The effect of posterior wall isolation for persistent atrial fibrillation on recurrent arrhythmia

Safety and effectiveness of additional left atrial posterior wall ablation using pulsed field ablation for persistent and long-standing persistent atrial fibrillation patients

INTRODUCTION

The unique safety profile of pulsed field ablation (PFA) has made pulmonary vein isolation (PVI) + left atrial posterior wall (LAPW) ablation promising for treating persistent atrial fibrillation (PerAF). The goal of this study was to assess long-term freedom from atrial fibrillation, atrial flutter, and atrial tachycardia (AF/AFL/AT), as well as the safety and feasibility of LAPW PFA using multipolar, pentaspline Farawave catheter.

METHODS

Retrospective observational study at a single institution. Data for 94 patients were collected from a prespecified intraprocedural registry. The long-term AF/AFL/AT recurrence assessment was based on an analysis of medical history; 24-h Holter ECGs at 3, 6, and 12 months postablation; and 12-lead ECGs recorded during symptomatic episodes or visits.

RESULTS

Half of the patients had ls-PerAF, and half had a history of catheter ablation-mostly RF PVI. The acute ablation success rate was 100%, and the primary safety outcome was observed in 2 patients. Fifty patients experienced AF/AFL/AT recurrence (54.3%). An increase in LAPW low-voltage areas and AF classification were associated with arrhythmia recurrence. After a median follow-up of 13 months, the Kaplan‒Meier estimated median time free of AF/AFL/AT after a single procedure was 14.7 months.

CONCLUSION

PFA PVI + PWA had the best outcome in perAF patients without extensive LA fibrosis. AF recurrence was paroxysmal in significant part of the cohort. The addition of PWA to PVI using multipolar PFA was safe and did not significantly influence the transpired ablation time.

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 .

High-Power Short-Duration Lesion Index-Guided Posterior Wall Isolation beyond Pulmonary Vein Isolation for Persistent Atrial Fibrillation

Background: High-power short-duration (HPSD) radiofrequency (RF) ablation has been adopted to improve atrial fibrillation (AF) ablation. Although the role of HPSD is well-established in pulmonary vein isolation (PVI), fewer data have assessed the impact of HPSD when addressing extra-pulmonary veins (PVs) targets. Therefore, this study aims to determine the safety, effectiveness, and acute outcomes of HPSD lesion index (LSI)-guided posterior wall isolation (PWI) in addition to PVI as an initial strategy in persistent atrial fibrillation (Pe-AF). Methods: Consecutive patients who underwent ablation of Pe-AF in our center between August 2021 and January 2022 were retrospectively enrolled. All patients' ablation strategy was PVI plus PWI using HPSD LSI-guided isolation. RF parameters included 50 W targeting LSI values of ≥5 on the anterior part of the PVs and anterior roofline and ≥4 for the posterior PVs aspect, bottom line, and within the posterior wall (PW). We compared the LSI values with and without acute conduction gaps after the initial first-pass PWI. Left atrial mapping was performed with the EnSite X mapping system and a high-density multipolar Grid-shaped mapping catheter. We compared the procedural characteristics using HPSD (n = 35) vs. a control group (n = 46). Results: Thirty-five consecutive patients were included in the study. PWI on top of PVI was achieved in all cases in the HPSD group. First-pass PVI was achieved in 93.3% of PVs (n = 126/135). First-pass roofline block was obtained in most patients (n = 31, 88.5%), while first-pass block of the bottom line was only achieved in 51.4% (n = 18). There were no significant differences compared to the control group; first-pass PVI was achieved in 94.9% of PVs (n = 169/178), first-pass roofline block in 89.1%, and bottom-line in 45.6% of patients. To achieve complete PWI with HPSD, scattered RF applications within the PW were necessary. No electrical reconnection of the PW was found after adenosine administration and the waiting period. The procedure and RF times were significantly shorter in the HPSD group compared to the control group, with values of 116.2 ± 10.9 vs. 144.5 ± 11.3 min, and 19.8 ± 3.6 vs. 26.3 ± 6.4 min, respectively, p < 0.001. Fluoroscopy time was comparable between both groups. No procedural complications were observed. At the 12-month follow-up, 71.4% of patients remained free from AF, with no differences between the groups. Conclusions: HPSD LSI-guided PWI on top of PVI seems effective and safe. Compared to a control group, HPSD is associated with similar rates of first-pass PWI and PVI but with a shorter procedural and RF time.

Association between residual unipolar voltage and arrhythmia recurrence after left atrial posterior wall isolation for persistent atrial fibrillation

INTRODUCTION

Posterior wall isolation (PWI) combined with pulmonary vein isolation (PVI) has proven effective for persistent atrial fibrillation (AF). However, when performing PWI, creating transmural lesions with subendocardial ablation is sometimes difficult. Endocardial unipolar voltage amplitude had a higher sensitivity than bipolar voltage mapping for identifying intramural viable myocardium in the atria. In this study, we aimed to retrospectively investigate the correlation between the residual potential in the posterior wall (PW) following PWI for persistent AF and atrial arrhythmia recurrence using endocardial unipolar voltage.

METHODS

This was a single-center observational study. Patients who underwent PVI and PWI for persistent AF in the first procedure between March 2018 and December 2021 at the Tokyo Metropolitan Hiroo Hospital were included in this study. The patients were divided into two groups based on the presence of residual unipolar PW potentials after PWI with a cutoff of 1.08 mV and the recurrence of atrial arrhythmias was compared.

RESULTS

In total, 109 patients were included in the analysis. Forty-three patients had residual unipolar potentials after PWI and 66 patients had no residual unipolar potentials. The atrial arrhythmia recurrence rate was significantly higher in the group with residual unipolar potential (41.8% vs. 17.9%, p = 0.003). The residual unipolar potential was an independent predictor of recurrence (odds ratio: 4.53; confidence interval: 1.67-12.3, p = 0.003).

CONCLUSION

Residual unipolar potential after PWI for persistent AF is associated with recurrent atrial arrhythmias.

Extensive Posterior Wall Isolation on Top of Pulmonary Vein Isolation Guided by Ablation Index in Persistent Atrial Fibrillation Ablation

Background: Durable pulmonary vein isolation (PVI) is recommended for symptomatic paroxysmal atrial fibrillation (AF) treatment, but it has been demonstrated that it may not be enough to treat persistent AF (Pe-AF). Therefore, posterior wall isolation (PWI) is among the strategies adopted on top of PVI to treat Pe-AF patients. However, PWI using contiguous and optimized radiofrequency lesions remains challenging, and few studies have evaluated the impact of the Ablation Index (AI) on the efficacy of PWI. Moreover, previous papers did not evaluate arrhythmia recurrences using continuous monitoring. Methods: This is a prospective, observational, single-center study on patients affected by Pe-AF undergoing treated PVI plus AI-guided PWI. Procedures were performed using the CARTO mapping system, SmartTouch SF ablation catheter, and PentaRay multipolar mapping catheter. The AI settings were 500–550 for the anterior PV aspect and roofline, while the settings were 450–500 for the posterior PV aspect, bottom line, and/or PW lesions. All patients received an implantable loop recorder (ILR). All patients underwent clinical evaluation in the outpatient clinic at 1, 3, 6, 12, 18, and 24 months. A standard 12-lead ECG was performed at each visit, and device data from the ILR were reviewed to assess for arrhythmia recurrence. Results: Between January 2021 and December 2021, forty-one consecutive patients underwent PVI plus PWI guided by AI at our center and were prospectively enrolled in the study. PVI was achieved in all patients, first-pass roofline block was obtained in 82.9% of the patients, and first-pass block of the bottom line was achieved in 36.5% of the patients. In 39% of the patients, PWI was not performed with a “box-only” lesion set, but with scattered lesions across the PW to achieve PWI. AI on the anterior aspect of the left PVs was 528 ± 22, while on the posterior aspect of the left PVs, it was 474 ± 18; on the anterior aspect of the right PVs, it was 532 ± 27, while on the posterior aspect of the right PVs, it was 477 ± 16; on the PW, AI was 468 ± 19. No acute complications occurred at the end of the procedure. After the blanking period, 70.7% of the patients reported no arrhythmia recurrence during the 12-month follow-up period. Conclusions: In patients with Pe-AF undergoing catheter ablation, PWI guided by AI seems to be an effective and feasible strategy in addition to standard PVI.

Comparing the efficacy of catheter ablation strategies for persistent atrial fibrillation: a Bayesian analysis of randomized controlled trials

BACKGROUND

Catheter ablation has been recommended as the first-line treatment option for selected patients with atrial fibrillation (AF). However, a widely accepted ablation strategy for persistent AF (perAF) has not yet been established. The benefits of ablation strategies are not conclusive for perAF. There is an urgent need to systematically analyze the results of previous studies and rank these treatment strategies to guide clinical practice.

METHODS

Randomized controlled trials (RCTs) on ablation for perAF were included. The primary outcome was recurrence of atrial tachyarrhythmia (AT) after a single ablation procedure. A Bayesian random-effects network meta-analysis model was fitted.

RESULTS

Twenty-three studies were included in the analysis. A total of 3394 patients and 22 ablation strategies were found in the involved studies. The ablation strategy of pulmonary vein isolation (PVI) + electrical box isolation of the left atrial posterior wall (PBOX) + non-PV trigger ablation (NPV) showed the best treatment effect in terms of the primary outcome. The individualized ablation strategies of mapping and ablation combined with PVI, such as PVI + rotors, PVI + dispersion areas, and PVI + low voltage zone (LVZ) also showed a better ablation effect in perAF.

CONCLUSIONS

PVI ablation is a widely used strategy in perAF and is recognized as a cornerstone procedure for perAF. The PVI + PBOX + NPV strategy showed the highest rank in our analysis. Mapping and ablation strategies that could provide individualized substrate modification also showed a better rank in our analysis and are believed to be a promising direction for the treatment of perAF.

Atrial Fibrillation Global Changes after Pulmonary Vein and Posterior Wall Isolation: A Charge Density Mapping Study

Background: Non-contact charge density (CD) mapping allows a global visualization of left atrium (LA) activation and of activation patterns during atrial fibrillation (AF). The aim of this study was to analyze, with CD mapping, the changes in persistent AF induced by pulmonary vein isolation (PVI) and LA posterior wall isolation (LAPWI). Methods: Patients undergoing PVI + LAPWI using the Arctic Front Advance PRO^TM cryoballoon system were included in the study. CD maps were created during AF at baseline, after PVI and after LAPWI. Three distinct activation patterns were identified in the CD maps: localized irregular activation (LIA), localized rotational activation (LRA) and focal centrifugal activation (FCA). LA maps were divided into the following regions: anterior, septal, lateral, roof, posterior, inferior. Results: Eleven patients were included, with a total of 33 maps and 198 AF regions analyzed. Global and regional AF cycle lengths significantly increased after PVI and LAPWI. Baseline analysis demonstrated higher LIA, LRA and FCA numbers in the posterior and anterior regions. After PVI, there was no change in LIA, LRA and FCA occurrence. After PVI + LAPWI, a significant decrease in LRA was observed with no difference in LIA and FCA occurrence. In the regional analysis, there was a significant reduction in the LIA number in the inferior region, in the LRA number in the roof and posterior regions and in the FCA number in the lateral region. Conclusions: A global reduction in the LRA number was observed only after PVI + LAPWI; it was driven by a reduction in rotational activity in the roof and posterior regions.

Adjunctive Left Atrial Posterior Wall Isolation in Treating Atrial Fibrillation: Insight From a Large Secondary Analysis

OBJECTIVES

This study evaluated the role of adjunctive left atrium posterior wall isolation (PWI) in preventing atrial fibrillation (AF) recurrence.

BACKGROUND

The left atrium posterior wall is an arrhythmogenic substrate that contributes to the development of AF.

METHODS

This was an updated pooled analysis that included clinical data regarding PWI plus pulmonary vein isolation (PVI) in treating AF. The primary outcome was recurrence of atrial tachyarrhythmias.

RESULTS

A total of 26 studies with 3,287 patients with AF (age 61.7 ± 10.8 years) were included. Mean follow-up was 15.2 ± 8.4 months. Procedural success to achieve PWI was 92.8%. In paroxysmal AF, adjunctive PWI did not reduce the recurrence of all atrial arrhythmias (P = 0.21) or AF (P = 0.37); however, in persistent AF, adjunctive PWI was associated with substantially lower recurrence of all atrial arrhythmias (risk ratio: 0.74; P < 0.001) and AF (risk ratio: 0.67; P = 0.01), particularly when randomized data were included. Subgroup analyses based on meta-regression demonstrated that patients with older age, a larger left atrial diameter, and persistent AF benefited more significantly from the adjunctive PWI. Adjunctive PWI using either radiofrequency or a cryoballoon reduced AF recurrence, whereas using radiofrequency seemed to be associated with higher recurrence rate of atrial tachycardias and/or atrial flutter. Non-BOX adjunctive PWI rather than BOX PWI was associated with significantly lower recurrence of AF. The incidence of procedural adverse events between the PVI+PWI (3.2%) and PVI (2.8%) groups was low and similar. PVI+PWI needed longer ablation and/or procedural time but had similar fluoroscopy time.

CONCLUSIONS

Adjunctive PWI can be achieved in most patients without compromising safety. Patients with persistent AF appear to benefit from this approach. The ablation technology and/or approach may affect the clinical outcome of PWI.

Catheter ablation for persistent atrial fibrillation: A multicenter randomized trial of pulmonary vein isolation (PVI) versus PVI with posterior left atrial wall isolation (PWI) - The CAPLA study

BACKGROUND

The success of pulmonary vein isolation (PVI) is reduced in persistent AF (PsAF) compared to paroxysmal AF. Adjunctive ablation strategies have failed to show consistent incremental benefit over PVI alone in randomized studies. The left atrial posterior wall is a potential source of non-PV triggers and atrial substrate which may promote the initiation and maintenance of PsAF. Adding posterior wall isolation (PWI) to PVI had shown conflicting outcomes, with earlier studies confounded by methodological limitations.

OBJECTIVES

To determine whether combining PWI with PVI significantly improves freedom from AF recurrence, compared to PVI alone, in patients with PsAF.

METHODS

This is a multi-center, prospective, international randomized clinical trial. 338 patients with symptomatic PsAF refractory to anti-arrhythmic therapy (AAD) will be randomized to either PVI alone or PVI with PWI in a 1:1 ratio. PVI involves wide antral circumferential pulmonary vein (PV) isolation, utilizing contact force sensing ablation catheters. PWI involves the creation of a floor line connecting the inferior aspect of the PVs, and a roof line connecting the superior aspect of the PVs. Follow up is for a minimum of 12 months with rhythm monitoring via implantable cardiac device and/or loop monitor, or frequent intermittent monitoring with an ECG device. The primary outcome is freedom from any documented atrial arrhythmia of > 30 seconds off AAD at 12 months, after a single ablation procedure.

CONCLUSIONS

This randomized study aims to determine the success and safety of adjunctive PWI to PVI in patients with persistent AF.

Persistent Atrial Fibrillation: The Role of Left Atrial Posterior Wall Isolation and Ablation Strategies

Atrial fibrillation (AF) is a global disease with rapidly rising incidence and prevalence. It is associated with a higher risk of stroke, dementia, cognitive decline, sudden and cardiovascular death, heart failure and impairment in quality of life. The disease is a major burden on the healthcare system. Paroxysmal AF is typically managed with medications or endocardial catheter ablation to good effect. However, a large proportion of patients with AF have persistent or long-standing persistent AF, which are more complex forms of the condition and thus more difficult to treat. This is in part due to the progressive electro-anatomical changes that occur with AF persistence and the spread of arrhythmogenic triggers and substrates outside of the pulmonary veins. The posterior wall of the left atrium is a common site for these changes and has become a target of ablation strategies to treat these more resistant forms of AF. In this review, we discuss the role of the posterior left atrial wall in persistent and long-standing persistent AF, the limitations of current endocardial-focused treatment strategies, and future perspectives on hybrid epicardial–endocardial approaches to posterior wall isolation or ablation.

The role of posterior wall isolation in catheter ablation of persistent atrial fibrillation

The left atrial posterior wall has many embryologic, anatomic, and electrophysiologic characteristics, that are important for the initiation and maintenance of persistent atrial fibrillation. The left atrial posterior wall is a potential target for ablation in patients with persistent atrial fibrillation, a population in whom pulmonary vein isolation alone has resulted in unsatisfactory recurrence rates. Published clinical studies report conflicting results on the safety and efficacy of posterior wall isolation. Emerging technologies including optimized use of radiofrequency ablation, pulse field ablation, and combined endocardial/epicardial ablation may optimize approaches to posterior wall isolation and reduce the risk of injury to nearby structures such as the esophagus. Critical evaluation of future and ongoing clinical studies of posterior wall isolation requires careful scrutiny of many characteristics, including intraprocedural definition of posterior wall isolation, concomitant extrapulmonary vein ablation, and study endpoints.