Electrical Posterior Box Isolation in Repeat Ablation for Atrial Fibrillation: A Prospective Randomized Clinical Study

Repeat catheter ablation for atrial fibrillation

Catheter ablation of atrial fibrillation (AF) is an established therapy that reduces AF burden, improves quality of life, and reduces the risks of cardiovascular outcomes. Although there are clear guidelines for the application of de novo catheter ablation, there is less evidence to guide recommendations for repeat catheter ablation in patients who experience recurrent AF. In this review, we examine the rationale for repeat ablation, mechanisms of recurrence, patient selection, optimal timing, and procedural strategies. We discuss additional important considerations, including treatment of comorbidities and risk factors, risk of complications, and effectiveness. Mechanisms of recurrent AF are often due to non-pulmonary vein (non-PV) triggers; however, there is insufficient evidence supporting the routine use of empiric lesion sets during repeat ablation. The emergence of pulsed field ablation may alter the safety and effectiveness of de novo and repeat ablation. Extrapolation of data from randomized trials of de novo ablation does not optimally inform efficacy in cases of redo ablation. Additional large, randomized controlled trials are needed to address important clinical questions regarding procedural strategies and timing of repeat ablation.

Pulmonary Vein Isolation Followed by Biatrial Ablation of Rotational Activity in Patients with Persistent Atrial Fibrillation: Results of the Cryo-Vest Study

Background and Aims: Noninvasive mapping allows the identification of patient-specific atrial rotational activity (RA) that might play a key role in the perpetuation of persistent atrial fibrillation (PsAF). So far, the impact of pulmonary vein isolation by cryoballoon (Cryo-PVI) on RA is unclear. Moreover, the long-term effect of periprocedural termination of AF during the ablation procedure is controversial. Methods: Noninvasive electrocardiographic mapping with a 252-electrode vest was performed in 42 patients with PsAF. After the first analysis, Cryo-PVI was performed. The RA was analyzed again and then targeted by radiofrequency catheter ablation. The primary clinical endpoint was periprocedural termination of AF. The secondary endpoint was freedom from any atrial arrhythmia >30 s during a 12-month follow-up. Results: In 33 patients (79%), right atrial RA was identified leading to biatrial ablation, and nine patients (21%) had left atrial RA only. Twelve patients (28.6%) converted from AF to sinus rhythm (SR) (Group A). Thirteen patients (30.9%) converted to atrial tachycardia (AT) (Group B). In 17 patients (40.5%), AF was not terminated by ablation (Group C). After a mean follow-up time of 13.8 months, 26 patients were free from AF and AT (61.9%). In terms of rhythm, control Group A (75%) and B (83.3%) showed higher success rates than Group C (33.3%) (p < 0.01). Cryo-PVI had no substantial impact on RA. Conclusions: The RA-based ablation approach showed acceptable success rates. Periprocedural termination of AF had a positive predictive impact on the outcome. No difference was observed between conversion to SR or to AT. Cryo-PVI had no impact on RA.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Box Lesion Isolation of the Left Atrial Posterior Wall with Radiofrequency Ablation Restricted in Predetermined Lines for the Treatment of Persistent Atrial Fibrillation: The Prognostic Role of Acute Interventional Outcome and Trigger Identification

The left atrial posterior wall (PW) is known to be a critical substrate for the initiation and perpetuation of atrial fibrillation (AF) and has been explored as a target for catheter ablation, particularly in persistent AF (PerAF). In this retrospective study, we investigate the clinical outcome of patients with PerAF who underwent PW isolation (PWI) restricted in predetermined lines in addition to pulmonary vein isolation (PVI). One hundred consecutive patients (64 ± 9.1 years, 66% male, 20% with previous PVI ablation) underwent PWI in a box lesion setting for PerAF lasting >3 months (34% long-standing PerAF). PW triggers were defined as either foci from the PW that repeatedly induced AF or as isolated AF or atrial tachycardia (AT) within the PW. After a mean follow-up period of 25.6 ± 6.7 months, 61% of the patients remained in sinus rhythm after the last procedure. In 79 patients, the PW was successfully isolated, while, in 21 patients, complete isolation was not possible due to failure in completion of the roof line (n = 16), the floor line (n = 7), or both (n = 2). Patients with incomplete isolation had similar AF/AT recurrence rates compared to those with complete PWI. In 12 patients, PW triggers were identified, and PWI in these patients was shown to have a significantly better prognosis in terms of sinus rhythm maintenance (P = .031). Failure of complete PWI does not predispose a patient to an inferior outcome nor is it responsible for iatrogenic ATs. The presence of AF triggers within the PW leads to a particularly favorable result after box lesion isolation.

Safety and Effectiveness of Adjunctive Posterior Wall Isolation in Atrial Fibrillation Patients: An Updated Meta-Analysis

As the atrial fibrillation (AF) recurrence rate remains high after pulmonary vein isolation (PVI), additional left atrial posterior wall isolation (PWI) has been studied in randomized controlled trials, however, the results are conflicting. We performed an updated meta-analysis by searching online databases for the randomized controlled trials comparing the PWI + PVI group to the PVI alone group in patients with AF. The outcomes of interest were AF recurrence, all atrial arrhythmia recurrence, and atrial flutter/atrial tachycardia (AT) recurrence. Risk ratio (RR) with a 95% confidence interval (CI) was estimated using a random effects model. A total of 1,612 patients, with 807 in the PWI + PVI group and 805 in the PVI alone group were included. The mean age was 60 (9) years, 75% were men and 71% had persistent AF. The PWI + PVI group had lower AF recurrence as compared with the PVI alone group (25% vs 32%, RR 0.73, 95% CI 0.56 to 0.96, p = 0.02). There were no significant differences in all atrial arrhythmia recurrence (RR 0.90, 95% CI 0.78 to 1.04, p = 0.16), atrial flutter/AT recurrence (RR 1.19, 95% CI 0.92 to 1.55, p = 0.19) or adverse event rates in the 2 groups (36 vs 31; RR 1.09, 95% CI 0.67 to 1.77, p = 0.73). In conclusion, adjunctive PWI in addition to PVI can be achieved with lower AF recurrence but with a nonsignificant increase in atrial flutter/AT recurrence, resulting in an overall similar rate of all atrial arrhythmia recurrence without increasing the risk of adverse events, when compared with PVI alone strategy.

Temporal Trends and Lesion Sets for Persistent Atrial Fibrillation Ablation: A Meta-Analysis With Trial Sequential Analysis and Meta-Regression

BACKGROUND

Ablation for persistent atrial fibrillation (PsAF) has been performed for over 20 years, although success rates have remained modest. Several adjunctive lesion sets have been studied but none have become standard of practice. We sought to describe how the efficacy of ablation for PsAF has evolved in this time period with a focus on the effect of adjunctive ablation strategies.

METHODS

Databases were searched for prospective studies of PsAF ablation. We performed meta-regression and trial sequential analysis.

RESULTS

A total of 99 studies (15 424 patients) were included. Ablation for PsAF achieved the primary outcome (freedom of atrial fibrillation/atrial tachycardia rate at 12 months follow-up) in 48.2% (5% CI, 44.0-52.3). Meta-regression showed freedom from atrial arrhythmia at 12 months has improved over time, while procedure time and fluoroscopy time have significantly reduced. Through the use of cumulative meta-analyses and trial sequential analysis, we show that some ablation strategies may initially seem promising, but after several randomized controlled trials may be found to be ineffective. Trial sequential analysis showed that complex fractionated atrial electrogram ablation is ineffective and further study of this treatment would be futile, while posterior wall isolation currently does not have sufficient evidence for routine use in PsAF ablation.

CONCLUSIONS

Overall success rates from PsAF ablation and procedure/fluoroscopy times have improved over time. However, no adjunctive lesion set, in addition to pulmonary vein isolation, has been conclusively demonstrated to be beneficial. Through the use of trial sequential analysis, we highlight the importance of adequately powered randomized controlled trials, to avoid reaching premature conclusions, before widespread adoption of novel therapies.

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.

Hybrid atrial fibrillation ablation: long-term outcomes from a single-centre 10-year experience

AIMS

Hybrid atrial fibrillation (AF) ablation is a promising approach in non-paroxysmal AF. The aim of this study is to assess the long-term outcomes of hybrid ablation in a large cohort of patients after both an initial and as a redo procedure.

METHODS AND RESULTS

All consecutive patients undergoing hybrid AF ablation at UZ Brussel from 2010 to 2020 were retrospectively evaluated. Hybrid AF ablation was performed in a one-step procedure: (i) thoracoscopic ablation followed by (ii) endocardial mapping and eventual ablation. All patients received PVI and posterior wall isolation. Additional lesions were performed based on clinical indication and physician judgement. Primary endpoint was freedom from atrial tachyarrhythmias (ATas). A total of 120 consecutive patients were included, 85 patients (70.8%) underwent hybrid AF ablation as first procedure (non-paroxysmal AF 100%), 20 patients (16.7%) as second procedure (non-paroxysmal AF 30%), and 15 patients (12.5%) as third procedure (non-paroxysmal AF 33.3%). After a mean follow-up of 62.3 months ± 20.3, a total of 63 patients (52.5%) experienced ATas recurrence. Complications occurred in 12.5% of patients. There was no difference in ATas between patients undergoing hybrid as first vs. redo procedure (P = 0.53). Left atrial volume index and recurrence during blanking period were independent predictors of ATas recurrence.

CONCLUSION

In a large cohort of patients undergoing hybrid AF ablation, the survival from ATas recurrence was 47.5% at ≈5 years follow-up. There was no difference in clinical outcomes between patients undergoing hybrid AF ablation as first procedure or as a redo.

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.

Ganglionic Plexus Ablation: A Step-by-step Guide for Electrophysiologists and Review of Modalities for Neuromodulation for the Management of Atrial Fibrillation

As the most common sustained arrhythmia, AF is a complex clinical entity which remains a difficult condition to durably treat in the majority of patients. Over the past few decades, the management of AF has focused mainly on pulmonary vein triggers for its initiation and perpetuation. It is well known that the autonomic nervous system (ANS) has a significant role in the milieu predisposing to the triggers, perpetuators and substrate for AF. Neuromodulation of ANS - ganglionated plexus ablation, vein of Marshall ethanol infusion, transcutaneous tragal stimulation, renal nerve denervation, stellate ganglion block and baroreceptor stimulation - constitute an emerging therapeutic approach for AF. The purpose of this review is to summarise and critically appraise the currently available evidence for neuromodulation modalities in AF.

Percutaneous Treatment Approaches in Atrial Fibrillation: Current Landscape and Future Perspectives

Atrial fibrillation (AF), the most common sustained arrhythmia in clinical practice, represents a major cause of morbidity and mortality, with an increasing prevalence. Pharmacologic treatment remains the cornerstone of its management through rhythm and rate control, as well as the prevention of thromboembolism with the use of oral anticoagulants. Recent progress in percutaneous interventional approaches have provided additional options in the therapeutic arsenal, however. The use of the different catheter ablation techniques can now lead to long arrhythmia-free intervals and significantly lower AF burden, thus reducing the rate of its complications. Particularly encouraging evidence is now available for patients with persistent AF or concomitant heart failure, situations in which catheter ablation could even be a first-line option. In the field of stroke prevention, targeting the left atrial appendage with percutaneous device implantation may reduce the risk of thromboembolism to lower rates than that predicted with conventional ischemic risk scores. Left atrial appendage occlusion through the approved Watchman or Amplatzer devices is a well-established, efficacious, and safe method, especially in high-ischemic and bleeding risk patients with contraindications for oral anticoagulation.

Mapping Atrial Fibrillation After Surgical Therapy to Guide Endocardial Ablation

BACKGROUND

Surgical ablation for atrial fibrillation (AF) can be effective, yet has mixed results. It is unclear which endocardial lesions delivered as part of hybrid therapy' will best augment surgical lesion sets in individual patients. We addressed this question by systematically mapping AF endocardially after surgical ablation and relating findings to early recurrence, then performing tailored endocardial ablation as part of hybrid therapy.

METHODS

We studied 81 consecutive patients undergoing epicardial surgical ablation (stage 1 hybrid), of whom 64 proceeded to endocardial catheter mapping and ablation (stage 2). Stage 2 comprised high-density mapping of pulmonary vein (PV) or posterior wall (PW) reconnections, low-voltage zones (LVZs), and potential localized AF drivers. We related findings to postsurgical recurrence of AF.

RESULTS

Mapping at stage 2 revealed PW isolation reconnection in 59.4%, PV isolation reconnection in 28.1%, and LVZ in 42.2% of patients. Postsurgical recurrence of AF occurred in 36 patients (56.3%), particularly those with long-standing persistent AF (P=0.017), but had no relationship to reconnection of PVs (P=0.53) or PW isolation (P=0.75) when compared with those without postsurgical recurrence of AF. LVZs were more common in patients with postsurgical recurrence of AF (P=0.002), long-standing persistent AF (P=0.002), advanced age (P=0.03), and elevated CHA₂DS₂-VASc (P=0.046). AF mapping revealed 4.4±2.7 localized focal/rotational sites near and also remote from PV or PW reconnection. After ablation at patient-specific targets, arrhythmia freedom at 1 year was 81.0% including and 73.0% excluding previously ineffective antiarrhythmic medications.

CONCLUSIONS

After surgical ablation, AF may recur by several modes particularly related to localized mechanisms near low voltage zones, recovery of posterior wall or pulmonary vein isolation, or other sustaining mechanisms. LVZs are more common in patients at high clinical risk for recurrence. Patient-specific targeting of these mechanisms yields excellent long-term outcomes from hybrid ablation.

Anti-atrial Fibrillation Effects of Pulmonary Vein Isolation With or Without Ablation Gaps: A Computational Modeling Study

Background

Although pulmonary vein isolation (PVI) gaps contribute to recurrence after atrial fibrillation (AF) catheter ablation, the mechanism is unclear. We used realistic computational human AF modeling to explore the AF wave-dynamic changes of PVI with gaps (PVI-gaps).

Methods

We included 40 patients (80% male, 61.0 ± 9.8 years old, 92.5% persistent AF) who underwent AF catheter ablation to develop our realistic computational AF model. We compared the effects of a complete PVI (CPVI) and PVI-gap (2-mm × 4) on the AF wave-dynamics by evaluating the dominant frequency (DF), spatial change of DF, maximal slope of the action potential duration restitution curve (Smax), and AF defragmentation rate (termination or change to atrial tachycardia), and tested the effects of additional virtual interventions and flecainide on ongoing AF with PVI-gaps.

Results

Compared with the baseline AF, CPVIs significantly reduced extra-PV DFs (p < 0.001), but PVI-gaps did not. COV-DFs were greater after CPVIs than PVI-gaps (p < 0.001). Neither CPVIs nor PVI-gaps changed the mean Smax. CPVIs resulted in higher AF defragmentation rates (80%) than PVI-gaps (12.5%, p < 0.001). In ongoing AF after PVI-gaps, the AF defragmentation rates after a wave-breaking gap ablation, extra-PV DF ablation, or flecainide were 60.0, 34.3, and 25.7%, respectively (p = 0.010).

Conclusion

CPVIs effectively reduced the DF, increased its spatial heterogeneity in extra-PV areas, and offered better anti-AF effects than extra-PV DF ablation or additional flecainide in PVI-gap conditions.