Computed tomographic analysis of the anatomy of the left atrium and the esophagus: implications for left atrial catheter ablation

Impact of combining ablation index-guided and very high-power short-duration ablation at posterior wall adjacent to esophagus during perioperative period on procedural factors

INTRODUCTION

The impact of combining ablation index (AI)-guided and very high-power short-duration (vHPSD) ablation on procedural factors at the posterior wall near the esophagus is unclear.

METHODS

Atrial fibrillation patients who underwent initial ablation using three-dimensional mapping were enrolled. Patients were classified into two groups: those who underwent only AI-guided pulmonary vein isolation (PVI) (AI group) and those who underwent vHPSD ablation at the posterior wall adjacent to the esophagus in addition to AI-guided PVI (AI + vHPSD group). Differences in myocardial injury, inflammation, procedural characteristics, and pulmonary vein (PV) reconnection patterns were assessed between the two groups.

RESULTS

This study included 167 patients (AI group, 83 patients; AI+vHPSD group, 84 patients). No significant differences in high-sensitive troponin I or changes in inflammatory markers between pre- and Postablation were observed in either group. Total application time and total application energy were significantly lower in the AI+vHPSD group than in the AI group (p < 0.001 for both) despite no significant difference in the total number of applications between the groups. The incidence of esophagus temperature ≥40 degrees was significantly lower in the AI+vHPSD group than in the AI group (p = 0.036). However, the incidence of PV reconnections near the esophagus was significantly higher in the AI+vHPSD group than in the AI group (11.9% vs 3.6%, p = 0.046), despite no significant difference in the incidence of PV reconnections overall.

CONCLUSION

The combination of AI-guided PVI and vHPSD adjacent to the esophagus demonstrated reduced application energy requirements and maintained safety and effectiveness during the perioperative period.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

The influence of epicardial adipose tissue on the prognosis of atrial fibrillation patients undergoing radiofrequency ablation combined with left atrial appendage occlusion

Atrial fibrillation is the most common arrhythmia in adults. The interplay between epicardial adipose tissue and atrial fibrillation has garnered significant scientific interest. Recently, the combined approach of radiofrequency ablation and left atrial appendage occlusion has become a widely adopted strategy for managing non-valvular atrial fibrillation patients at high risk of thrombus formation. This study aims to assess the prognostic significance of epicardial adipose tissue volume in patients undergoing radiofrequency ablation in conjunction with left atrial appendage occlusion. This study results indicate that in patients undergoing the one-stop procedure, which comprises catheter radiofrequency ablation and percutaneous left atrial appendage occlusion, epicardial adipose tissue volume is significantly associated with AF recurrence post-strategy. Higher EATV predicts AF recurrence (HR = 1.17, 95%CI1.047-1.192, P = 0.001) and thromboembolism (P = 0.002) following the one-stop procedure. Epicardial adipose tissue volume serves as a significant predictor of atrial fibrillation recurrence following the one-stop procedure (area under the curve 0.648, 95%CI0.571-0.725, P = 0.002, sensitivity 0.88, specificity 0.50).

The Functional substrate in patients with atrial fibrillation is predictive of recurrences after catheter ablation

BACKGROUND

Enhanced characterization of the atrial electrical substrate may lead to better comprehension of atrial fibrillation (AF) pathophysiology.

OBJECTIVE

With the use of high-density substrate mapping, we sought to investigate the occurrence of functional electrophysiological phenomena in the left atrium and to assess potential association with arrhythmia recurrences after catheter ablation.

METHODS

Sixty-three consecutive patients with AF referred for ablation were enrolled. Analysis of conduction abnormalities relied on two acquired left atrial electroanatomic maps (sinus and atrial paced rhythm). We classified conduction abnormalities as fixed (if these were present in both rhythms) or functional rhythm dependent (if unmasked in one of the two rhythms). Esophagus and aorta locations were recorded to check the correspondence with abnormal conduction sites.

RESULTS

There were 234 conduction abnormalities detected, of which 125 (53.4%) were functional rhythm dependent. The most frequent anatomic site of functional phenomena was the anterior wall, followed by the posterior wall, in sinus rhythm and the pulmonary venous antra in paced rhythm. Sites of functional phenomena in 82.6% of cases corresponded with extracardiac structures, such as sinus of Valsalva of ascending aorta anteriorly and the esophagus posteriorly. Most (88%) areas with functional phenomena had normal bipolar voltage. After pulmonary vein ablation, the number of residual functional phenomena is an independent predictor of AF recurrence (hazard ratio, 2.539 [1.458-4.420]; P = .001) with a risk of recurrences at multivariable Cox analysis.

CONCLUSION

Dual high-density mapping (during sinus and paced rhythms) is able to unmask functional, rhythm-dependent phenomena that are predictive of AF recurrences during follow-up.

Esophageal Damage Following Left Atrial Ablation in a Patient on Dabigatran: Adding Insult to Injury

Dabigatran, a commonly prescribed anticoagulant medication, has been associated with esophagitis, referred to as dabigatran-induced esophagitis (DIE). We report a case of DIE occurring in a patient following left atrial ablation for atrial fibrillation. This case emphasizes the importance of recognizing the possible combined detrimental effects of left atrial ablation and dabigatran on the esophageal mucosa and highlights the clinical and endoscopic characteristics associated with DIE.

LEARNING POINTS

Dabigatran-induced esophagitis (DIE) should be considered in patients on dabigatran developing esophageal symptoms after radiofrequency ablation for atrial fibrillation.DIE is a condition characterized clinically by symptoms related to esophageal dysfunction and histologically by significant inflammation of the esophageal mucosa.Physicians should be aware of the signs and symptoms of DIE and must educate patients on proper medication administration to avoid such risks.

Utility of CT and MRI in Cardiac Electrophysiology

Cardiac electrophysiology involves the diagnosis and management of arrhythmias. CT and MRI play an increasingly important role in cardiac electrophysiology, primarily in preprocedural planning of ablation procedures but also in procedural guidance and postprocedural follow-up. The most common applications include ablation for atrial fibrillation (AF), ablation for ventricular tachycardia (VT), and for planning cardiac resynchronization therapy (CRT). For AF ablation, preprocedural evaluation includes anatomic evaluation and planning using CT or MRI as well as evaluation for left atrial fibrosis using MRI, a marker of poor outcomes following ablation. Procedural guidance during AF ablation is achieved by fusing anatomic data from CT or MRI with electroanatomic mapping to guide the procedure. Postprocedural imaging with CT following AF ablation is commonly used to evaluate for complications such as pulmonary vein stenosis and atrioesophageal fistula. For VT ablation, both MRI and CT are used to identify scar, representing the arrhythmogenic substrate targeted for ablation, and to plan the optimal approach for ablation. CT or MR images may be fused with electroanatomic maps for intraprocedural guidance during VT ablation and may also be used to assess for complications following ablation. Finally, functional information from MRI may be used to identify patients who may benefit from CRT, and cardiac vein mapping with CT or MRI may assist in planning access. ©RSNA, 2024 Supplemental material is available for this article.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

CAR and CSTR Cardiac Computed Tomography (CT) Practice Guidelines: Part 2-Non-Coronary Imaging

The cardiac computed tomography (CT) practice guidelines provide an updated review of the technological improvements since the publication of the first Canadian Association of Radiologists (CAR) cardiac CT practice guidelines in 2009. An overview of the current evidence supporting the use of cardiac CT in the most common clinical scenarios, standards of practice to optimize patient preparation and safety as well as image quality are described. Coronary CT angiography (CCTA) is the focus of Part I. In Part II, an overview of cardiac CT for non-coronary indications that include valvular and pericardial imaging, tumour and mass evaluation, pulmonary vein imaging, and imaging of congenital heart disease for diagnosis and treatment monitoring are discussed. The guidelines are intended to be relevant for community hospitals and large academic centres with established cardiac CT imaging programs.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Mechanisms of action behind the protective effects of proactive esophageal cooling during radiofrequency catheter ablation in the left atrium

Proactive esophageal cooling for the purpose of reducing the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation procedures is increasingly being used and has been Food and Drug Administration cleared as a protective strategy during left atrial RF ablation for the treatment of atrial fibrillation. In this review, we examine the evidence supporting the use of proactive esophageal cooling and the potential mechanisms of action that reduce the likelihood of atrioesophageal fistula (AEF) formation. Although the pathophysiology behind AEF formation after thermal injury from RF ablation is not well studied, a robust literature on fistula formation in other conditions (eg, Crohn disease, cancer, and trauma) exists and the relationship to AEF formation is investigated in this review. Likewise, we examine the abundant data in the surgical literature on burn and thermal injury progression as well as the acute and chronic mitigating effects of cooling. We discuss the relationship of these data and maladaptive healing mechanisms to the well-recognized postablation pathophysiological effects after RF ablation. Finally, we review additional important considerations such as patient selection, clinical workflow, and implementation strategies for proactive esophageal cooling.

Symptoms of gastroesophageal reflux disease predicts low voltage zones in the posteroinferior left atrium in patients with persistent atrial fibrillation

Background

The presence of low voltage zones (LVZs) in the left atrium (LA) is associated with the recurrence of atrial fibrillation (AF) after pulmonary vein isolation. Numerous studies have posited a link between gastroesophageal reflux disease (GERD) and AF, attributing this relationship to the anatomical proximity of the esophagus to the posteroinferior wall of the LA.

Objective

The objective of this study was to investigate whether GERD can predict the presence of LVZs in the posteroinferior wall of the LA.

Methods

Five hundred fifty-one patients with persistent AF, scheduled for their first AF ablation procedure, were prospectively enrolled. Voltage maps were collected using a multipolar catheter, and LVZs were defined as areas measuring ≥3 cm2 with a peak-to-peak bipolar voltage of <0.5 mV. Information on GERD symptoms was collected from the participants through a self-administered questionnaire.

Results

Long-standing persistent AF was present in 22.3% of the total cohort. GERD was present in 29% of patients and LVZs in the posteroinferior wall in 12.7%. In the multivariable analysis, patients with GERD were found to have more than twice the odds (odds ratio 2.26; 95% confidence interval 1.24-4.13; P = .008) of exhibiting LVZs in the posteroinferior wall of the LA than patients without GERD. GERD was not associated with LVZs in any other region of the LA.

Conclusion

GERD was found to be independently associated with LVZs in the posteroinferior LA. This association may be attributable to inflammation and may partly explain the link between GERD and AF.

Characteristics of radiofrequency lesions in patients with symptomatic periesophageal vagal nerve injury after pulmonary vein isolation

Background

Periesophageal vagal nerve injury (PNI) is an unpredictable and serious complication of atrial fibrillation (AF) ablation. We aimed to identify the factors associated with symptomatic PNI.

Methods

This study included 1391 patients who underwent ablation index-guided pulmonary vein isolation (PVI) using the CARTO system. The target ablation index was set at 550, except for the left atrial (LA) posterior wall near the esophagus, where radiofrequency (RF) power and duration were limited. Ten patients (0.72%) were diagnosed with symptomatic PNI. We randomly selected 40 patients without PNI (1:4 ratio) matched based on age, sex, body mass index, LA diameter, type of AF, and esophageal location. We measured the shortest distance from the RF lesions to the esophagus (LED) and classified the RF lesions according to the LED into four groups: 0-5, 5-10, 10-15, and 15-20 mm. We conducted a comparative analysis of classified RF lesions between patients with PNI (n = 10) and those without (n = 40).

Results

The contact force at LED 0-5 mm was significantly higher in patients with PNI than in those without (14.6 ± 1.7 vs. 12.0 ± 2.9 g; p = .01). Multivariate logistic analysis revealed that the independent factor for PNI was contact force at an LED of 0-5 mm (odds ratio: 1.506; 95% confidence interval: 1.053-2.153; p = .025).

Conclusions

The symptomatic PNI was significantly associated with a higher contact force near the esophagus. Strategies for regulating contact force near the esophagus may aid in the prevention of PNI.

Pre- and post-procedural cardiac imaging (computed tomography and magnetic resonance imaging) in electrophysiology: a clinical consensus statement of the European Heart Rhythm Association and European Association of Cardiovascular Imaging of the European Society of Cardiology

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging-specifically MR-may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

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.

Esophageal image segmentation for guidance of posterior wall lesions during atrial fibrillation ablation

BACKGROUND

Despite luminal esophageal temperature (LET) monitoring, esophageal injury remains a risk which impacts decision making during atrial fibrillation (AF) ablation. We sought to compare procedural characteristics including radiofrequency (RF) power, duration, and LET, among ablation procedures with and without image segmentation for esophageal visualization (EV).

METHODS

The retrospective cohort included 73 patients (mean age 65.2 ± 8.6 years, 36% female, 55% paroxysmal AF) who underwent pre-procedural cardiac magnetic resonance or computed tomography and LET monitoring. Of all patients, 35 were historical patients that underwent standard AF ablation without EV, and 38 were contemporary patients, 28 of whom underwent AF ablation with EV and 10 that underwent AF ablation without EV.

RESULTS

Total RF time was similar between the groups. The distribution of ablation power delivery was skewed toward higher power in the contemporary patients. However, among patients in the contemporary group, the proportion of > 35 Watts lesions was lower with EV (P < 0.001). There was no difference between the max or mean LET. The standard deviation of LET change within patient during posterior wall ablation was lower in those with esophageal visualization compared to historical controls, but no change was seen compared to a smaller group of contemporary controls. No long-term clinical esophageal injury was observed.

CONCLUSIONS

In a retrospective analysis, EV was successfully performed in 28 patients. EV impacted RF power delivery decisions but was unassociated with RF time, changes in LET, or long-term safety.

Atrial fibrillation ablation: the position of computed tomography in pre-procedural imaging

Atrial fibrillation (AF) is the most common supraventricular arrhythmia. Despite significant advances in its treatment, it still remains one of the leading causes of cardiovascular morbidity and mortality. In the last two decades, pulmonary vein isolation (PVI) was developed as the most effective treatment option. The reported effectiveness of a single ablation procedure ranges from 40% to 69% with single, and up to 88% with repeated procedures, with acceptable safety profile. The PubMed database was searched, using terms including ‘atrial fibrillation ablation’, ‘pulmonary vein isolation’, ‘computed tomography’, ‘pulmonary vein anatomy’ and ‘ovality index’. Papers were reviewed for relevance and scientific merit. Different imaging techniques are used for pre-procedural assessment of left atrial (LA) anatomy, of which computed tomography (CT) is the most common. It allows assessing pulmonary vein (PV) anatomy, the LA wall thickness in different regions and the left atrial appendage (LAA) anatomy, together with excluding the presence of intracardiac thrombi. Pre-procedural PVs imaging is important regardless of the selected ablation technique, however, cryoballoon (CB) ablation seems to be particularly anatomy-dependent. Additionally, CT also permits assessment of several PVs characteristics (geometry, dimensions, angulations, the ostium area, orientation and ovality index (OI), which are essential for the patients’ qualification and designing the strategy of AF ablation. In this paper, we have reviewed the role of CT imaging in patients undergoing ablation procedure due to recurrent/symptomatic atrial fibrillation. Moreover, we discussed the relevant literature.

Esophageal safety in CLOSE-guided 50W high-power-short-duration pulmonary vein isolation - The PREHEAT-PVI-Registry

AIMS

Pulmonary vein isolation (PVI) using high-power-short-duration (HPSD) radiofrequency ablation (RF) is emerging as the standard of care for treatment of atrial fibrillation (AF). While procedural short-term to mid-term efficacy and efficiency are very promising, this registry aims to investigate esopahgeal safety using an optimized ablation approach.

METHODS

In a single-centre experience, 388 consecutive standardized first-time AF ablation were performed using a CLOSE-guided-fixed-50W-circumferential PVI and substrate modification without intraprocedural oesophageal temperature measurement. 300 patients underwent post-procedural esophageal endoscopy to diagnose and grade endoscopically detected esophageal lesions (EDEL) and were included in the analysis.

RESULTS

EDEL were detected in 35 of 300 patients (11.6%), 25 of 35 were low-grade KCC 1 lesions with fast healing tendencies. 6 patients suffered KCC 2a lesions, 4 patients had KCC 2b lesions (1.3% of all patients). No esophageal perforation or fistula formation was observed. Patient baseline characteristics, especially patients age, gender and body-mass-index did not influence EDEL incidence. Additional posterior box isolation did not increase the incidence of EDEL. In patients diagnosed with EDEL, mean catheter contact force during posterior wall ablation was higher (11.9 ± 1.8 vs. 14.7 ± 3 grams, p<0.001), mean RF duration was shorter (11.9 ± 1 vs. 10.7 ± 1.2 sec., p<0.001), while achieved AI was not different between groups (434 ± 4.9 vs. 433 ± 9.5, n.s.).

CONCLUSIONS

Incidence of EDEL after CLOSE-guided-50W-HPSD PVI is lower compared to historical cohorts using standard-power RF settings. Catheter contact force during posterior HPSD ablation should not exceed 15 grams. This article is protected by copyright. All rights reserved.

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.

Esophageal thermal lesions in radiofrequency ablation for atrial fibrillation: A prospective comparative study of thermal sensors

BACKGROUND

Esophageal thermal lesion (ETL) is a complication of radiofrequency ablation for atrial fibrillation (RFAF). To prospectively compare the incidence of ETL, we used two linear, five- and three-sensor esophageal thermal monitoring catheters (ETMC5 and ETMC3). We also evaluated the predictors of ETL.

METHODS

Patients receiving their first RFAF (n = 106) were randomized into two groups, ETMC5 (n = 52) and ETMC3 (n = 54). Ablation was followed by esophagogastroduodenoscopy within 3 days.

RESULTS

Esophageal thermal lesion was detected in 7/106 (6.6%) patients (ETMC5: 3/52 [5.8%] vs. ETMC3: 4/54 [7.4%]; p = 1.0). The maximum temperature and number of measurements > 39.0°C did not differ between the groups (ETMC5: 40.5°C and 5.4 vs. ETMC3: 40.6°C and 4.9; p = .83 and p = .58, respectively). In ETMC5 group, the catheter had to be moved significantly less often (0.12 vs. 0.42; p = .0014) and fluoroscopy time was significantly shorter (79.2 min vs. 101.7 min; p = .0038) compared with ECMC3 group. The total number of ablations in ETMC5 group was significantly greater (50.2 vs. 37.7; p = .030) and ablation time was significantly longer (52.1 min vs. 40.1 min; p = .0039). Only body mass index (BMI) was significantly different between patients with and without ETL (21.4 ± 2.5 vs. 24.3 ± 3.4; p = .022).

CONCLUSIONS

The incidence of ETL was comparable between ETMC5 and ETMC3 groups; however, fluoroscopy time, total ablation time, and total number of ablations differed significantly. Lower BMI may increase the risk of developing ETL.

Short-Term Natural Course of Esophageal Thermal Injury After Ablation for Atrial Fibrillation

PURPOSE

To provide insight into the short-term natural history of esophageal thermal injury (ETI) after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) by esophagogastroduodenoscopy (EGD).

METHODS

We screened patients who underwent RFCA for AF and EGD based on esophageal late gadolinium enhancement (LGE) in post ablation MRI. Patients with ETI diagnosed with EGD were included. We defined severity of ETI according to Kansas City classification (KCC): type 1: erythema; type 2: ulcers (2a: superficial; 2b deep); type 3 perforation (3a: perforation; 3b: perforation with atrioesophageal fistula). Repeated EGD was performed within 1-14 days after the last EGD if recommended and possible until any certain healing signs (visible reduction in size without deepening of ETI or complete resolution) were observed.

RESULTS

ETI was observed in 62 of 378 patients who underwent EGD after RFCA. Out of these 62 patients with ETI, 21% (13) were type 1, 50% (31) were type 2a and 29% (18) were type 2b at the initial EGD. All esophageal lesions, but one type 2b lesion that developed into an atrioesophageal fistula (AEF), showed signs of healing in repeated EGD studies within 14 days after the procedure. The one type 2b lesion developing into an AEF showed an increase in size and ulcer deepening in repeat EGD 8 days after the procedure.

CONCLUSION

We found that all ETI which didn't progress to AEF presented healing signs within 14 days after the procedure and that worsening ETI might be an early signal for developing esophageal perforation. This article is protected by copyright. All rights reserved.

The Esophagus Going Steady

Ablation is a cornerstone of treatment for atrial fibrillation (AF), with increasing data on its safety and efficacy. This article is protected by copyright. All rights reserved.

Preoperative Personalization of Atrial Fibrillation Ablation Strategy to Prevent Esophageal Injury: Impact of Changes in Esophageal Position

INTRODUCTION

Due to changes in esophageal position, preoperative assessment of the esophageal location may not mitigate the risk of esophageal injury in catheter ablation for atrial fibrillation (AF). This study aimed to assess esophageal motion and its impact on AF ablation strategies.

METHODS AND RESULTS

Ninety-seven AF patients underwent 2 computed tomography (CT) scans. The area at risk of esophageal injury (AAR) was defined as the left atrial surface ≤3 mm from the esophagus. On CT1, ablation lines were drawn blinded to the esophageal location to create 3 ablation sets: individual pulmonary vein isolation (PVI), wide antral circumferential ablation (WACA), and WACA with linear ablation (WACA+L). Thereafter, ablation lines for WACA and WACA+L were personalized to avoid the AAR. Rigid registration was performed to align CT1 onto CT2, and the relationship between ablation lines and the AAR on CT2 was analyzed. The esophagus moved by 3.6 [2.7 to 5.5] mm. The AAR on CT2 was 8.6 ± 3.3 cm² , with 77% overlapping that on CT1. High body mass index was associated with the AAR mismatch (standardized β 0.382, P <0.001). Without personalization, AARs on ablation lines for individual PVI, WACA, and WACA+L were 0 [0-0.4], 0.8 [0.5-1.2], 1.7 [1.2-2.0] cm² . Despite the esophageal position change, the personalization of ablation lines for WACA and WACA+L reduced the AAR on lines to 0 [0-0.5] and 0.7 [0.3-1.0] cm² (P <0.001 for both).

CONCLUSION

The personalization of ablation lines based on a preoperative CT reduced ablation to the AAR despite changes in esophageal position. This article is protected by copyright. All rights reserved.

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.

Intraluminal Esophageal Temperature Monitoring Using the Circa S-Cath™ Temperature Probe to Guide Left Atrial Ablation in Patients with Atrial Fibrillation

Introduction

Radiofrequency catheter ablation is a common treatment for atrial fibrillation (AF), during which thermal esophageal injury may rarely occur and lead to an atrio-esophageal fistula. Therefore, we studied the utility of the Circa S-Cath™ multi-sensor luminal esophageal temperature (LET) probe to prevent esophageal thermal injury.

Methods and Results

Thirty-six patients, enrolled prospectively, underwent circumferential or segmental pulmonary vein isolation for treatment of AF. A maximum ablation electrode temperature of 42ºC was programmed for automatic power delivery cutoff. In addition, energy delivery was manually discontinued when the maximum LET on any sensor of the probe rose abruptly (i.e. ˃0.2ºC) or exceeded 39º C. Esophagoscopy was performed immediately after ablation in 18 patients (with the temperature probe still in place) and at approximately 24 hours after ablation in 18 patients. Esophageal lesions were classified as likely traumatic or thermally related. Of the 36 patients enrolled in the study, 21 had persistent and 15 had paroxysmal AF, average LVEF 57±16% and CHA2DS2VASc score 1.6±1.2 (range 0-4). Average maximum LET was 37.8±1.4ºC, power delivery 31.1±8 watts and ablation electrode temperature 36.4±4.1ºC. Average maximum contact force was 44.5±20.5 grams where measured. Only 1 patient (<3%) had an esophageal lesion that could potentially represent thermal injury and 4 patients (11.1%) had minor traumatic mechanical injury.

Conclusions

LET guided titration of power and duration of energy application, using an insulated multi-sensor esophageal temperature probe, is associated with a low risk of esophageal thermal injury during AF ablation. In only rare cases, LET monitoring resulted in the need to manipulate the esophagus to avoid unacceptable temperature rises, that could not be achieved by adjustment of power and duration of energy application.

Real-time visualization of the esophagus and left atrial posterior wall by intra-left atrial echocardiography

PURPOSE

Localization of the esophagus and the left atrium (LA) posterior wall thickness (LAPWT) should be taken into account when delivering radiofrequency energy. To validate the visualization of the esophagus and analyze LAPWT by ICE advanced into the LA in patients with atrial fibrillation (AF) undergoing ablation index (AI)-guided pulmonary vein (PV) isolation.

METHODS

In 73 patients (mean age, 68 ± 12; paroxysmal AF in 45), a 3-dimensional (3D) esophagus image was created with CARTO Soundstar^Ⓡ and its location was compared with contrast esophagography saved in Carto UNIVU™. LAPWT adjacent to the esophagus was measured at 4 levels: left superior PV (LSPV), intervenous carina (IC), left inferior PV (LIPV), and LIPV bottom. A target AI value was 260 (25 W power) on the esophagus demonstrated by ICE.

RESULTS

All patients had the esophagus posterior to the left PV antrum. Creating a 3D esophagus and measurement of LAPWT with ICE was done without any complications. ICE esophagus image was completely overlapped with contrast esophagography. LAPWT (mm) was 2.8 (interquartile range, 2.5-3.2), 2.2 (1.9-2.5), 1.9 (1.8-2.1), and 2.1 (1.9-2.4) for LSPV, IC, LIPV, and LIPV bottom, respectively, while LA roof thickness was 3.2 (2.9-3.6) (P < 0.0001 by ANOVA). No residual conduction gap on the esophagus after the first circumferential PV isolation was found in 64 of 73 (88%) patients.

CONCLUSIONS

ICE inserted into the LA can reliably locate and display the esophagus and its relationship to the LA. LAPWT was the thinnest at the LIPV level. AI-guided ablation targeting at AI value 260 on the esophagus seemed to be effective.

Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies

INTRODUCTION

Thermally induced cardiac lesions result in necrosis, edema, and inflammation. This tissue change may be seen with ultrasound. In this study, we sought to use intracardiac echocardiography (ICE) to evaluate pulmonary vein tissue morphology and assess the acute tissue changes that occur following radiofrequency (RF) or laser ablation for atrial fibrillation (AF).

METHODS AND RESULTS

Patients with AF underwent pulmonary vein isolation (PVI) using irrigated RF or laser balloon. Pre- and post-ablation ICE imaging was performed from within each pulmonary vein (PV). At least 10 transverse imaging planes per PV were evaluated and each plane was divided into eight segments. The PV/atrial wall thickness and the luminal area were measured at each segment. Twenty-seven patients underwent PVI (15 with laser, 12 with RF). Ninety-eight pulmonary veins were analyzed (58 PVs laser; 40 PVs RF). At baseline, there were no regional differences in PV wall thickness in the right-sided veins. The anterior regions of left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) were significantly thicker compared with the posterior and inferior regions (p < .01). Post-ablation, PV wall thickness in RF group increased 24.1% interquartile range (IQR) (17.2%-36.7%) compared with 1.2% IQR (0.4%-8.9%) in laser group, p = .004. In all PVs, RF ablation resulted in significantly greater percent increase in wall thickness compared with laser. Additionally, RF resulted in more variable changes in regional PV wall thickness; with more increases in wall thickness in anterior versus posterior LSPV (75.4 ± 58.5% vs. 46.8 ± 55.6%, p < .01), anterior versus posterior right superior pulmonary vein (RSPV) (62.9 ± 63.9% vs. 44.6 ± 51.7%, p < .05), and superior versus inferior RSPV (69.1 ± 45.4% vs. 35.9 ± 45%, p < .05). There were no significant regional differences in PV wall thickness changes for the laser group.

CONCLUSIONS

Rotational ICE can be used to measure acute tissue changes with ablation. Regional variability in baseline wall thickness was nonuniformly present in PVs. Acute tissue changes occurred immediately post-ablation. Compared with laser balloon, RF shows markedly more thickening post-ablation with significant regional variations.

Rare presentation of atrial myxoma: chest pain, dysphagia and left upper extremity weakness

Atrial myxoma is a benign primary heart tumour, which can be found incidentally on imaging studies. It is usually located in the left atrium and may manifest as dyspnoea, chest pain, heart failure, cough, shortness of breath when rising from a recumbent position, haemoptysis, hoarseness and as a source of cardiac embolism. However, dysphagia caused by an atrial myxoma has been reported only twice in the literature. We present a 53-year-old Caucasian man with a chronic history of dysphagia caused by an atrial myxoma, in which surgical resection resulted in complete resolution of his dysphagia.

Posterior Left Atrial Adipose Tissue Attenuation Assessed by Computed Tomography and Recurrence of Atrial Fibrillation After Catheter Ablation

[Figure: see text].

Standardised computed tomographic assessment of left atrial morphology and tissue thickness in humans

AIMS

Left atrial (LA) remodelling is a common feature of many cardiovascular pathologies and is a sensitive marker of adverse cardiovascular outcomes. The aim of this study was to establish normal ranges for LA parameters derived from coronary computed tomographic angiography (CCTA) imaging using a standardised image processing pipeline to establish normal ranges in a previously described cohort.

METHODS

CCTA imaging from 193 subjects recruited to the Budapest GLOBAL twin study was analysed. Indexed LA cavity volume (LACVi), LA surface area (LASAi), wall thickness and LA tissue volume (LATVi) were calculated. Wall thickness maps were combined into an atlas. Indexed LA parameters were compared with clinical variables to identify early markers of pathological remodelling.

RESULTS

LACVi is similar between sexes (31 ml/m2 v 30 ml/m2) and increased in hypertension (33 ml/m2 v 29 ml/m2, p = 0.009). LASAi is greater in females than males (47.8 ml/m2 v 45.8 ml/m2 male, p = 0.031). Median LAWT was 1.45 mm. LAWT was lowest at the inferior portion of the posterior LA wall (1.14 mm) and greatest in the septum (median = 2.0 mm) (p < 0.001). Conditions known to predispose to the development of AF were not associated with differences in tissue thickness.

CONCLUSIONS

The reported LACVi, LASAi, LATVi and tissue thickness derived from CCTA may serve as reference values for this age group and clinical characteristics for future studies. Increased LASAi in females in the absence of differences in LACVi or LATVi may indicate differential LA shape changes between the sexes. AF predisposing conditions, other than sex, were not associated with detectable changes in LAWT.Clinical trial registration:http://www.ClinicalTrials.gov/NCT01738828.

Anatomical insights into posterior wall isolation in patients with atrial fibrillation: A hypothesis to protect the esophagus

INTRODUCTION

Left atrial posterior wall (LAPW) isolation may be performed as an additional atrial fibrillation (AF) ablation strategy based on pulmonary vein isolation. A modified posterior-inferior line (MPL) was proposed for reducing esophageal injury. The aim of this study was to evaluate the anatomical characteristics of the MPL, compared with the conventional posterior line (CPL).

METHODS AND RESULTS

Multidetector computed tomography was performed in 102 consecutive AF patients (male/female = 60/42) preoperative, and the parameters were evaluated as follows: the distance from MPL and CPL to the esophagus, fat pad presence and thickness in the course of MPL and CPL, and the esophageal route below CPL. The average distance from the MPL to the esophagus was longer than from CPL to the esophagus (3.7 ± 1.5 vs. 1.7 ± 0.4 mm, p < .001). Proportion of fat pad was higher in the course of MPL than CPL. The myocardium tissue and fat pad under MPL was thicker than under CPL (2.9 ± 1.1 vs. 1.6 ± 0.3 mm, p < .001; 1.4 ± 0.6 vs. 0.9 ± 0.2 mm, p < .001), respectively. In patients whose esophagus was unconfined in a triangular space at the left inferior pulmonary vein level, the average distance from MPL to esophagus was longer than the confined patients (4.0 ± 1.7 vs. 3.2 ± 1.0 mm, p = .001).

CONCLUSION

The MPL was far away from the esophagus with thicker myocardium tissue and more fat pad than the CPL; thus, MPL could serve as a favorable alternative in linear ablation for LAPW isolation.

Anatomy of the Pericardial Space

The pericardial cavity and its boundaries are formed by the reflections of the visceral and parietal pericardial layers. This space is an integral access point for epicardial interventions. As the pericardial layers reflect over the great vessels and the heart, they form sinuses and recesses, which restrict catheter movement. The epicardial vasculature is also important when performing nearby catheter ablation. The phrenic nerve and esophagus are other important structures to appreciate so as to avoid collateral injury. In addition, the Larrey space, or left sternocostal triangle, is a key avascular window through which pericardial access can be safely achieved.

An Insight to the Role of Thermal Effects on the Onset of Atrioesophageal Fistula: A Computer Model of Open-Irrigated Radiofrequency Ablation

PURPOSE

Atrial fibrillation (AF) is the most common heart rhythm disorder in the world. Radiofrequency catheter ablation (RFCA) has become the preferred method of treatment for drug-refractory AF. One of the rare (< 0.2%) but deadly (≈ 80%) complications of RFCA is Atrioesophageal fistula (AEF). Although the exact pathophysiological events in developing AEF are not fully understood, one hypothesis is that the underlying cause may be thermal damage to the mucosa (the esophagus lumen).

METHOD

The present study reports on a computer model of RFCA in the posterior wall of the left atrium (LA) which is in close proximity to the esophagus. A novel systematic approach was taken by considering a range of anatomical variations (obtained from clinical data) to study the spatial and temporal temperature data when RF energy was applied to cause a threshold temperature of 50 °C in the mucosa. The model is also used to investigate the spatial and temporal changes in mucosal temperature that may affect the reliability of the readings from esophageal temperature monitoring devices if they are not positioned accurately.

RESULTS

The results suggest evidence of transmural esophageal lesions in all the anatomies except one, if the 50 °C temperature threshold is the only criteria used for identification of thermal damage. However, by taking into consideration the effect of time (temperature-time integral), only some anatomies were identified as being partially damaged. Investigating the temperature and the temperature gradient data during the ablation revealed that the increases in both the temperature and the temperature gradient were time, location and anatomy dependent. This finding may have significance in the design and development of next-generation temperature monitoring devices that will provide a temperature map rather than single point measurements.

CONCLUSION

Studies such as the present work may provide more convenient platforms for investigating the effect of the many factors involved in the RF procedure and how they may link to the development of AEF.

Prevention of Esophageal Damage During Ablation of Atrial Fibrillation by the Esophagus Mechanical Deviation

Atrial fibrillation is the most prevalent arrhythmia in the world population. Despite the use of antiarrhythmics, it is difficult to control clinically, causing symptoms and mainly generating risk of a thromboembolic event. Since 1998, by means of radiofrequency ablation, the treatment of atrial fibrillation has completely changed, but together with this important evolution complications from this ablative treatment technique have also started. In addition to the pulmonary vein stenosis caused by the ablation and later corrected with the change in the technique, atrioesophageal fistulas appeared due to the application of radiofrequency in the posterior wall of the left atrium. This wall is very close (0.5 cm onaverage) to the esophagus, which facilitates the formation of the fistula that leads to the death of almost 100% of the affected patients, despite the various treatment measurements already developed. To avoid this serious complication, several authors have created techniques to protect the esophagus including its mechanical deviation to a region opposite to the radiofrequency application, taking advantage of its mobility and easiness of handling. The mechanical deviation of the esophagus has proven to be the simplest, cheapest and most efficient way to protect this organ from radiofrequency thermal damage during atrial fibrillation ablation.

Prevenção de Dano Esofágico Durante Ablação de Fibrilação Atrial por Desvio Mecânico do Esôfago

A fibrilação atrial é a arritmia de maior prevalência na população mundial. Apesar do uso de antiarrítmicos, é de difícil controle clínico, ocasionando sintomas e principalmente gerando risco de um evento tromboembólico. A partir de 1998, por meio da ablação por radiofrequência, o tratamento da fibrilação atrial mudou completamente, porém junto a essa importante evolução também iniciaram as complicações advindas dessa técnica de tratamento ablativo. Além das estenoses das veias pulmonares causadas pela ablação e posteriormente corrigidas com a mudança da técnica, surgiram as fístulas átrio-esofágicas, devido à aplicação de radiofrequência na parede posterior do átrio esquerdo. Esta parede está bem próxima (0,5 cm em média) do esôfago, facilitando a formação da fístula que leva à morte quase 100% dos pacientes acometidos, apesar das diversas medidas de tratamento já desenvolvidas. Para evitar essa grave complicação, vários autores criaram técnicas para proteger o esôfago incluindo seu desvio mecânico para uma região oposta à da aplicação de radiofrequência, aproveitando a sua mobilidade e facilidadede abordagem. O desvio mecânico do esôfago tem se mostrado a forma mais simples, barata e eficiente de proteger esse órgão da lesão térmica da radiofrequência durante a ablação da fibrilação atrial.

Simple calculation of the optimal insertion depth of esophageal temperature probes in children

Placing an esophageal temperature probe (ETP) in the optimal esophageal site is important in various anesthetic and critical care settings to accurately monitor the core temperature of a pediatric patient. However, no reported study has provided a formula to calculate the optimal insertion depth of ETP placement in children based on direct measurement of the optimal depth. The aim of this study was to develop a simple and reliable method to determine the optimal depth of ETP placement in children via their mouth. Using preoperative chest computed tomography scans, intraoperative chest X-rays, and the actual depth of ETP insertion, we measured the optimal depth of ETP placement retrospectively in 181 children aged 3-13 years who underwent minimally invasive repairs of the pectus excavatum and removal of a pectus bar. A linear regression analysis was performed to assess the correlation of the optimal depth of ETP placement with the children's age, weight, and height. The optimal depth of ETP placement had a greater correlation with height than with age or weight, and the best-fit equation was '0.180 × height + 6.749 (cm) (R² = 0.920).' We obtained three simplified formulae, which showed no statistically significant difference in predicting the optimal depth of ETP placement: height/6 + 8 (cm), height/5 + 4 (cm), and height/5 + 5 (cm). The optimal depth of ETP via children's mouths has a close correlation with height and can be calculated with a simple formula 'height/5 + 5 (cm)'.

Different tissue thermodynamics between the 40 W and 20 W radiofrequency power settings under the same ablation index/lesion size index

INTRODUCTION

The ablation index (AI) and lesion size index (LSI) are novel markers for predicting the ablation lesion quality, however, collateral damage is still a concern. This study aimed to compare the lesion characteristics and tissue temperature profiles between 20 W (20 Ws) and 40 W (40 Ws) ablation settings under the same AI and LSI.

METHODS

An ex vivo model consisting of swine myocardium (5-6 mm thickness) in a circulating, warmed saline bath was used. Twenty-one tissue temperature electrodes were used. Radiofrequency applications with different power settings were performed with a 10 to 12 g contact force until the AI and LSI reached 350 and 4.5, respectively.

RESULTS

A total of 120 radiofrequency (RF) applications and 2520 tissue temperature profiles were analyzed. The speed of the tissue temperature rise with 40 Ws was significantly faster than that with 20 Ws. However, the maximum tissue temperature did not significantly differ between 20 and 40 Ws with the same AI (44.6°C ± 3.9°C vs 45.1°C ± 6.4°C, P = .73), and was significantly lower for 40 Ws with the same LSI (42.8°C ± 3.4°C vs 40.0°C ± 3.4°C, P = .003). For both the AI and LSI, the number of electrodes exhibiting high temperatures (≥39°C) was significantly larger and the duration of high tissue temperatures was significantly longer with 20 Ws. The thermal latency with 40 Ws was greater.

CONCLUSIONS

Although the targeted AI and LSI were the same for both 20 and 40 Ws, the tissue temperature profiles differed greatly depending on the RF power setting. A high power setting based on the AI and LSI may reduce the collateral thermal damage.

RESCUE-AF in Patients Undergoing Atrial Fibrillation Ablation: The RESCUE-AF Trial

BACKGROUND

Although contact force (CF)–sensing catheters improve procedural effectiveness and safety of atrial fibrillation ablation, recent reports documented a higher incidence of atrioesophageal fistula formation relative to ablation with non–CF-sensing catheters.The present study was to assess whether restricting CF to <20 g reduced risk for esophageal injury (EI) in patients with atrial fibrillation undergoing circumferential pulmonary vein isolation.

METHODS

This prospective, single-center, randomized study enrolled 89 consecutive patients (mean age, 57.2±11.3 years; 57.3% men) with atrial fibrillation (68.5% paroxysmal and 31.5% persistent). Computed tomography angiography, transesophageal echocardiography, and esophageal endoscopy were conducted before the procedure, and a repeat esophageal endoscopy was performed after the procedure. Patients were randomized to restricted-CF group (n=44) or non-CF group (n=45), with circumferential pulmonary vein isolation using a CF-sensing (CF restricted to <20 g) or non–CF-sensing catheter, respectively. The primary end point was rate of EI post ablation.

RESULTS

Baseline characteristics were evenly distributed between groups, without a case of preprocedural EI. With the same power setting, similar ablation time and average measured catheter tip temperature during posterior wall ablation just opposite to the esophagus in all patients in the restricted-CF group versus non-CF groups, there were no cases versus 9 (20%) cases of EI post ablation, respectively, with similar rate of freedom from atrial tachyarrhythmias at mean 31.3±6.5 months follow-up (68.2% versus 64.4%; P=0.3798).

CONCLUSIONS

Risk for EI was minimized when CF was restricted to <20 g at the posterior left atrial wall, where the circumferential pulmonary vein isolation lesion set and the course of the esophagus overlapped in all subjects.

Analysis for the primary predictive factor for the incidence of esophageal injury after ablation of atrial fibrillation

BACKGROUND

Esophageal injury (EI) is a serious complication that occurs after catheter ablation of atrial fibrillation (AF), however predictable factor of EI is unclear.

METHODS

Among 308 patients who underwent AF ablation, upper gastrointestinal tract endoscopy was performed the next day after ablation to examine for EI. To define the primary factor that predicts EI, patients' characteristics, number and amount of radiofrequency energy applied to the posterior wall, ablation procedure, and the shortest distance between esophagus and posterior left atrium measured on contrast computed tomography (SD-CT) were analyzed.

RESULTS

EI was found in 27 patients (8.8%). There were no significant differences in the patient characteristics, number and amount of radiofrequency energy applied to posterior wall or ablation procedure between patients with (Injury Group) and without EI (Non-Injury Group). However, SD-CT in the Injury Group was significantly shorter than that in Non-Injury Group (2.3±0.6mm vs 4.1±0.9mm, p<0.001). The area under a receiver operating characteristic curve using SD-CT as a predictive marker in EI patients was 0.988 (p<0.001). When the cut-off value of SD-CT was set at 2.9mm, the sensitivity and specificity for EI diagnosis were 92.3% and 96.8%, and the positive predictive value and negative predictive value were 0.75 and 0.99, respectively.

CONCLUSIONS

EI observed after catheter ablation of AF was closely associated with the SD-CT. Patients with SD-CT below 2.9mm have a potential risk of EI and thus must be strictly followed.

Fully automatic segmentation and objective assessment of atrial scars for long-standing persistent atrial fibrillation patients using late gadolinium-enhanced MRI

PURPOSE

Atrial fibrillation (AF) is the most common heart rhythm disorder and causes considerable morbidity and mortality, resulting in a large public health burden that is increasing as the population ages. It is associated with atrial fibrosis, the amount and distribution of which can be used to stratify patients and to guide subsequent electrophysiology ablation treatment. Atrial fibrosis may be assessed noninvasively using late gadolinium-enhanced (LGE) magnetic resonance imaging (MRI) where scar tissue is visualized as a region of signal enhancement. However, manual segmentation of the heart chambers and of the atrial scar tissue is time consuming and subject to interoperator variability, particularly as image quality in AF is often poor. In this study, we propose a novel fully automatic pipeline to achieve accurate and objective segmentation of the heart (from MRI Roadmap data) and of scar tissue within the heart (from LGE MRI data) acquired in patients with AF.

METHODS

Our fully automatic pipeline uniquely combines: (a) a multiatlas-based whole heart segmentation (MA-WHS) to determine the cardiac anatomy from an MRI Roadmap acquisition which is then mapped to LGE MRI, and (b) a super-pixel and supervised learning based approach to delineate the distribution and extent of atrial scarring in LGE MRI. We compared the accuracy of the automatic analysis to manual ground truth segmentations in 37 patients with persistent long-standing AF.

RESULTS

Both our MA-WHS and atrial scarring segmentations showed accurate delineations of cardiac anatomy (mean Dice = 89%) and atrial scarring (mean Dice = 79%), respectively, compared to the established ground truth from manual segmentation. In addition, compared to the ground truth, we obtained 88% segmentation accuracy, with 90% sensitivity and 79% specificity. Receiver operating characteristic analysis achieved an average area under the curve of 0.91.

CONCLUSION

Compared with previously studied methods with manual interventions, our innovative pipeline demonstrated comparable results, but was computed fully automatically. The proposed segmentation methods allow LGE MRI to be used as an objective assessment tool for localization, visualization, and quantitation of atrial scarring and to guide ablation treatment.

Left Atrial Epicardial Fat Volume Is Associated With Atrial Fibrillation: A Prospective Cardiovascular Magnetic Resonance 3D Dixon Study

BACKGROUND

Recent studies demonstrated a strong association between atrial fibrillation (AF) and epicardial fat around the left atrium (LA). We sought to assess whether epicardial fat volume around the LA is associated with AF, and to determine the additive value of LA-epicardial fat measurements to LA structural remodeling for identifying patients with AF using 3-dimensional multi-echo Dixon fat-water separated cardiovascular magnetic resonance.

METHODS AND RESULTS

A total of 105 subjects were studied: 53 patients with a history of AF and 52 age-matched patients with other cardiovascular diseases but no history of AF. The 3-dimensional multi-echo Dixon fat-water separated sequence was performed for LA-epicardial fat measurements. AF patients had significantly greater LA-epicardial fat (28.9±12.3 and 14.2±7.3 mL for AF and non-AF, respectively; P<0.001) and LA volume (110.8±38.2 and 89.7±30.3 mL for AF and non-AF, respectively; P=0.002). LA-epicardial fat adjusted for LA volume was still higher in patients with AF compared with those without AF (P<0.001). LA-epicardial fat and hypertension were independently associated with the risk of AF (odds ratio, 1.17; 95% confidence interval, 1.10%-1.25%, P<0.001, and odds ratio, 3.29; 95% confidence interval, 1.17%-9.27%, P=0.03, respectively). In multivariable logistic regression analysis adjusted for body surface area, LA-epicardial fat remained significant and an increase per mL was associated with a 42% increase in the odds of AF presence (odds ratio, 1.42; 95% confidence interval, 1.23%-1.62%, P<0.001). Combined assessment of LA-epicardial fat and LA volume provided greater discriminatory performance for detecting AF than LA volume alone (c-statistic=0.88 and 0.74, respectively, DeLong test; P<0.001).

CONCLUSIONS

Cardiovascular magnetic resonance 3-dimensional Dixon-based LA-epicardial fat volume is significantly increased in AF patients. LA-epicardial fat measured by 3-dimensional Dixon provides greater performance for detecting AF beyond LA structural remodeling.

Upper gastrointestinal complications following ablation therapy for atrial fibrillation

BACKGROUND

Following ablation therapy for cardiac arrhythmias, patients may develop upper gastrointestinal (UGI) symptoms. The vagus nerve is close to the atria and may be affected by ablating energy.

AIM

To identify structural or functional complications in UGI tract following ablation for atrial fibrillation (AF) and clinical outcomes and association with vagal dysfunction.

METHODS

Using natural language processing of electronic medical records and an AF ablation database of 5380 patients treated during 17 years, we identified 40 patients with UGI complications. We evaluated vagal dysfunction by electrocardiogram (ECG) showing lack of sinus arrhythmia (variation in R-R interval by ≥120 milliseconds, in presence of normal sinus P waves and constant P-R interval).

KEY RESULTS

Among 40 patients: (A) eight had structural GI complications confirmed by diagnostic tests: seven with esophageal ulcer/erosions and no signs of UGI bleeding and one developed esophagopericardial fistula (and survived with treatment); (B) 15 had functional UGI complications confirmed by objective motility tests. Nine had newly developed symptoms and six had aggravated symptoms; and (C) the remaining 17 had GI symptoms without relevant diagnostic results. Most UGI issues resolved spontaneously or with conservative treatment. However, 2 died several weeks after ablation procedure; cause of death was suspected atrioesophageal fistula or esophageal rupture. Vagal dysfunction persisted for 3 months in 13 and was transient in 8.

CONCLUSIONS/INFERENCES

Although most GI issues resolved spontaneously, there should be a high index of clinical suspicion in patients with persistent symptoms. Vagal dysfunction may serve as a marker of more extensive tissue damage.