time 72.16 min, total 93.76 min, radiofrequency time 1511.29s, X-ray 7.6 min, and LET elevation in only 75 (38.07%) patients. A markedly higher rate of first-pass isolation was observed in HPSD compared to LPLD, 77.16% versus 13.29%, respectively. Recurrence occurred in 64 (40.50%) and 32 (16.24%) in 28.45 and 22.35 months in LPLD and HPSD patients, respectively. In LPLD, 10 patients were submitted to endoscopy, and one (10%) had mild erythema and in HPSD, 13 performed the endoscopy, with two (15.38%) patients showing mild erythema CONCLUSION: HPSD technique compared to the LPLD technique showed significant reduced radiofrequency and fluoroscopy times, higher rate of first-pass isolation, lower recurrence rate, and esophageal temperature elevation and may also have a protective effect avoiding incidental esophageal injury due to these findings.

Predictors of recurrent atrial fibrillation following catheter ablation

INTRODUCTION

Atrial fibrillation (AF) is a complex and multi-factorial rhythm disorder. Catheter ablation is widely used for the management of AF. However, it is limited by relapse of the arrhythmia necessitating repeat procedures.

AREAS COVERED

This review aims to discuss the predictors of post-ablation recurrent AF including age, gender, genetic predisposition, AF type and duration, comorbidities, lifestyle factors, echocardiographic parameters of heart chambers, left atrial fibrosis and ablation strategies and targets. An extensive literature search was undertaken on PubMed and Google Scholar to obtain full texts of relevant AF-related articles.

EXPERT OPINION

Maintenance of stable sinus rhythm is the main intended outcome of AF ablation. Therefore, it is very crucial to identify the risk factors that may influence the ablation success. Most of these predictors such as comorbidities, ablation strategy and targets and lifestyle factors are either reversible or modifiable. Thus, not only the awareness of these known risk factors by both patients and their physicians but also future research to identify the unknown predictors are critical to optimize care in this multi-faceted morbidity.

Protection of the esophagus during catheter ablation of atrial fibrillation

Esophageal injury still occurs with high frequency during ablation of atrial fibrillation (AF). The purpose of this study is to provide a review of methods to protect the esophagus from injury during AF ablation. Despite advances in imaging and ablation, the potential risk of esophageal injury during AF ablation remains an important concern with a high occurrence of esophageal injury (≈15%). There have been numerous studies evaluating varied techniques for esophageal protection including active cooling and displacement of the esophagus. These techniques are reviewed in this manuscript as well as the role of esophageal protection in managing patients undergoing AF ablation procedure.

Perioperative Imaging to Guide Epicardial Mapping and Ablation

Accessing the epicardial space without a sternotomy or a surgical pericardial window to treat ventricular arrhythmias in Chagas disease became a medical necessity in South America. Since the introduction of the dry percutaneous epicardial access approach, epicardial access has been standard procedure for management of ventricular arrhythmias in ischemic and nonischemic cardiomyopathies and atrioventricular accessory pathways after failed conventional endocardial ablation. Understanding the epicardial space and neighboring structures has become an important subject of teachings in electrophysiology. The evolution of complex ablation procedures to treat atrial and ventricular arrhythmias and device interventions to prevent cardioembolic stroke requires thorough understanding of pericardial anatomy.

Prevention and Treatment of Atrioesophageal Fistula Related to Catheter Ablation for Atrial Fibrillation

Atrioesophageal fistula (AEF) is an uncommon but devastating complication of catheter ablation for atrial fibrillation. Even with appropriate recognition and treatment, mortality is greater than 30% in most studies. If AEF is suspected, it is essential to avoid endoscopy and to order immediate cross-sectional imaging. If the diagnosis is confirmed, a thoracic surgeon should be promptly notified and must assess the patient urgently. The prognosis for AEF is poor even if it is appropriately recognized and addressed, so prevention must be a high priority. Prevention of AEF should involve the use of low-risk and cost-effective measures during ablation, which may increase safety, efficacy, or both. These strategies may include conscious sedation (as opposed to general anesthesia), low-power ablation, low-flow irrigation, short-duration lesions, esophageal temperature measurement, esophageal deviation, and pharmacologic prophylaxis with proton pump inhibitors or histamine H₂ receptor blockers. Multiple new technologies are now becoming available, which may further reduce esophageal injury. Proceduralists should be aware of the available techniques and equipment that may help to reduce the risk of AEF, while simultaneously considering the possibility of unintended consequences.

Current Status of Esophageal Protection

Catheter ablation of atrial fibrillation necessitates ablation on the posterior left atrium. The anterior esophagus touches the posterior left atrium, although its course is highly variable. The proximity of the left atrium to the esophagus confers risk of injury with radiofrequency and cryoablation owing to the heat transfer that occurs with thermal ablation. Early detection of esophageal temperature changes with probes may decrease the extent of damage to the esophagus, but evidence is mixed. Avoiding ablation on the esophagus with esophageal deviation and modifying ablation approaches may decrease the risk of injury.

Evaluation of a novel esophageal retractor utilizing vacuum suction and mechanical force for deviating the esophagus

BACKGROUND

Deviation of the esophagus prevents esophageal injury during atrial fibrillation ablation.

OBJECTIVES

This study is to evaluate, in animals, safety and effectiveness of a novel esophageal retractor that utilizes vacuum suction and mechanical force to deviate the esophagus.

METHODS

Following general anesthesia, a radiopaque ruler was placed behind the animal perpendicular to the esophagus. The esophageal retractor was inserted and esophagram was completed. Suction force (280-300 mm Hg) was applied to the distal aspect of the device that resulted in adherence of the esophagus in a circumferential manner. Then movement of a deflecting arm was used to deviate the esophagus. Four animal studies completed: (a) deviation distance and presence of trailing edge; (b) effect of 1 hour continuous suction and deviation upon esophageal cellular architecture; (c) impact on luminal esophageal temperature (LET) during high power ablation; and (d) compatibility of esophageal retractor with electroanatomic mapping system.

RESULTS

The distance of deviation to the right (26.6 ± 2.5 mm) was higher than to the left (18.7 ± 2.3 mm; P < .01). There was no esophageal trailing edge in 65/68 deviations (96%). With continuous suction for 1 hour, pathology revealed small, <1mm, circular area of hyperemia in the esophageal mucosa. During high power ablation, the maximum increase in LET was 0.2°C. Finally, there was no interference between the device and electro-anatomical mapping system.

CONCLUSION

In animal models, the esophageal retractor utilizing vacuum suction was successful at deviating the esophagus without significant trailing edge and with minor (1 mm) injury with prolonged continuous suction.

Prevention of left atrium esophagus fistula: Appraisal of existing technologies and strategies

Catheter ablation has emerged as an effective treatment for atrial fibrillation (AF). Atrial esophageal fistula (AEF) is a rare, but feared complication. With increasing utilization of ablation therapy for AF, the understanding of the relationship between AEF and ablation has been improved in recent years. Efforts to reduce the risk of AEF have focused on decreasing the risk of severe esophageal injury (EI) and the presumed subsequent progression from EI to AEF, including esophageal temperature monitoring, esophageal cooling systems, esophageal deviation devices, and decreasing and/or curtailing ablation energy delivery. Periprocedural assessment may help identify higher risk patients and detect early esophageal lesions. This review systematically summarizes and evaluates the current strategies and techniques utilized to reduce the risk of AEF in the clinical workflow for AF ablation. We expect that this review will help clinicians to better understand the principles, advantages, and disadvantages of these methods, and to find suitable strategies using current available tools.

Esophageal injury associated with catheter ablation for atrial fibrillation: Determinants of risk and protective strategies

Catheter ablation has become an important element in the management of atrial fibrillation. Several technical advances allowed for better safety profiles and lower recurrence rates, leading to an increasing number of ablations worldwide. Despite that, major complications are still reported, and esophageal thermal injury remains a significant concern as atrioesophageal fistula (AEF) is often fatal. Recognition of the mechanisms involved in the process of esophageal lesion formation and the identification of the main determinants of risk have set the grounds for the development and improvement of different esophageal protective strategies. More sensitive esophageal temperature monitoring, safer ablation parameters and catheters, and different energy sources appear to collectively reduce the risk of esophageal thermal injury. Adjunctive measures such as the prophylactic use of proton-pump inhibitors, as well as esophageal cooling or deviation devices, have emerged as complementary methods with variable but promising results. Nevertheless, as a multifactorial problem, no single esophageal protective measure has proven to be sufficiently effective to eliminate the risk, and further investigation is still warranted. Early screening in the patients at risk and prompt intervention in the cases of AEF are important risk modifiers and yield better outcomes.

The Year in Electrophysiology: Selected Highlights From 2018

This article is the first in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, the associate editor-in-chief, Dr. Augoustides, and the editorial board for the opportunity to start this series, namely the research highlights of the year that pertain to electrophysiology in relation to cardiothoracic and vascular anesthesia. This first article focuses on esophageal thermal injury during radiofrequency ablation, perioperative management of patients presenting for ablation procedures, left atrial appendage occlusion devices, and, finally, heart failure diagnostic devices.

Catheter Ablation of Paroxysmal Atrial Fibrillation Originating from Non-pulmonary Vein Areas

Pulmonary veins (PVs) are a major source of ectopic beats that initiate AF. PV isolation from the left atrium is an effective therapy for the majority of paroxysmal AF. However, investigators have reported that ectopy originating from non-PV areas can also initiate AF. Patients with recurrent AF after persistent PV isolation highlight the need to identify non-PV ectopy. Furthermore, adding non-PV ablation after multiple AF ablation procedures leads to lower AF recurrence and a higher AF cure rate. These findings suggest that non-PV ectopy is important in both the initiation and recurrence of AF. This article summarises current knowledge about the electrophysiological characteristics of non-PV AF, suitable mapping and ablation strategies, and the safety and efficacy of catheter ablation of AF initiated by ectopic foci originating from non-PV areas.

Persistent Atrial Fibrillation Ablation: Where Do We Go From Here?

Catheter ablation is being used increasingly for the treatment of atrial fibrillation (AF). Pulmonary vein antral isolation is considered the "cornerstone" for the ablation of AF. This approach has demonstrated consistent rates of success for paroxysmal AF, but the rates of success for persistent AF are lower. There has long been a hypothesis that additional ablation beyond pulmonary vein isolation is required to achieve better outcomes in the population with persistent AF. However, large clinical trials have demonstrated recently that such approaches as empiric linear ablation and/or ablation of complex fractionated electrograms may add no benefit over pulmonary vein isolation alone in persistent AF. Furthermore, new technologies are improving the durability and outcome of pulmonary vein isolation alone. These observations have endorsed a search for new potential targets for adjuvant ablation, which currently include ablation of dynamic phenomena during AF such as rotational and focal activations, ablation of scar regions in the atria, isolation of the left atrial posterior wall, and ablation of nonpulmonary vein triggers. Whether any of these additional approaches will add to the success of ablation for persistent AF is unknown. Smaller study results are mixed. Only the performance of large-scale randomized trials will definitively answer whether additional ablation over pulmonary vein isolation alone with improve outcomes for persistent AF.

The Impact of Advances in Atrial Fibrillation Ablation Devices on the Incidence and Prevention of Complications

The number of patients with atrial fibrillation currently referred for catheter ablation is increasing. However, the number of trained operators and the capacity of many electrophysiology labs are limited. Accordingly, a steeper learning curve and technical advances for efficient and safe ablation are desirable. During the last decades several catheter-based ablation devices have been developed and adapted to improve not only lesion durability, but also safety profiles, to shorten procedure time and to reduce radiation exposure. The goal of this review is to summarise the reported incidence of complications, considering device-related specific aspects for point-by-point, multi-electrode and balloon-based devices for pulmonary vein isolation. Recent technical and procedural developments aimed at reducing procedural risks and complications rates will be reviewed. In addition, the impact of technical advances on procedural outcome, procedural length and radiation exposure will be discussed.