Gaps after linear ablation of persistent atrial fibrillation (Marshall-PLAN): Clinical implication

Steps to improve the outcome of a single ablation procedure for paroxysmal atrial fibrillation: Significance of a burst stimulation-guided ablation strategy

BACKGROUND

The outcome of a single ablation procedure for paroxysmal atrial fibrillation (PAF) is suboptimal. The value of burst stimulation and additional ablation following the isolation of pulmonary vein (PV) and superior vena cava (SVC) remains unclear.

OBJECTIVE

The aim of this study was to optimize the ablation strategy and improve the outcome of a single procedure for PAF.

METHODS

This retrospective study involved 404 PAF patients who underwent radiofrequency ablation, and were divided into Group 1 (PV + SVC isolation, n = 81) and Group 2 (PV + SVC isolation + burst stimulation-guided ablation, n = 323). In Group 2, additional linear ablation was performed if atrial fibrillation (AF) or atrial flutter (AFL) persisted or was induced by burst stimulation after PV and SVC isolation.

RESULTS

In Group 1, 20 (24.69 %) patients experienced recurrences of AF (n = 16) and AFL (n = 4) during an average follow-up period of 733.60 days. In Group 2, 76 (23.53 %) patients experienced persistent arrhythmias (n = 25) or arrhythmias induced by burst stimulation (n = 51) after PV and SVC isolation, including AF (n = 27) and AFL (n = 49). Ablation along the left atrial roofline, mitral isthmus, and tricuspid isthmus was performed in 37, 34, and 49 patients, respectively. During the average follow-up duration of 660.80 days, the recurrence rate (29/323, 8.98 %) of AF/AFL was significantly lower in Group 2 than that in Group 1 (p < 0.001).

CONCLUSION

Additional stepwise linear ablation guided by burst stimulation significantly improved the outcome of a single ablation procedure for PAF.

Impact of High-Density Mapping on Pulmonary Vein Isolation Durability: A Randomized, Single-Center Study

BACKGROUND

Despite technical progress and novel ablation strategies, pulmonary vein (PV) reconnection still occurs in a substantial proportion of patients. The aim of the study was to determine the impact of the elimination of antral low-voltage, fragmented electrograms (LFEGMs) identified by high-density (HD) mapping on the rate of pulmonary vein isolation (PVI) durability.

METHODS

Sixty patients with paroxysmal atrial fibrillation (PAF) were randomly assigned to a verification of PV entrance block and presence of LFEGMs on antral isolation lines with an HD mapping catheter (HD group) or to a verification of PV entrance block with a circumferential mapping catheter alone (CM group). In the HD group, LFEGMs were additionally ablated. Mandatory reassessment procedure to assess PVI durability and the presence of LFEGMs was performed 12 months after the index procedure or earlier in case of arrhythmia recurrence.

RESULTS

A total of 107 out of 116 (92.2%) PVs were found durably isolated in the HD group, and 97 out of 120 (80.8%) PVs in the CM group (p = 0.02). At the reassessment procedure, a total of 7 [3, 12] and 34 [24, 44] LFEGMs were found in the HD and CM groups, respectively (p = 0.00002). Elimination of LFEGMs at the index procedure reduced the likelihood of antral conduction gaps in the same segments at the reassessment. Arrhythmia recurrence rate was similar between the HD and the CM group (7/29, 24.1% vs. 10/30, 33.3%), p = 0.62, respectively.

CONCLUSION

Additional elimination of LFEGMs identified by HD mapping of antral isolation lines after PVI resulted in a significantly higher rate of PVI durability.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: (NCT04466358).

Activation patterns and electrophysiologic characteristics of Marshall bundle-related left atrial tachycardias after atrial fibrillation ablation

BACKGROUND

Epicardial Marshall bundles (MBs) are frequently used in left atrial tachycardias (LATs) after atrial fibrillation (AF) ablation with pulmonary vein isolation and substrate modification.

OBJECTIVE

This study sought to classify different activation patterns of MB-mediated LATs and the corresponding electrophysiologic characteristics.

METHODS

From 2019 to 2021, 28 cases of atrial tachycardias after AF ablation were diagnosed as MB-mediated LATs by ultrahigh-density mapping and entrainment. Cannulation and mapping in the vein of Marshall (VOM) and epicardial mapping in the MB region were also performed in selected cases to further prove the mechanism.

RESULTS

Three activation patterns were identified with a critical isthmus through the MB: perimitral macroreentry (perimitral LAT; n = 20 [71.4%]); left atrial appendage-related reentry (n = 5 [17.9%]); and left pulmonary vein-related reentry (n = 3 [10.7%]). In 18 patients, a characteristic triple potential observed along the previously endocardial left atrial ridge block line was composed of near-field double potentials and far-field MB potential. These findings were further delineated in 24 patients with either cannulation in the VOM (19 patients) or epicardial mapping (5 patients). Ethanol infusion of the VOM resulted in atrial tachycardia termination in 20 of 28 patients.

CONCLUSION

Different types of MB-mediated LATs after AF ablation could be identified by ultrahigh-density mapping. Ethanol infusion within the VOM was effective in eliminating these tachycardias.

High-Resolution Mapping vs Differential Pacing in Evaluating Atrial Linear Lesions and the Impact of Pseudoblocks on AT Risk

BACKGROUND

Although differential pacing (DP) has been conventionally used to confirm the achievement of block across linear lesion sets, high-resolution mapping (HRM)can unmask pseudoblock and persistent residual conduction across the lines.

OBJECTIVES

This study aimed to compare conventional DP criteria with HRM for line assessment and to evaluate the impact of persistent residual conduction across a line on the risk of developing atrial tachycardia (AT) during follow-up.

METHODS

Our study included consecutive patients who underwent AT or persistent atrial fibrillation ablation with ≥1 atrial linear lesion. We systematically evaluated the existence of a residual conduction through all linear lesions using HRM and compared this strategy with the results of DP.

RESULTS

In a cohort of 102 patients, 101 cavotricuspid isthmus lines, 85 roof lines, and 84 mitral isthmus lines were systematically evaluated using DP and HRM. Among the cavotricuspid isthmus lines, 38 lines (37.6%) exhibited residual conduction as determined by HRM. In these 38 cases, DP yielded a false-positive result in 14 cases (37%). For the roof lines, 40 lines (47.1%) showed residual conduction, with DP yielding false-positive results in 16 (40%) of these cases. Regarding the mitral isthmus lines, 24 lines (28.6%) displayed residual conduction, and DP provided false-positive results in 13 (54%) of these cases. The 1-year AT-free survival rate was 95.4% in patients where all attempted lines were successfully blocked, compared to 31.9% in those with ≥1 line that remained unblocked despite multiple ablation attempts.

CONCLUSIONS

The systematic use of HRM for line assessment allows to unmask a substantial proportion of pseudoblocks not identified by DP. The existence of a persistent residual conduction through a line is associated with a high risk of AT during follow-up.

Thermal and Non-Thermal Energies for Atrial Fibrillation Ablation

The cornerstone of ablative therapy for atrial fibrillation (AF) is pulmonary vein isolation (PVI). Whether PVI should be added with additional lesions in persistent atrial fibrillation (PerAF) or for any post-ablative recurrent AF is a matter of debate. Whatever the ablative strategy, it must determine the choice of energy source to achieve the most durable lesion sets with the least likelihood of complications. Radiofrequency (RF) is the most studied thermal ablation technique. It can be combined with high-density electroanatomic mapping and can be used for both pulmonary and extrapulmonary atrial ablation. Cryoenergy is at least as effective as radiofrequency for PVI; it is rapid, relatively safe, and has a steep learning curve. Therefore, it has been proposed as a first-line approach for PVI-only procedures. More recently, a non-thermal technique based on the application of pulsed direct current (Pulsed Field Ablation-PFA) has been introduced. PFA causes cell death by opening cell membrane pores (electroporation) without a significant increase in tissue temperature. It is fast and does not alter the extracellular matrix as thermal techniques do, although it ends up causing long-lasting, transmural lesions. Most importantly, it is relatively selective on cardiac myocytes and therefore potentially safer than thermal techniques. Some PFA systems can be combined with electroanatomic mapping systems. However, as of now, it appears that these ablation technologies should be considered complementary rather than alternative for a number of practical and theoretical reasons.

Catheter Ablation of Atrial Fibrillation: Technique and Future Perspectives

Atrial fibrillation is the most common sustained cardiac arrhythmia with a significant impact on quality of life in terms of symptoms and reduction of functional status. Also, it is associated with an increased risk of mortality, stroke, and peripheral embolism. Catheter ablation for atrial fibrillation has become a well-established treatment, improving arrhythmia outcomes without increasing the risk of serious adverse events compared to antiarrhythmic drug therapy. The field has undergone significant advancements in recent years, yet pulmonary vein isolation continues to be the cornerstone of any atrial fibrillation ablation procedure. The purpose of this review is to provide an overview of the current techniques, emerging technologies, and future directions.

Linear Ablation Using a Contact Force-Sensing Catheter in Ablation for Persistent Atrial Fibrillation: A Prospective Randomized Trial

Background/Objectives: Pulmonary vein isolation (PVI) using radiofrequency catheter ablation with contact force (CF)-sensing technology has improved long-term outcomes in patients with atrial fibrillation. This prospective randomized study aimed to assess the efficacy and safety of CF-sensing technology for additional left atrial (LA) linear ablation of persistent AF (PerAF). Methods: After PVI, anteromitral (AM) line and roof line ablation were performed using a CF-sensing catheter. Patients were randomly assigned to either the CF-sensing (CFS) group or the CF-blind control (Blind) group. The primary endpoint was atrial arrhythmia recurrence. LA late gadolinium enhancement (LA-LGE) MRI was conducted at baseline and 1-year follow-up for long-term lesion evaluation. Results: A total of 62 patients with drug-refractory PerAF were enrolled (mean age: 58 ± 10 years; 77% male). The success rates of AM and roof line block were 97% and 100% in the CFS group (n = 33) and 93% and 90% in the Blind group (n = 29). The time to achieve block was reduced in the CFS group (AM: 36 ± 22 vs. 48 ± 28 min, p = 0.068; roof: 19 ± 14 vs. 27 ± 15 min, p = 0.031). The maximum CF for safety endpoints was significantly lower in the CFS group (AM: 42 vs. 69 g, p < 0.001; roof: 33 vs. 49 g, p = 0.003). Full linear LA-LGE formation on 1-year MRI did not differ significantly between the groups (AM: 17 vs. 36%; roof; 29 vs. 24%, both p = NS). Kaplan-Meier estimates of AF/AT-free survival after ablation procedures were 63.6% in the CFS group and 58.6% in the Blind group (log-rank p = 0.837). Conclusions: In patients with PerAF, additional LA linear ablation following PVI using CF-sensing technology improved procedural safety and reduced the time needed to achieve conduction block. However, it did not significantly influence clinical outcomes or the formation of permanent full linear lesions.

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.

[Initial ablation of atrial fibrillation-Is pulmonary vein isolation sufficient? : Pro and contra]

Pulmonary vein isolation (PVI) is currently the gold standard for the ablation of atrial fibrillation (AF). Although this procedure shows good success rates, the recurrence rates after PVI alone are significantly higher in advanced AF and in the presence of comorbidities. Therefore, it is important to consider additional arrhythmogenic mechanisms outside the pulmonary veins, depending on the individual case, in order to improve the patients' outcome.

Feasibility of atrial linear ablation using a lattice tip catheter that toggles between radiofrequency and pulsed-field energy under deep sedation

BACKGROUND

A novel lattice tip ablation catheter that can toggle between radiofrequency and pulsed-field energy is able to perform not only pulmonary vein isolation, but also linear lesions under general anesthesia (GA).

OBJECTIVE

We aimed to evaluate the concerns associated with the use of deep sedation and the clinical data related to linear ablation.

METHODS

Clinical data from two Germany high-volume atrial fibrillation (AF) centers were collected. The objectives of this study are to confirm the feasibility and safety of linear lesion ablation using the lattice tip catheter without GA. Acute procedural and short-term follow-up data were collected.

RESULTS

This study included 55 patients who underwent AF ablation (15 with GA vs 40 with deep sedation) including linear lesion ablation for atrial tachyarrhythmia using a lattice tip catheter. Bidirectional block of linear lesions was achieved in 21 of 21 linear lesions in the GA and in 74 of 76 (97%) linear lesions in the deep sedation group (P = 1.000) including roof line in 41 of 41 (100%), posterior wall isolation in 4 of 4 (100%), anterior mitral isthmus (MI) line in 5 of 5 (100%) vs 24 of 25 (96%), posterior MI line in 1 of 1 (100%) vs 4 of 5 (80%), cavotricuspid isthmus line in 15 of 15 (100%), and 1 left atrial appendage isolation. The overall incidence rate of complications was 1.8% (1 cardiac tamponade). There was no other procedural related complication.

CONCLUSION

This preliminary clinical study demonstrates feasibility and safety of bidirectional block of linear lesions using a lattice tip catheter under deep sedation. Need to toggle between energy sources was low.

Anatomical Treatment Strategies for Persistent Atrial Fibrillation with Ethanol Infusion within the Vein of Marshall-Current Challenges and Future Directions

Currently, pulmonary vein isolation (PVI) is the gold standard in catheter ablation for atrial fibrillation (AF). However, PVI alone may be insufficient in the management of persistent AF, and complementary methods are being explored. One such method takes an anatomical approach-improving both its success rate and lesion durability may lead to improved treatment outcomes. An additional approach complementary to the anatomical one is also attracting attention, one that focuses on epicardial conduction. This involves ethanol ablation of the vein of Marshall (VOM) and can be very effective in blocking epicardial conduction related to Marshall structure; it is becoming incorporated into standard treatment. However, the pitfall of this "Marshall-PLAN", a method that combines an anatomical approach with ethanol infusion within the VOM (Et-VOM), is that Et-VOM and other line creations are not always successfully completed. This has led to cases of AF and/or atrial tachycardia (AT) recurrence even after completing this lesion set. Investigating effective adjunctive methods will enable us to complete the lesion set with the aim to lower the rates of recurrence of AF and/or AT in the future.

Automatic identification of ablation targets in persistent atrial fibrillation: Initial experience with a new mapping tool

INTRODUCTION

Strategies beyond pulmonary vein isolation (PVI) in persistent atrial fibrillation (persAF) are debated. A novel mapping tool provides algorithmic detection of ablation targets based on electrogram (EGM) properties specific to stable localized rotational activations.

METHODS

The mapping tool was used on 31 patients (20 de novo). The algorithm was used to optimize PVI line placement and guide additional ablations. Targets were detected by calculating local cycle length (L-CL) and local spread of activation within that L-CL (Duty Cycle; DC) for EGMs with consistent morphology and activation. At least two left atrial (LA) maps (pre-PVI and post-PVI) were acquired in atrial fibrillation (AF) in all patients (except those with AF termination during PVI). Extra-pulmonary vein (PV) targets were compared between the two LA maps in each patient. Follow-up included Holter monitoring every 3 months.

RESULTS

Patients had a median of 3 extra-PV drivers/targets. The majority (81%) were localized in the same areas between the two LA maps. All patients had progressive AF organization demonstrated by global activation slowing: histogram peak L-CL increased from 162 to 171 ms (post-PVI; p = .0003) than to 175 ms (posttarget ablation; p = .04). Moreover, L-CL dispersion was reduced by ablation; in 50% their values tended to cluster around two dominant cycles. In de novo patients AF terminated to sinus rhythm or atrial tachycardia (AT) within 48 h postprocedure in 88% of cases, and at 18 months mean follow-up recurrence occurred in only five (25%) patients (three persAF, two AT). There were no complications.

CONCLUSION

The algorithmic detection of EGMs consistent with localized reentry during sequential mapping of persAF provided reproducible targets for ablation. This allowed personalized PVI and limited, highly-selective, extra-PV ablation. Results of this initial experience included progressive organization of AF with ablation and a low recurrence rate after a single procedure.

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.

Risk assessment of esophageal ulceration following left atrial radiofrequency linear ablation

INTRODUCTION

Esophageal safety following radiofrequency (RF) left atrial (LA) linear ablation has not been established. To determine the esophageal safety profile of LA linear RF lesions, we performed systematic esophagogastroduodenoscopy in all patients with intraesophageal temperature rise (ITR) ≥ 38.5°C.

METHODS AND RESULTS

Between December 2021 and July 2023, a total of 200 consecutive patients with atrial tachyarrhythmia (ATA) underwent linear ablation with posterior dome (roof or floor) or posterior mitral isthmus line transection. Patients with ITR ≥ 38.5°C were scheduled for esophageal endoscopy ~3 weeks after ablation. Patient and ATA characteristics, procedural parameters, endoscopy findings and ablation lesion data were collected and analyzed. One hundred thirty-three out of 200 (67%) patients showed ITR ≥ 38.5°C during LA linear ablation. ITR (with maximal temperature of 45.7°C) was more frequently observed during floor line ablation (82% of cases). ITR was less observed during roof line ablation (34%) and posterior mitral isthmus ablation (4%). Endoscopy, performed in 115 patients after 24 ± 10 days, showed esophageal ulceration in four patients (two patients Kansas City classification [KCC] 2a and two patients KCC 2b). No patient showed esophageal perforation or fistula.

CONCLUSION

Temperature rise during LA linear ablation is frequent and ulceration risk exists, particularly when floor line is performed. Safety measures are needed to avoid potential severe complications like esophageal perforation and fistula.

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.

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 .