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

Evaluating the Effectiveness of Combined Left Atrial Posterior Wall Linear Ablation and Pulmonary Vein Isolation in Reducing Long-Term Recurrence Rates After Surgery in Patients with Persistent Atrial Fibrillation: A Randomized Controlled Trial

PURPOSE

This study aimed to evaluate whether combining left atrial posterior wall linear ablation with PVI (LAPVI) improves long-term outcomes in patients with persistent AF.

METHODS

In a randomized controlled trial, 228 patients with persistent AF underwent PVI and were randomly assigned to either receive additional LAPVI or not. Procedures used a standardized protocol under general anesthesia. Outcomes, including sinus rhythm maintenance and recurrence rates of AF, were assessed at 6 months, 1 year, and 2 years post-procedure. Statistical analysis was performed using the chi-square test for categorical variables and t-tests for continuous variables.

RESULTS

At 2 years, 74.77% of the LAPVI group maintained sinus rhythm compared to 54.7% in the PVI group (P = 0.002). Recurrence rates of paroxysmal and persistent AF were significantly lower in the LAPVI group at 11.71% and 9.01%, respectively, versus 24.79% and 20.51% in the PVI group (P < 0.05). Antiarrhythmic drug use was significantly reduced in the LAPVI group at each follow-up interval (P < 0.05).

CONCLUSION

LAPVI significantly enhances long-term rhythm control and reduces dependence on antiarrhythmic drugs compared to PVI alone in patients with persistent AF.

Adjunctive Left Atrial Posterior Wall Isolation in Treating Non-Paroxysmal Atrial Fibrillation: An Updated Meta-Analysis of Randomized Clinical Trials

BACKGROUND

The clinical outcomes of adjunctive posterior wall isolation (PWI) beyond pulmonary vein isolation (PVI) for non-paroxysmal atrial fibrillation (AF) remain unclear. This meta-analysis was conducted to evaluate the role of PWI in non-paroxysmal AF by pooled analysis of most updated randomized controlled trials (RCTs).

METHODS

A literature search in PubMed, Embase, and the Cochrane Library was performed to identify RCTs comparing the outcomes of PVI with and without PWI in non-paroxysmal AF patients. The primary outcomes were recurrence rates of all atrial arrhythmias, AF, and atrial tachycardia/flutter (AT/AFL). The secondary outcomes included total procedure time, ablation time, fluoroscopy time and procedure-related complications. Estimated risk ratios (RRs) and 95% confidence intervals (CIs) were evaluated.

RESULTS

Nine RCTs with a total of 1,243 non-paroxysmal AF patients were included in our analysis. There were no significant differences in all atrial arrhythmias recurrence (RR: 0.86, 95% CI: 0.66-1.11, p = 0.24, I2 = 49%) and AF recurrence (RR: 0.74, 95% CI: 0.51-1.08, p = 0.12, I2 = 62%) between stand-alone PVI group and PVI plus PWI group. Adjunctive PWI increased the AT/AFL recurrence rate (RR: 1.62 95% CI: 1.08-2.42, p = 0.02, I2 = 0%). In the subgroup analysis, PWI using cryoballoon ablation was associated with a significantly lower recurrence rate of all atrial arrhythmias (p = 0.01) and AF (p = 0.02) recurrence and similar recurrence rate of AT/AFL (p = 0.15). Additional PWI was associated with an increased AT/AFL recurrence (p = 0.03) in patients with left atrial diameter (LAD) <44 mm. Adjunctive PWI needed longer ablation time, fluoroscopy time, and total procedure time. The incidence of procedural adverse events was low and similar between both groups.

CONCLUSION

Adjunctive PWI beyond PVI did not improve the freedom from all atrial arrhythmias and AF with an increased recurrence rate of AT/AFL in non-paroxysmal AF patients. The ablation energy and LAD might affect the clinical outcome of PWI. However, larger more RCTs were needed to verify our findings.

Pulsed Field Ablation for Atrial Fibrillation: Mechanisms, Advantages, and Limitations

Pulsed field ablation with irreversible electroporation for the treatment of atrial fibrillation involves tissue-specific and non-thermal energy-induced cell necrosis, which helps avoid complications, such as pulmonary vein stenosis, atrial collateral tissue damage, and extensive atrial structural damage, often encountered with traditional thermal ablation. In existing clinical trials, pulsed field ablation has shown excellent effects on pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation. Pulsed field ablation is easy, simple, and quick and can reduce iatrogenic injury. Therefore, the application of pulsed field ablation technology in the treatment of atrial fibrillation has a promising future. Notably, the adjustment of parameters in pulsed field ablation with different ablation catheter systems can strongly affect the area and depth of the necrotic myocardium, which greatly affects the likelihood of atrial fibrillation recurrence and incidence of adverse complications after ablation. In this paper, we review the mechanisms, advantages, and limitations of pulsed field ablation based on the results of a series of previous studies and provide ideas and directions for future research.

Atrial fibrillation ablation during robotic mitral valve surgery: a systematic review and meta-analysis

Background

Atrial fibrillation (AF) is the most common arrhythmia, and is also associated with mitral valve disease. Although the benefits of robotic mitral valve surgery are well documented, literature combining robotic mitral valve surgery with AF surgery remains sparse. The aim of this systematic review and meta-analysis is to evaluate the evidence assessing the efficacy and safety of AF ablation during robotic mitral valve surgery.

Methods

Five electronic databases were searched from inception to April 2023. All studies reporting the primary outcome, freedom from AF, for patients with a history of AF undergoing robotic mitral valve surgery and AF ablation were identified. Studies which included mixed cohorts, or patients who did not undergo robotic mitral valve surgery were excluded. Relevant data were extracted and a meta-analysis of proportions was conducted using a random-effects model.

Results

Five studies were included with a total of 241 patients. Cohort sizes ranged from 11 to 94 patients. The aggregate mean age was 58.5 years and patients had persistent AF (71.1%). All five studies utilised the da Vinci® Surgical System, and performed variable lesion sets. The freedom from AF was 88.1% at a weighted mean follow-up of 6.9 months. There were two mortalities (0.8%), two patients required conversion to sternotomy (1.4%) and eight required a permanent pacemaker (3.7%).

Conclusions

AF ablation with robotic mitral valve surgery can be performed with adequate short-term efficacy and safety profile. Current evidence on AF ablation and robotic mitral valve surgery is limited to low-quality retrospective data with inherent selection bias. Further large-scale prospective data is required to verify these results.

Comparison of clinical outcomes of Ibutilide-guided cardioversion and direct current synchronized cardioversion after radiofrequency ablation of persistent atrial fibrillation

Backgroup

Ibutilide has already been used for cardioversion of persistent atrial fibrillation (PsAF) after radiofrequency catheter ablation (RFCA). The purpose of this study was to determine the effect of Ibutilide-guided cardioversion on clinical outcomes after individualized ablation of PsAF.

Methods

From October 2020 to September 2021, consecutive patients with PsAF accepted for RFCA were prospectively enrolled. After individualized ablation including pulmonary vein isolation plus left atrial roof line ablation and personalized linear ablation based on left atrial low-voltage zones, patients were divided into the spontaneous conversion (SCV) group, direct current synchronized cardioversion (DCC) group and Ibutilide group according to different cardioversion types during ablation. The rates of freedom from atrial tachyarrhythmia (ATT) among the three groups were evaluated after follow-up.

Results

In this study, 110 patients were enrolled, including 12 patients with SCV, 50 patients receiving DCC and 48 patients receiving Ibutilide cardioversion after individualized ablation. Among the three groups, the SCV group had shorter AF duration {12 months [interquartile range (IQR) 12-16], P = 0.042} and smaller left atrial diameter (LAD) [35 mm (IQR: 33-42), P = 0.023]. A 12-month freedom from ATT rate was 83.3% in SCV group, 69.4% in DCC group, and 79.2% in Ibutilide group, respectively (Log-rank, P = 0.745). During the follow-up [17 months (IQR: 15-19)], the rate of freedom from ATT of SCV group (83.3%), and Ibutilide group (72.9%) were both higher than that of DCC group (53.1%, P = 0.042). Moreover, Kaplan-Meier analysis showed a significantly higher sinus rhythm (SR) maintenance in Ibutilide group than in DCC group (Log-rank, P = 0.041). After adjusting for risk factors of AF recurrence, the hazard ratio for AF recurrence of the DCC group with reference to the Ibutilide group was 4.10 [95% confidence interval (CI) (1.87-8.98), P < 0.001]. Furthermore, subgroup analysis showed that freedom from ATT rate in effective Ibutilide subgroup was significantly higher than noneffective Ibutilide subgroup (Log-rank, P < 0.001).

Conclusion

For the treatment of the patients with PsAF, Ibutilide-guided cardioversion after individualized RFCA may be benefit for maintenance of SR compared to conventional DCC, especially for the patients who are effective for administration of Ibutilide.

Ongoing substrate-driven atrial fibrillation "boxed" in the left atrial posterior wall with ablation: a case report

Patients undergoing valve surgery for rheumatic heart disease are expected to develop significant atrial arrhythmogenic substrates outside of the pulmonary veins, which sometimes require complex ablation techniques for the treatment of symptomatic arrhythmias. We describe, herein, the case of a 76-year-old male undergoing endocardial ablation for the treatment of symptomatic persistent atrial fibrillation which developed after aortic and mitral valve replacement with a simultaneous tricuspid ring annuloplasty. Following pulmonary vein isolation, the patient's atrial fibrillation was converted into cavotricuspid isthmus-dependent atrial flutter. After a successful cavotricuspid isthmus ablation, the arrhythmia reverted back to a left atrial tachyarrhythmia originating from the posterior wall. A linear left atrial lesion led to the electrical isolation of a large area, which included the posterior wall, as well as the containment of the ongoing fibrillatory activity, while sinus rhythm was restored in the rest of the atria. In conclusion, successful left atrial posterior wall isolation can be achieved in the setting of severe scarring due to previous atriotomy by creating a linear lesion on the atrial roof, in conjunction with pulmonary vein isolation, sparing the patient from requiring bottom-line ablation, and avoiding possible esophageal injury. Such compartmentalization of the left atrium may effectively contain local fibrillatory activity, while allowing for the restoration of sinus rhythm.

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.

Comparing Left Atrial Low Voltage Areas in Sinus Rhythm and Atrial Fibrillation Using Novel Automated Voltage Analysis: A Pilot Study

BACKGROUND

Low voltage areas (LVAs) have been proposed as surrogate markers for left atrial (LA) scar. Correlation between voltages in sinus rhythm (SR) and atrial fibrillation (AF) have previously been measured via point-by-point analysis. We sought to compare LA voltage composition measured in SR to AF, utilizing a high-density automated voltage histogram analysis (VHA) tool in those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF).

METHODS

We retrospectively analyzed patients with PeAF undergoing de novo PVI. Maps required ≥ 1,000 voltage points in each rhythm and had a standardized procedure (mapped in AF then remapped in SR post-PVI). We created six anatomical segments (AS) from each map: anterior, posterior, roof, floor, septal and lateral AS. These were analyzed by VHA, categorizing atrial LVAs into 10 voltage aliquots 0 - 0.5 mV. Data were analyzed using SPSS v.26.

RESULTS

We acquired 58,342 voltage points (n = 10 patients, mean age: 67 ± 13 years, three females). LVA burdens of ≤ 0.2 mV, designated as "severe LVAs", were comparable between most AS (except on the posterior wall) with good correlation. Mapped voltages between the ranges of 0.21 and 0.5 mV were labeled as "diseased LA tissue", and these were found significantly more in AF than SR. Significant differences were seen on the roof, anterior, posterior, and lateral AS.

CONCLUSIONS

Diseased LA tissue (0.21 - 0.5 mV) burden is significantly higher in AF than SR, mainly in the anterior, roof, lateral, and posterior wall. LA "severe LVA" (≤ 0.2 mV) burden is comparable in both rhythms, except with respect to the posterior wall. Our findings suggest that mapping rhythm has less effect on the LA with voltages < 0.2 mV than 0.2 - 0.5 mV across all anatomical regions, excluding the posterior wall.

Mid term freedom from atrial fibrillation following hybrid ablation, a systematic review and meta analysis

INTRODUCTION

Atrial Fibrillation (AF) is a common tachyarrhythmia affecting 33 million people worldwide. Hybrid AF ablation utilises a surgical (epicardial) ablation followed by an endocardial catheter-based ablation. The aim of this systematic review and meta-analysis is to summarize the literature reporting mid-term freedom from AF following hybrid ablation.

METHODS

An electronic search of databases was performed to identify all relevant studies providing mid-term (2 year) outcomes following hybrid ablation for AF. The primary study outcome was to assess the mid-term freedom from AF following hybrid ablation, utilising the metaprop function on Stata® (Version 17.0, StataCorp, Texas, USA). Subgroup analysis was performed to assess the impact of various operative characteristics on mid-term freedom from AF. The secondary outcomes assessed mortality and procedural complication rate.

RESULTS

The search strategy identified 16 studies qualifying for inclusion in this meta-analysis, with 1242 patients in total. The majority of papers were retrospective cohort studies (15) and one study was a randomized control trial (RCT). The mean follow up was 31.5 ± 8.4 months. Following hybrid ablation, the overall mid-term freedom from AF was 74.6% and 65.4% for patients off antiarrhythmic drugs (AAD). Actuarial freedom from AF was 78.2%, 74.2% and 73.6% at 1, 2 and 3 years respectively. No significant differences in mid-term freedom from AF based epicardial lesion set (box vs pulmonary vein isolation) or Left atrial appendage/Ganglionated Plexus/Ligament of Marshall ablation or staged vs concomitant procedures. There were 12 deaths overall following the hybrid procedure with a pooled complication rate of 5.53%.

CONCLUSION

Hybrid AF ablation offers promising mid-term freedom from AF reported at a mean follow-up of 31.5 months. The overall complication rate remains low. Further analysis of high-quality studies with randomized data and long-term follow up will help verify these results.

Hybrid Ablation of Atrial Fibrillation: A Contemporary Overview

Electrical isolation of pulmonary veins (PVI) is the cornerstone of invasive treatment of atrial fibrillation (AF). However, arrhythmia-free survival of a PVI only approach is suboptimal in patients with persistent and long-term persistent AF. Hybrid AF ablation has been developed with the aim of combining the advantages of a thoracoscopic surgical ablation (direct visualization of anatomical structures to be spared and the possibility to perform epicardial lesions) and endocardial ablation (possibility to check line block, confirm PVI, and possibility to perform cavotricuspid isthmus ablation). Patient selection is of utmost importance. In persistent and long-term persistent AF, hybrid AF ablation demonstrated promising results in terms of AF free survival. It has been associated with a relatively low complication rate if performed in centers with expertise in hybrid procedures and experience with both surgical and endocardial ablation. Different techniques have been described, with different approaches and lesion sets. The aim of this review is to provide a state-of-the-art overview of hybrid AF ablation.

The Convergent Ablation and AtriClip Exclusion of the Left Atrial Appendage in Long-Standing Persistent Atrial Fibrillation

We here present a case of a 54-year-old man with longstanding persistent atrial fibrillation refractory to direct current electrical cardioversion who underwent a concurrent convergent ablation and Atriclip exclusion of left atrial appendage. His preoperative echocardiography revealed dilated 5.8 cm left atrium with a normal left ventricular ejection fraction of 50%. Transmural isolation of pulmonary veins was performed through a subxiphoid approach, and 3 left-sided video-assisted thoracoscopic surgery ports were utilised to occlude the base of the left atrium appendage with the Atriclip device. A peri-operative transoesophageal echocardiogram confirmed left atrium appendage base occlusion, and the patient was in sinus rhythm after having a single 200 kJ direct current cardioversion shock. The postoperative period was uneventful, and the patient was discharged with preprocedural anticoagulant after 24 hours of the procedure and advised to come for follow up after 3 months.

A Chronicle of Hybrid Atrial Fibrillation Ablation Therapy: From Cox Maze to Convergent

The burden of AF is increasing in prevalence and healthcare resource usage in the UK and worldwide. It can result in impaired quality of life for affected patients, as well as increased risk of stroke, heart failure and mortality. A holistic, integrated approach to AF management is recommended, which may include a focus on reducing risk factors and on medical management with anticoagulation and anti-arrhythmic drugs. There are also various ablation strategies that may be considered when anti-arrhythmic drugs fail to alleviate symptoms and reduce AF burden. These ablation techniques range from standalone percutaneous endocardial catheter ablation to open surgical ablation procedures concomitant with cardiac surgery. More recently, hybrid ablation that combines aspects of both surgical and electrophysiologically targeted ablation has been described. This article reviews the evolution of ablation strategies, beginning with the origin of the Cox maze IV procedure and continuing to the recent hybrid convergent approach, and provides a summary of the associated outcomes.

Sinus Node Dysfunction after Successful Atrial Flutter Ablation during Follow-Up: Clinical Characteristics and Predictors

Identification of sinus node dysfunction (SND) before termination of persistent AFL by catheter ablation (CA) is challenging. This study aimed to investigate the characteristics and predictors of acute and delayed SND after AFL ablation. We retrospectively enrolled 221 patients undergoing CA of persistent AFL in a tertiary referral center. Patients with SND who required a temporary pacemaker (TPM) after termination of AFL or a permanent pacemaker (PPM) during follow-up were identified. Acute SND requiring a TPM was found in 14 of 221 (6.3%) patients following successful termination of AFL. A total of 10 of the 14 patients (71.4%) recovered from acute SND. An additional 11 (5%) patients presenting with delayed SND required a PPM during follow-up, including 4 patients recovering from acute SND. Of these, 9 of these 11 patients (81.8%) underwent PPM implantation within 1 year after the ablation. In multivariable analysis, female gender and a history of hypothyroidism were associated with the requirement for a TPM following termination of persistent AFL, while older age and a history of hypothyroidism predicted PPM implantation. This study concluded that the majority of patients with acute SND still require a PPM implantation despite the initial improvement. Therefore, it is reasonable to monitor the patients closely for at least one year after AFL ablation.

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.

The wall of unintended consequences: is the main benefit of posterior LA wall isolation simply more durable pulmonary vein isolation?

Medicine is rife with therapies originally developed for a specific purpose, yet after some time, the true benefit is determined to lie elsewhere - examples of the "law of unintended consequences". This article is protected by copyright. All rights reserved.