Marshall bundle elimination, Pulmonary vein isolation, and Line completion for ANatomical ablation of persistent atrial fibrillation (Marshall-PLAN): Prospective, single-center study

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.

A proposed index of myocardial staining for vein of Marshall ethanol infusion: an Italian single-center experience

BACKGROUND

Mitral isthmus (MI) conduction block is a fundamental step in anatomical approach treatment for persistent atrial fibrillation (PeAF). However, MI block is hardly achievable with endocardial ablation only. Retrograde ethanol infusion (EI) into the vein of Marshall (VOM) facilitates MI block. Fluorographic myocardial staining (MS) during VOM-EI could be helpful in predicting procedural alcoholization outcome even if its role is qualitatively assessed in the routine. The aim was to quantitatively assess MS during VOM-EI and to evaluate its association with MI block achievement.

METHODS

Consecutive patients undergoing catheter ablation for PeAF at Fondazione Toscana Gabriele Monasterio (Pisa, Italy) from February 2022 to May 2023 were considered. Patients with identifiable VOM were included. A proposed index of MS (MSI) was retrospectively calculated in each included patient. Correlation of MSI with low-voltage zones (LVZ) extension after VOM-EI and its association with MI block achievement were assessed.

RESULTS

In total, 42 patients out of 49 (85.8%) had an identifiable VOM. MI block was successfully achieved in 35 patients out of 42 (83.3%). MSI was significantly associated with the occurrence of MI block (OR 1.24 (1.03-1.48); p = 0.022). A higher MSI resulted in reduced ablation time (p = 0.014) and reduced radiofrequency applications (p = 0.002) to obtain MI block. MSI was also associated with MI block obtained by endocardial ablation only (OR 1.07 (1.02-1.13); p = 0.002). MSI was highly correlated with newly formed LVZ extension (r = 0.776; p = 0.001).

CONCLUSIONS

In our study cohort, optimal MSI predicts MI block and facilitates its achievement with endocardial ablation only.

The use of Intracardiac Echocardiography in Catheter Ablation of Atrial Fibrillation

PURPOSE OF THE REVIEW

Intracardiac echocardiography (ICE) provides real-time, fluoroless imaging of cardiac structures, allowing optimal catheter positioning and energy delivery during ablation procedures. This review summarizes the use of ICE in catheter ablation of atrial fibrillation (AF).

RECENT FINDINGS

Growing evidence suggests that the use of ICE improves procedural safety and facilitates radiofrequency and cryoballoon AF ablation. ICE-guided catheter ablation is associated with reduced procedural duration and fluoroscopy use. Recent studies have examined the role of ICE in guiding novel ablation techniques, such as pulsed field ablation. Finally, the use of ICE allows for early detection and timely management of potentially serious procedural complications. Intracardiac echocardiography offers significant advantages during AF ablation procedures and its use should be encouraged to improve procedural safety and efficacy.

Impact of Posterior Wall Isolation During AF Ablation on the Incidence of Left Atrial Flutter

BACKGROUND

Linear and complex electrogram ablation (LCEA) beyond pulmonary vein isolation (PVI) is associated with an increase in left atrial macro-re-entrant tachycardias (LAMTs). Posterior wall isolation (PWI) is increasingly performed to improve AF ablation outcomes. However, the impact of PWI on the incidence of LAMT is unknown.

OBJECTIVES

The purpose of this study was to establish the incidence of LAMT following PVI alone vs PVI + PWI vs PVI + PWI + LCEA.

METHODS

Consecutive patients undergoing catheter ablation for AF or LAMT post-AF ablation between 2008 and 2022 from 4 electrophysiology centers were reviewed with a minimum follow-up of 12 months.

RESULTS

In total, 5,619 (4,419 index, 1,100 redo) AF ablation procedures were performed in 4,783 patients (mean age 60.9 ± 10.6 years, 70.7% men). Over a mean follow-up of 6.4 ± 3.8 years, 246 procedures for LAMT were performed in 214 patients at a mean of 2.6 ± 0.6 years post-AF ablation. Perimitral (52.8% of patients), roof-dependent (27.1%), PV gap-related (17.3%), and anterior circuits (8.9%) were most common, with 16.4% demonstrating multiple circuits. The incidence of LAMT was significantly higher following PVI + PWI (6.2%) vs PVI alone (3.0%; P < 0.0001) and following PVI + PWI + LCEA vs PVI + PWI (12.5%; P = 0.019). Conduction gaps in previous ablation lines were responsible for LAMT in 28.4% post-PVI alone, 35.3% post-PVI + PWI (P = 0.386), and 81.8% post-PVI + PWI + LCEA (P < 0.005).

CONCLUSIONS

The incidence of LAMT following PVI + PWI is higher than with PVI alone but significantly lower than with more extensive atrial substrate modification. Given a low frequency of LAMT following PWI, empiric mitral isthmus ablation is not justified and may be proarrhythmic.

Vein of Marshall chemical ablation decreases atrial fibrillation drivers detected by CARTOFINDER

INTRODUCTION

This study sought to elucidate the impact of vein of Marshall (VOM) chemical ablation on atrial fibrillation (AF) drivers by investigating the changes in CARTOFINDER mappings before and after VOM chemical ablation in patients with persistent AF.

METHODS

This study included 23 consecutive patients undergoing catheter ablation for long-persistent AF (>18 months). VOM chemical ablation was performed following pulmonary vein isolation. CARTOFINDER and AF cycle length (AFCL) maps were created in the left atrium (LA) before and after VOM chemical ablation. The LA was divided into 8 segments, and the number of focal activation points with 6 or more repetitions was counted in each segment.

RESULTS

The number of focal activation points was largest in the LA appendage (LAA). After VOM chemical ablation, the number of focal activation points in the LA decreased significantly (37 [interquartile range, IQR: 19-55] vs. 15 [IQR: 7-21], p < .001), and median AFCL was significantly prolonged (159 [147-168] vs. 164 [150-173] ms, p < .001). In the assessment of each segment, significant decreases in focal activation points were observed in the inferior, lateral, and anterior segments and LAA. Among the focal activation points disappearing after chemical ablation, the number in the non-ethanol-affected area was significantly larger than that in the affected area (13 [8-25] vs. 4 [1-10], p < .001).

CONCLUSIONS

VOM chemical ablation decreases AF drivers detected by CARTOFINDER. Mechanisms other than direct myocardial damage are considered to contribute the attenuation of AF drivers.

Protocol modifications reduce risk of delayed pericardial effusions after vein of Marshall ethanol infusion: follow-up from the Maine experience

BACKGROUND

While ethanol infusion into the vein of Marshall (VOM) as an adjunct to atrial fibrillation ablation has shown promise, adoption has been limited by the technical expertise required, unclear antiarrhythmic mechanism, and complication risk. Delayed pericardial effusions have been associated with ethanol infusion into the VOM in prior studies. Very little is known about how the procedural approach itself can impact the risk of delayed effusions. We sought to understand the incidence and influence of procedural technique on complications including delayed pericardial effusions from VOM ethanol infusion at a large single medical center.

METHODS

A total of 275 atrial ablation cases wherein VOM ethanol infusion was attempted were identified from the time of the program's inception in 2019 at Maine Medical Center (Portland, ME) until October of 2023. Cases were classified into phase I cases (early experience) and phase II cases (later experience) based upon temporal programmatic changes in the ethanol dose and infusion rate as well as the use of routine VOM venography. Procedural details and complications were adjudicated from the medical record.

RESULTS

The overall VOM ethanol infusion success was 91.4%. Nine complications (3.3%) occurred in eight patients (2.9% of patients). These were more frequent in phase I (5.8%) compared to phase II (1.3%, p = 0.047). This difference was driven by a difference in delayed presentations of tamponade, which occurred in four patients in phase I (3.3%) and in no patients in phase II (0%, p = 0.037). Twelve-month estimated atrial arrhythmia freedom did not differ between groups (73.8% phase I vs 70.4% phase II, p = 0.24).

CONCLUSION

In our single-center experience, adjustments to the procedural approach with lower ethanol infusion rate and dosage, combined with utilizing selective VOM venography, associated with a lowering of complication rates and in particular, delayed pericardial tamponade.

Impact of Ethanol Infusion to the Vein of Marshall in Atrial Fibrillation and Atrial Tachycardia

The ligament of Marshall is an epicardial structure characterized by its composition of fat, fibrous tissue, blood vessels, muscle bundles, nerve fibers, and ganglia. Its intricate network forms muscular connections with the coronary sinus and left atrium, alongside adjacent autonomic nerves and ganglion cells. This complexity plays a pivotal role in initiating focal electrical activities and sustaining micro- and macro-reentrant circuits, thereby contributing to the onset of atrial fibrillation and atrial tachycardia. However, endocardial ablation in this area may encounter challenges due to anatomical variations and insulation by fibrofatty tissue. Combining ethanol infusion into the vein of Marshall with radiofrequency ablation presents a promising strategy for effectively and safely eliminating this arrhythmogenic structure and terminating associated tachycardias.

In Silico TRials guide optimal stratification of ATrIal FIbrillation patients to Catheter Ablation and pharmacological medicaTION: the i-STRATIFICATION study

AIMS

Patients with persistent atrial fibrillation (AF) experience 50% recurrence despite pulmonary vein isolation (PVI), and no consensus is established for secondary treatments. The aim of our i-STRATIFICATION study is to provide evidence for stratifying patients with AF recurrence after PVI to optimal pharmacological and ablation therapies, through in silico trials.

METHODS AND RESULTS

A cohort of 800 virtual patients, with variability in atrial anatomy, electrophysiology, and tissue structure (low-voltage areas, LVAs), was developed and validated against clinical data from ionic currents to electrocardiogram. Virtual patients presenting AF post-PVI underwent 12 secondary treatments. Sustained AF developed in 522 virtual patients after PVI. Second ablation procedures involving left atrial ablation alone showed 55% efficacy, only succeeding in the small right atria (<60 mL). When additional cavo-tricuspid isthmus ablation was considered, Marshall-PLAN sufficed (66% efficacy) for the small left atria (<90 mL). For the bigger left atria, a more aggressive ablation approach was required, such as anterior mitral line (75% efficacy) or posterior wall isolation plus mitral isthmus ablation (77% efficacy). Virtual patients with LVAs greatly benefited from LVA ablation in the left and right atria (100% efficacy). Conversely, in the absence of LVAs, synergistic ablation and pharmacotherapy could terminate AF. In the absence of ablation, the patient's ionic current substrate modulated the response to antiarrhythmic drugs, being the inward currents critical for optimal stratification to amiodarone or vernakalant.

CONCLUSION

In silico trials identify optimal strategies for AF treatment based on virtual patient characteristics, evidencing the power of human modelling and simulation as a clinical assisting tool.

Chinese guidelines for the diagnosis and management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of the guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice timely and fully, the Chinese Society of Cardiology of Chinese Medical Association and the Heart Rhythm Committee of Chinese Society of Biomedical Engineering jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2‑VASc‑60 stroke risk score based on the characteristics of the Asian AF population. The guidelines also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Pulsed Field Energy in Atrial Fibrillation Ablation: From Physical Principles to Clinical Applications

Atrial fibrillation, representing the most prevalent sustained cardiac arrhythmia, significantly impacts stroke risk and cardiovascular mortality. Historically managed with antiarrhythmic drugs with limited efficacy, and more recently, catheter ablation, the interventional approach field is still evolving with technological advances. This review highlights pulsed field ablation (PFA), a revolutionary technique gaining prominence in interventional electrophysiology because of its efficacy and safety. PFA employs non-thermal electric fields to create irreversible electroporation, disrupting cell membranes selectively within myocardial tissue, thus preventing the non-selective damage associated with traditional thermal ablation methods like radiofrequency or cryoablation. Clinical studies have consistently shown PFA's ability to achieve pulmonary vein isolation-a cornerstone of AF treatment-rapidly and with minimal complications. Notably, PFA reduces procedure times and has shown a lower incidence of esophageal and phrenic nerve damage, two common concerns with thermal techniques. Emerging from oncological applications, the principles of electroporation provide a unique tissue-selective ablation method that minimizes collateral damage. This review synthesizes findings from foundational animal studies through to recent clinical trials, such as the MANIFEST-PF and ADVENT trials, demonstrating PFA's effectiveness and safety. Future perspectives point towards expanding indications and refinement of techniques that promise to improve AF management outcomes further. PFA represents a paradigm shift in AF ablation, offering a safer, faster, and equally effective alternative to conventional methods. This synthesis of its development and clinical application outlines its potential to become the new standard in AF treatment protocols.

Predictors of systolic function recovery after atrial fibrillation ablation in heart failure patients

INTRODUCTION AND OBJECTIVES

Atrial fibrillation (AF) and heart failure (HF) often coexist. AF catheter ablation improves left ventricular ejection fraction (LVEF), but its impact varies between patients. We aimed to identify predictors of LVEF improvement in HF patients with impaired LVEF undergoing AF ablation.

METHODS

We conducted a retrospective single-center study in HF patients with LVEF <50% undergoing AF catheter ablation between May 2016 and May 2022. The primary endpoint was the LVEF recovery rate ('responders'). Secondary endpoints were one-year safety and effectiveness. We also aimed to validate a prediction model for LVEF recovery.

RESULTS

The study included 100 patients (79% male, median age 60 years, 70% with probable tachycardia-induced cardiomyopathy [TIC], mean LVEF 37%, 29% with paroxysmal AF). After a median follow-up of 12 months after catheter ablation, LVEF improved significantly (36±10% vs. 53±10%, p<0.001), with an 82% responder rate. A suspected diagnosis of TIC (OR 4.916 [95% CI 1.166-20.732], p=0.030), shorter QRS duration (OR 0.969 [95% CI 0.945-0.994], p=0.015), and smaller left ventricle (OR 0.893 [95% CI 0.799-0.999], p=0.049) were independently associated with LVEF improvement. Freedom from any documented atrial arrhythmia was 86% (64% under antiarrhythmic drugs), and the rate of adverse events was 2%. The prediction model had a good discriminative performance (AUC 0.814 [95% CI 0.681-0.947]).

CONCLUSION

In AF patients with HF and impaired LVEF, suspected TIC, shorter QRS duration, and smaller LV diameter were associated with LVEF recovery following AF catheter ablation.

Vein of Marshall Ethanol Infusion for AF Ablation; A Review

The outcomes of persistent atrial fibrillation (AF) ablation are modest with various adjunctive strategies beyond pulmonary vein isolation (PVI) yielding largely disappointing results in randomised controlled trials. Linear ablation is a commonly employed adjunct strategy but is limited by difficulty in achieving durable bidirectional block, particularly at the mitral isthmus. Epicardial connections play a role in AF initiation and perpetuation. The ligament of Marshall has been implicated as a source of AF triggers and is known to harbour sympathetic and parasympathetic nerve fibres that contribute to AF perpetuation. Ethanol infusion into the Vein of Marshall, a remnant of the superior vena cava and key component of the ligament of Marshall, may eliminate these AF triggers and can facilitate the ease of obtaining durable mitral isthmus block. While early trials have demonstrated the potential of Vein of Marshall 'ethanolisation' to reduce arrhythmia recurrence after persistent AF ablation, further randomised trials are needed to fully determine the potential long-term outcome benefits afforded by this technique.

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.

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.

Efficiency and Durability of EIVOM on Acute Reconnection After Mitral Isthmus Bidirectional Block

BACKGROUND

Reconnection after mitral isthmus (MI) block with radiofrequency ablation is common.

OBJECTIVES

The aim of this study was to investigate the effects of ethanol infusion in the vein of Marshall (EIVOM) on acute reconnection after MI bidirectional block.

METHODS

Patients with persistent atrial fibrillation who were scheduled to receive radiofrequency ablation for the first time were randomly assigned to the radiofrequency catheter ablation (RFCA) group (n = 44) or the EIVOM group (n = 45). The RFCA group's strategy was bilateral pulmonary vein ablation and linear ablation; in the EIVOM group, EIVOM was performed first. The primary endpoint was acute reconnection 30 minutes after MI bidirectional block.

RESULTS

A total of 89 patients (average age 62.9 years; 57.3% male) were enrolled. The average duration for persistent atrial fibrillation was 2.3 years. Before observation, all patients in the EIVOM group achieved MI bidirectional block (45 of 45 [100%]), compared with 84.1% (37 of 44) in the RFCA group. After the observation, 3 cases of MI reconnection occurred in the EIVOM group and 13 cases in the RFCA group (6.7% vs 35.1%; P < 0.05). After additional ablation, the final MI block rates in the EIVOM and RFCA groups were 97.8% (44 of 45) and 72.7% (32 of 44), respectively. During a 1-year follow-up, 8 of 45 patients who underwent EIVOM had recurrent atrial fibrillation, compared with 14 of 44 in the RFCA group (17.8% vs 31.8%; P < 0.01).

CONCLUSIONS

EIVOM can reduce acute reconnection after MI bidirectional block and significantly increase first-pass MI block.

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 .

Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice in a timely and comprehensive manner, the Chinese Society of Cardiology of the Chinese Medical Association and the Heart Rhythm Committee of the Chinese Society of Biomedical Engineering have jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines have comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2-VASc-60 stroke risk score based on the characteristics of AF in the Asian population. The guidelines have also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Use of intracardiac echocardiography in vein of Marshall ethanol infusion for ablation of persistent atrial fibrillation

BACKGROUND

Few methods have been reported to demonstrate real-time effects during vein of Marshall (VOM) ethanol infusion in persistent atrial fibrillation (PeAF).

OBJECTIVE

This study was to evaluate the impact of left atrial (LA) monitoring using intracardiac echocardiography (ICE) during VOM ethanol infusion.

METHODS

Seventy-four consecutive patients with PeAF who underwent VOM ethanol infusion followed by radiofrequency (RF) ablation were included. Patients with findings on ICE consistent with echogenic streaming in the LA and with increased myocardial local echogenicity along the VOM area were placed into one group (group A) and those without into the other group (group B). Outcomes between the 2 groups were compared.

RESULTS

Forty-six patients (62%) were placed into group A. A new ethanol-induced low-voltage area in group A was larger than that in group B (8.5 cm2 [5.5-10.2 cm2] and 4.0 cm2 (2.4-6.3 cm2]; P < .001). The RF ablation time required to achieve MI block was reduced in group A patients (263.0 seconds [196.0-351.0 seconds] vs 417.0 seconds [315.0-709.5 seconds] in group B patients; P < .001). MI block was achieved in 46 patients (100%) via an endocardial approach in group A and 27 patients (96.4%) in group B (extra coronary sinus ablation in 4 patients). One patient developed clinically significant pericardial effusions and required pericardiocentesis in group B.

CONCLUSION

Presence of increased myocardial local echogenicity at the ridge and consistent echogenic streaming in the LA detected by ICE-based imaging during VOM ethanol infusion suggests increased ablated tissue in that region and lower RF ablation time during ablation for PeAF.

The effect of an initial catheter ablation with an adjunctive ethanol infusion into the vein of Marshall on persistent atrial fibrillation

INTRODUCTION

Some previous studies have reported that a first-step ethanol infusion into the vein of Marshall (EIVOM) with touch-up radiofrequency (RF) ablation can facilitate mitral isthmus (MI) block and improves the ablation outcomes in persistent atrial fibrillation (PeAF) patients. However, the effect of an initial RF ablation with an adjunctive EIVOM has not been fully investigated.

METHODS

This study enrolled 233 PeAF patients undergoing pulmonary vein isolation and linear ablation including an MI, roof line, and cavotricuspid isthmus ablation. An EIVOM was performed when endocardial ablation with or without coronary sinus ablation failed to create MI block.

RESULTS

Bidirectional MI block was achieved in 224 patients (96.1%). Among them, MI block was obtained by only RF ablation in 174/224 patients (77.7%) (RF group) and an adjunctive EIVOM was needed in 50/224 (22.3%) (EIVOM group). During the follow-up, 113 (64.9%) RF group patients were free from AF/atrial tachycardia compared to 41 (82.0%) EIVOM group patients (log-rank p = .045). In a multivariate Cox regression analysis, an adjunctive EIVOM was associated with a lower recurrence rate (hazard ratio = 0.39, 95% confidence interval = 0.17-0.78, p = .006).

CONCLUSION

An initial RF ablation with an adjunctive EIVOM strategy improved MI ablation's acute success rate and was associated with better clinical outcomes.

Subjective identification and ablation of drivers improves rhythm control in patients with persistent atrial fibrillation. The CHAOS-AF study

INTRODUCTION AND OBJECTIVES

The optimal approach for persistent atrial fibrillation (AF) ablation remains unknown. In patients with persistent AF, we compared an ablation strategy based on pulmonary vein isolation (PVI) plus ablation of drivers (PVI+D), with a conventional PVI-only approach performed in a 1:1 propensity score-matched cohort.

METHODS

Drivers were subjectively identified using conventional high-density mapping catheters (IntellaMap ORION, PentaRay NAV or Advisor HD Grid), without dedicated software, as fractionated continuous or quasicontinuous electrograms on 1 to 2 adjacent bipoles, which were ablated first; and as sites with spatiotemporal dispersion (the entire cycle length comprised within the mapping catheter) plus noncontinuous fractionation, which were only targeted in patients without fractionated continuous electrograms, or without AF conversion after ablation of fractionated continuous electrograms. Ablation included PVI plus focal or linear ablation targeting drivers.

RESULTS

A total of 50 patients were included in each group (61±10 years, 25% women). Fractionated continuous electrograms were found and ablated in 21 patients from the PVI+D group (42%), leading to AF conversion in 7 patients. In the remaining 43 patients, 143 sites with spatiotemporal dispersion plus noncontinuous fractionation were targeted. Globally, AF conversion was achieved in 21 patients (42%). The PVI+D group showed lower atrial arrhythmia recurrences at 1 year of follow-up (30.6% vs 48%; P=.048) and at the last follow-up (46% vs 72%; P=.013), and less progression to permanent AF (10% vs 40%; P=.001).

CONCLUSIONS

Subjective identification and ablation of drivers, added to PVI, increased 1-year freedom from atrial arrhythmia and decreased long-term recurrences and progression to permanent AF.

Clinical effect of vein of Marshall ethanol infusion on mitral isthmus ablation

Purpose

This study aimed to investigate the effect of Marshall ethanol infusion (VOM-Et) in the vein on mitral isthmus (MI) ablation.

Methods

Patients with persistent atrial fibrillation (AF) were grouped into vein of VOM-Et combined with radiofrequency (RF) ablation (VOM-Et-RF) and RF groups. The primary outcome was MI block immediate block rate after surgery. Stratified analysis was also performed for factors affecting the outcome measures.

Results

A total of 118 consecutive patients underwent AF ablation at Taizhou Hospital of Zhejiang Province from January 2018 to December 2021. Successful bidirectional perimitral block was achieved in 96% of patients in VOM-Et-RF (69 of 72) and in 76% of patients in the RF group (35 of 46) (P < 0.01). In the subgroup analysis, male sex, elder than 60 years, Left atrial diameter <55 mm, and AF duration <3 years were associated with the benefits of VOM-Et in AF Patients.

Conclusion

The vein of Marshall ethanol infusion for catheter ablation can improve the MI block rate. Male sex, elder age, smaller Left atrial diameter and shorter AF duration may have significant benefits for VOM-Et.

Acute mitral isthmus block during catheter ablation with vein of Marshall ethanol infusion: Angiographic considerations

BACKGROUND

Achieving bidirectional mitral isthmus block is still challenging. Conventional ablation methods involve radiofrequency applications on the endocardial aspect of the lateral mitral isthmus, and often epicardial applications inside the coronary sinus.

AIM

To evaluate the impact of the systematic use of ethanol infusion in the vein of Marshall on the achievement of acute mitral isthmus block of additional epicardial component lesion.

METHODS

We evaluated patients referred to two centres for long-standing persistent atrial fibrillation ablation or recurrent peri-mitral flutter. All patients had pulmonary vein isolation and mitral isthmus line using ethanol infusion in the vein of Marshall for the first procedure and additional radiofrequency ablation lesion if necessary. For redo procedures, additional ablations (atrial lines and complex fractionated atrial electrogram ablations, if needed) were also performed.

RESULTS

We included 149 patients, and ethanol infusion in the vein of Marshall was not performed in 27 patients (18%). Among 122 patients, 115 had long-standing persistent atrial fibrillation (94.2%) and seven had peri-mitral flutter (5.8%). The mean duration of continuous atrial fibrillation was 53 months before ablation. Acute bidirectional mitral isthmus block was obtained in 115 (94.2%) of the 122 patients who received ethanol infusion in the vein of Marshall (77% when considering the total population). The mean radiofrequency delivery time to obtain mitral isthmus block was 2.6minutes for the endocardial mitral isthmus radiofrequency ablation and 2.6minutes for the epicardial mitral isthmus radiofrequency ablation. Failure to obtain mitral isthmus block was associated with increased mitral isthmus length and left atrial dilation. No major complications related to ethanol infusion in the vein of Marshall were observed.

CONCLUSION

Ethanol infusion in the vein of Marshall, when feasible (82%), was a safe approach to obtaining a high success rate (94%) of acute bidirectional endocardial and epicardial mitral isthmus block.

Ablation of persistent atrial fibrillation based on atrial electrogram duration map: methodology and clinical outcomes from the AEDUM pilot study

BACKGROUND

Catheter ablation of persistent atrial fibrillation (PsAF) represents a challenge for the electrophysiologist and there are still divergences regarding the best ablative approach to adopt. Create a new map of the duration of atrial bipolar electrograms (Atrial Electrogram DUration Map, AEDUM) to recognize a functional substrate during sinus rhythm and guide a patient-tailored ablative strategy for PsAF.

METHODS

Forty PsAF subjects were assigned in a 1:1 ratio to either for PVI alone (Group B1) or PVI+AEDUM areas ablation (Group B2). A cohort of 15 patients without AF history undergoing left-sided accessory pathway ablation was used as a control group (Group A). In all patients, voltage and AEDUM maps were created during sinus rhythm. The minimum follow-up was 12 months, with rhythm monitoring via 48-h ECG Holter or by implantable cardiac device.

RESULTS

Electrogram (EGM) duration was higher in Group B than in Group A (49±16.2ms vs 34.2±3.8ms; p-value<0.001). In Group B the mean cumulative AEDUM area was 21.8±8.2cm2; no difference between the two subgroups was observed (22.3±9.1cm2 vs 21.2±7.2cm2; p-value=0.45). The overall bipolar voltage recorded inside the AEDUM areas was lower than in the remaining atrial areas [median: 1.30mV (IQR: 0.71-2.38mV) vs 1.54mV (IQR: 0.79-2.97mV); p-value: <0.001)]. Low voltage areas (<0.5mV) were recorded in three (7.5%) patients in Group B. During the follow-up [median 511 days (376-845days)] patients who underwent PVI-only experienced more AF recurrence than those receiving a tailored approach (65% vs 35%; p-value= 0.04).

CONCLUSIONS

All PsAF patients exhibited AEDUM areas. An ablation approach targeting these areas resulted in a more effective strategy compared with PVI only.

Persistent atrial fibrillation without the evidence of low-voltage areas: a prospective randomized trial

BACKGROUND

An effective therapy of persistent atrial fibrillation beyond pulmonary vein isolation remains unsatisfactory. Targeting endocardial low-voltage areas represents an approach of substrate modification. This prospective, randomized study investigated the efficacy of ablation of low-voltage areas versus PVI and additional linear ablations in patients with persistent atrial fibrillation in terms of single-procedure arrhythmia-free outcome and safety.

METHODS AND RESULTS

A total number of 100 patients undergoing de-novo catheter ablation for persistent AF were randomized in a 1:1 ratio into two different treatment arms: group A: pulmonary vein isolation (PVI) and, if low-voltage areas were present, a substrate modification. Group B: PVI and, if atrial fibrillation persisted, additional ablations, such as linear ablation and/or ablation of non-PV triggers. A total of 50 patients were randomized into each group without significant differences in baseline characteristics. During a mean follow-up of 17.64 ± 4.5 months after a single procedure, 34 (68%) patients of group A were free of arrhythmia recurrence versus 28 (56%) patients in group B (p = ns). In group A, 30 (60%) patients did not show endocardial fibrosis and received solely PVI. Both procedures were performed with a low number of complications; no pericardial effusion or stroke were seen in either group.

CONCLUSIONS

A significant proportion of patients with persistent atrial fibrillation do not show low-voltage areas. A total of 70% of the patients receiving solely PVI did not show any recurrence of atrial fibrillation, and therefore, extensive additional ablation should be avoided in de-novo patients.

Atrial fibrillation: mechanism and clinical management

ABSTRACT

Atrial fibrillation (AF), the most common sustained arrhythmia, is associated with a range of symptoms, including palpitations, cognitive impairment, systemic embolism, and increased mortality. It places a significant burden on healthcare systems worldwide. Despite decades of research, the precise mechanisms underlying AF remain elusive. Current understanding suggests that factors like stretch-induced fibrosis, epicardial adipose tissue (EAT), chronic inflammation, autonomic nervous system (ANS) imbalances, and genetic mutations all play significant roles in its development. In recent years, the advent of wearable devices has revolutionized AF diagnosis, enabling timely detection and monitoring. However, balancing early diagnosis with efficient resource utilization presents new challenges for healthcare providers. AF management primarily focuses on stroke prevention and symptom alleviation. Patients at high risk of thromboembolism require anticoagulation therapy, and emerging pipeline drugs, particularly factor XI inhibitors, hold promise for achieving effective anticoagulation with reduced bleeding risks. The scope of indications for catheter ablation in AF has expanded significantly. Pulsed field ablation, as a novel energy source, shows potential for improving success rates while ensuring safety. This review integrates existing knowledge and ongoing research on AF pathophysiology and clinical management, with emphasis on diagnostic devices, next-generation anticoagulants, drugs targeting underlying mechanisms, and interventional therapies. It offers a comprehensive mosaic of AF, providing insights into its complexities.

Impact of Vein of Marshall Ethanol Infusion Combined with Anatomical Ablation for the Treatment of Persistent Atrial Fibrillation: A Long-Term Follow-Up Based on Implantable Loop Recorders

BACKGROUND

The best ablation treatment for persistent atrial fibrillation (PeAF) patients is still debated. The vein of Marshall (VOM) seems to be a promising target for ablation and could be combined with a linear set of ablation lesions. The aim of our study is to evaluate the incidence of AF recurrences in a PeAF population treated with a comprehensive ablation approach consisting of VOM ethanol infusion (EI), pulmonary vein isolation (PVI), a left atrial (LA) roofline, a mitral line (guided by the newly formed lesion after alcohol infusion into the VOM and validated by pacing), and a cavotricuspid isthmus line.

METHODS

Consecutive patients undergoing the first ablation procedure of catheter ablation (CA) for PeAF were enrolled. All patients underwent VOM-EI, PVI, and ablation lines along the roof of the LA, mitral, and cavotricuspid isthmus. LA voltage mapping before and after VOM-EI was also performed. An implantable loop recorder (ILR) was implanted at the end of the ablation in each patient.

RESULTS

Thirty-one consecutive patients (66 ± 8 years and 71% male) affected by PeAF were included in this study. The VOM-EI procedural phase lasted 21.4 ± 10.1 min. PV isolation and lines were validated in all subjects. The ML block was achieved within 10.8 ± 8.7 min. At a mean follow-up of 12 ± 7 months, 27 out of 31 (87%) patients remained free from AT/AF recurrences. Among the patients with recurrences, two (50%) had incomplete ablation lesions and three (75%) had "suboptimal" VOM-EI. In 23/31 patients (74%), antiarrhythmic drugs (AADs) were discontinued after 1 month of follow-up. No significant complications were reported during the follow-up.

CONCLUSIONS

this single-center experience demonstrates that VOM-EI systematically combined with an anatomical ablation set in patients with PeAF resulted in feasible, safe, and effective freedom from AF/AT recurrences in 87% of the population after a 1-year follow-up period according to an ILR.

Angiographic assessment of vein of Marshall in atrial fibrillation: Implications for identification and cannulation

Background

The vein of Marshall (VOM) ethanol infusion improves rhythm control in atrial fibrillation (AF). The identification and cannulation of the VOM can be technically challenging. This study aimed to assess the angiographic morphology of the VOM and investigate its value in the VOM ethanol infusion.

Methods

Patients with AF (n = 162) scheduled for combined catheter ablation and VOM ethanol infusion were enrolled. The VOM morphologic features in the right anterior oblique (RAO), the left anterior oblique (LAO), and the LAO cranial views were analyzed. The impact of morphology on the identification and cannulation of the VOM was investigated.

Results

The VOM was identified in 159 (98.1 %) and cannulated in 150 (92.6 %) patients. The VOM identification rate in the RAO and LAO/LAO cranial view was 97.3 % and 89.3 %, respectively. Of 134 patients with VOM identification in the LAO/LAO cranial view, 104 (77.6 %) had a VOM ostium clock location (VOMoClock) of ≤3 and 3-4 o'clock. The VOM cannulation success rate in the ≤3, 3-4, 4-5, and 5-6 o'clock groups was 100 %, 92.6 %, 88.5 %, and 77.8 %, respectively (p = 0.032). The median (interquartile range) cannulation time in the four groups was 10.5 (6.3), 12.0 (9.0), 13.0 (23.0), and 34.0 (30.0) minutes, respectively (p < 0.001). The diameter of the coronary sinus ostium in the RAO view and the VOMoClock were independent predictors for difficult cannulation.

Conclusions

The VOM morphologic features in different angiographic views provide valuable information which could facilitate the identification and cannulation of the VOM.

Double-wire technique to facilitate vein of Marshall cannulation and ethanol infusion in atrial fibrillation: a case series

BACKGROUND

The vein of Marshall (VOM) ethanol infusion is increasingly performed in combination with catheter ablation in atrial fibrillation (AF). The cannulation of the VOM can sometimes be challenging. This study aimed to evaluate the double-wire technique in cases of difficult cannulation of the VOM.

CASE PRESENTATION

Patients with AF scheduled for combined catheter ablation and VOM ethanol infusion were consecutively enrolled. The procedure was performed via the femoral vein. If the regular cannulation technique with one angioplasty wire failed or took more than 20 min, the double-wire technique using a stabilizing wire and a cannulation wire was performed. The unique technique was used mainly in two scenarios, when the Eustachian ridge was too prominent as a barrier for catheter manipulation or when the VOM ostium was close to the coronary sinus ostium. Of 162 patients scheduled for VOM ethanol infusion, the double-wire technique was applied in 6 (3.7%) patients and led to a 100% successful cannulation rate of the VOM. Of the six patients, two had a prominent Eustachian ridge, and four had a VOM ostium close to the coronary sinus ostium. The mean cannulation time was 33.3 ± 7.3 min. The ethanol infusion was successfully performed in 5 patients. One patient had a collateral circulation in the distal VOM, and ethanol infusion was not performed.

CONCLUSIONS

The double-wire technique can facilitate VOM cannulation and ethanol infusion in challenging cases.

WORD COUNT

231.

The impact of empirical Marshall vein ethanol infusion as a first-choice intraoperative strategy on the long-term outcomes in patients with persistent atrial fibrillation undergoing mitral isthmus ablation

Background

Marshall vein ethanol infusion (MVEI) as an additional therapy to conventional catheter ablation (CA) has been proved to be efficacious in patients with persistent atrial fibrillation (PeAF). However, whether empirical MVEI could be the first-line strategy in mitral isthmus (MI) ablation has seldom been investigated. Here, we aim to compare the efficacy, safety, and long-term outcomes between provisional and empirical MVEI in PeAF patients undergoing the index MI ablation procedure.

Methods

We enrolled 133 patients with PeAF either in the provisional group (n = 38, MVEI was performed when conventional endocardial and/or epicardial ablation procedures were inadequate to achieve bidirectional MI block) or in the empirical group (n = 95, MVEI was performed empirically before MI CA).

Results

All of the baseline characteristics were comparable. Less spontaneous or inducible atrial tachycardias (ATs) were encountered in the empirical group of patients (P < 0.001). More epicardial ablations were applied (26.3% vs. 9.5%, P = 0.016) and a higher incidence of CA-facilitated restoration of sinus rhythm was recorded (86.8% vs. 11.7%, P < 0.001) in the provisional group of patients. Although more fluoroscopy time (6.4[4.2, 9.3] vs. 9.5[5.9, 11.6] min, P = 0.019) and radiation exposure (69.0[25.3, 160.2] vs. 122.0[62.5, 234.1] mGy, P = 0.010) were documented in the empirical group with comparable procedure time, less time (455.9 ± 192.2 vs. 366.5 ± 161.3 s, P = 0.038) was consumed to achieve bidirectional MI block during endocardial ablation in the provisional group. Incidences of procedure-related complications were similar between the two groups. During a 16.5 ± 4.4-month follow-up, the empirical group of patients showed a significantly higher rate of freedom from AT recurrence (95.8% vs. 81.6%, log-rank P = 0.003), while the rate of freedom from AF or atrial tachyarrhythmias (combining AF and AT) was similar. Both univariate (HR 0.19, 95% CI 0.05-0.64, P = 0.008) and multivariate (HR 0.25, 95% CI 0.07-0.92, P = 0.037) Cox regression analyses indicated that empirical MVEI was independently associated with lower long-term AT recurrence.

Conclusion

Among patients with PeAF who underwent the index MI ablation procedure, empirical MVEI could reduce endocardial MI ablation time and provide greater long-term freedom from AT recurrence.

CLOSE-Guided Pulmonary Vein Isolation to Treat Persistent Atrial Fibrillation: 1-Year Outcome

BACKGROUND

CLOSE-guided pulmonary vein isolation (PVI) is based on contiguous and optimized (Ablation Index-guided) radiofrequency lesions. The efficacy of CLOSE-guided PVI in persistent atrial fibrillation (AF) treatment has been poorly evaluated.

METHODS

In two centers, 50 patients eligible for persistent AF ablation underwent CLOSE-guided PVI (Ablation Index ≥ 450 at the anterior wall, ≥300 at posterior wall, intertag distance ≤ 6 mm). If PVI failed to restore sinus rhythm (SR), electrical cardioversion (ECV) was performed. Atrial substrate modification (ASM) was performed only if PVI and ECV failed to restore SR. Recurrence was defined as any recorded episode of AF, atrial tachycardia (AT) or atrial flutter (AFL) > 30 s on Holter electrocardiographs at 3, 6 and 12 months.

RESULTS

From the 50 patients (64 ± 10 years, 14% long-standing persistent AF), SR was restored by ECV in 34 patients (68%) 56 ± 38 days prior to ablation. On the day of ablation, 42 patients (84%) were on class I-III anti-arrhythmic drug therapy (ADT) and the rhythm was AF in 23/50 patients. PVI was achieved in all patients; after PVI, ECV was required in 21 patients and ASM in 1 patient. The mean procedure time, radiofrequency time and fluoroscopy time were 141 ± 33 min, 23 ± 7 min and 7 ± 6 min, respectively. At 12 months, single-procedure freedom from AF/AT/AFL was 80%, with 19 patients (38%) receiving class I-III ADT.

CONCLUSIONS

In a population of patients with persistent AF monitored with intermittent cardiac rhythm recordings, CLOSE-guided PVI resulted in high single-procedure arrhythmia-free survival at 1 year. Future large-scale studies involving continuous cardiac monitoring are necessary.

A novel catheter ablation strategy for non-paroxysmal atrial fibrillation combining cryoballoon, radiofrequency, and Marshall-vein ethanol ablations

BACKGROUNDS

Catheter ablation for non-paroxysmal atrial fibrillation (non-PAF) remains challenging and more effective strategy has been required to reduce postoperative arrhythmia recurrences. This study aims to investigate the efficacy and safety of a novel extensive ablation strategy for non-PAF, that is based on a combination of cryoballoon (CBA), radiofrequency (RFA), and Marshall-vein ethanol ablations (EA-VOM).

METHODS

The study was a single-center, retrospective observational study. We enrolled 171 consecutive patients who underwent de-novo catheter ablation for non-PAF under conscious sedation with a novel extensive ablation strategy that included CBA for pulmonary vein isolation (PVI) and left atrial roof ablation (LARA), RFA for mitral isthmus (MI) ablation, superior vena cava isolation, and other linear ablations and EA-VOM. Recurrence of atrial arrhythmias over 1 year, procedure outcomes, and procedure-related complications were investigated.

RESULTS

A total of 139 (81.3%) patients remained in sinus rhythm during 1-year follow-up. Of the 139 patients, 51 patients (29.8%) received antiarrhythmic drugs. The mean procedure time was 204 ± 45 min. PVI and LARA ablation by CBA and MI block by RFA and EA-VOM were completed in 171 (100%) and 166 (97.1%) patients, respectively. No serious procedure-related complications were observed except for one case of delayed pericardial effusion.

CONCLUSION

Approximately 80% of the study patients were AF-free during 1-year follow-up period after a single procedure based on the novel extensive ablation strategy combining CBA, RFA, and EA-VOM. This strategy for non-PAF may be preferred in terms of maintenance of sinus rhythm, safety even in high-risk patients, and relatively short procedure time.

A novel stepwise approach incorporating ethanol infusion in the vein of Marshall for the ablation of persistent atrial fibrillation

Introduction

Apart from pulmonary vein isolation (PVI), several step-by-step procedures that aim to modify left atrial substrate have been proposed for the ablation of persistent atrial fibrillation (AF), yet the optimal strategy remains elusive. There are cumulative data suggesting an incremental benefit of adding vein of Marshall (VOM) ethanol infusion to PVI in patients with persistent AF. We sought to evaluate the feasibility and efficacy of a novel stepwise ablation approach, incorporating a VOM alcoholization step, for persistent AF.

Methods

In this single-center study, we prospectively enrolled 66 consecutive patients with symptomatic persistent AF and failure of at least one antiarrhythmic drug (ADD). The ablation procedure consisted of (i) PVI, (ii) left atrial segmentation with VOM ethanol infusion and the deployment of linear radiofrequency lesions across the roof and the mitral isthmus and (iii) electrogram-based ablation of dispersion zones. The first two steps were performed in all patients, whereas the third step was carried out only in those still in AF at the end of the second step. Atrial tachycardias during the procedure were mapped and ablated. At the end of the procedure, cavotricuspid isthmus ablation was additionally performed in all patients. The primary endpoint was 12-month freedom from AF and atrial tachycardia after a single procedure and an initial three-month blanking period.

Results

Total procedure time was 153 ± 38.5 min. Fluoroscopy time was 16 ± 6.5 min and the radiofrequency ablation time was 26.14 ± 0.26 min. The primary endpoint occurred in 54 patients (82%). At 12 months, 65% of patients were off any AAD. In the univariate Cox regression analysis, left ventricular ejection fraction < 40% was the only predictor of arrhythmia recurrence (HR 3.56; 95% CI, 1.04-12.19; p = 0.04). One patient developed a pericardial tamponade and another a minor groin hematoma.

Conclusion

A novel stepwise approach, including a step of ethanol infusion in the VOM, is feasible, safe and provides a high rate of sinus rhythm maintenance at 12 months in patients with persistent AF.

Pulsed-Field Ablation on Mitral Isthmus in Persistent Atrial Fibrillation: Preliminary Data on Efficacy and Safety

BACKGROUND

Pulsed-field ablation (PFA) is a new and promising modality of ablation that has been shown to specifically ablate cardiac tissue while sparing other anatomic structures, thus avoiding thermal ablation-related complications. Recent studies have certified safety and efficacy of PFA for pulmonary vein isolation (PVI) in the setting of paroxysmal atrial fibrillation (AF). However, there are very limited data assessing the feasibility and safety of PFA ablation of different substrates within the left atrium in the setting of persistent AF.

OBJECTIVES

The purpose of this study was to evaluate the feasibility and safety of mitral isthmus (MI) ablation in addition to PVI and posterior wall (PW) ablation with PFA in patients with persistent AF.

METHODS

We prospectively included all consecutive patients with persistent AF who underwent a first ablation procedure with PFA. We performed in all these patients a substrate ablation strategy comprising PVI, PW, and MI ablation with the use of PFA only. The primary feasibility endpoint was obtaining a persistent MI block at the end of the procedure. The safety endpoint was a composite of major safety events.

RESULTS

From November 2021 to September 2022, we included 45 patients. Complete MI block was achieved in all 45 (100%). Three patients presented with complications, among them 2 cases (4.4%) of reversible and nonfatal coronary spasm. During a mean follow-up time of 107.8 ± 59.5 days, a 20% recurrence rate was observed.

CONCLUSIONS

PFA is a feasible and safe ablation approach for mitral isthmus ablation in addition to PVI in patients with persistent AF.

Clinical Influence of Ethanol Infusion in the Vein of Marshall on Left Atrial Appendage Occlusion: Results of Feasibility and Safety during Implantation and at 60-Day Follow-Up

BACKGROUND

Ethanol infusion in the vein of Marshall (EI-VOM) has the advantages of reducing the burden of atrial fibrillation (AF), decreasing AF recurrence, and facilitating left pulmonary vein isolation and mitral isthmus bidirectional conduction block. Moreover, it can lead to prominent edema of the coumadin ridge and atrial infarction. Whether these lesions will affect the efficacy and safety of left atrial appendage occlusion (LAAO) has not yet been reported.

OBJECTIVES

To explore the clinical outcome of EI-VOM on LAAO during implantation and after 60 days of follow-up.

METHODS

A total of 100 consecutive patients who underwent radiofrequency catheter ablation combined with LAAO were enrolled in this study. Patients who also underwent EI-VOM at the same period of LAAO were assigned to group 1 (n = 26), and those who did not undergo EI-VOM were assigned to group 2 (n = 74). The feasibility outcomes included intra-procedural LAAO parameters and follow-up LAAO results involving device-related thrombus, a peri-device leak (PDL), and adequate occlusion (defined as a PDL ≤ 5 mm). Safety outcomes were defined as the composites of severe adverse events and cardiac function. Outpatient follow-up was performed 60 days post-procedure.

RESULTS

Intra-procedural LAAO parameters, including the rate of device reselection, rate of device redeployment, rate of intra-procedural PDLs, and total LAAO time, were comparable between groups. Furthermore, intra-procedural adequate occlusion was achieved in all patients. After a median of 68 days, 94 (94.0%) patients received their first radiographic examination. Device-related thrombus was not detected in the follow-up populations. The incidence of follow-up PDLs was similar between the two groups (28.0% vs. 33.3%, p = 0.803). The incidence of adequate occlusion was comparable between groups (96.0% vs. 98.6%, p = 0.463). In group 1, none of the patients experienced severe adverse events. Ethanol infusion significantly reduced the right atrial diameter.

CONCLUSIONS

The present study showed that undergoing an EI-VOM procedure did not impact the operation or effectiveness of LAAO. Combining EI-VOM with LAAO was safe and effective.

Pulmonary vein isolation alone or in combination with substrate modulation after electrical cardioversion failure in patients with persistent atrial fibrillation: The PACIFIC trial: Study design

INTRODUCTION

Pulmonary vein isolation (PVI) is effective at treating 50% of unselected patients with persistent atrial fibrillation (AF). Alternatively, PVI combined with a new ablation strategy entitled the Marshall-PLAN ensures a 78% 1-year sinus rhythm (SR) maintenance rate in the same population. However, a substantial subset of patients could undergo the Marshall-PLAN unnecessarily. It is therefore essential to identify those patients who can be treated with PVI alone versus those who may truly benefit from the Marshall-PLAN before ablation is performed. In this context, we hypothesized that electrical cardioversion (EC) could help to select the most appropriate strategy for each patient.

METHODS

In this multicentre, prospective, randomized study, patients with AF recurrence within 4 weeks after EC will be randomized 1:1 to PVI alone or the Marshall-PLAN. Conversely, patients in whom SR is maintained for ≥4 weeks after EC will be treated with PVI only and included in a prospective registry. The primary endpoint will be the 1-year SR maintenance rate after a single ablation procedure.

RESULTS AND CONCLUSION

The Marshall-PLAN might be necessary in patients with an advanced degree of persistent AF (i.e., where SR is not maintained for ≥4 uninterrupted weeks after EC). Conversely, in patients with mild or moderate persistent AF (i.e., where SR is maintained for ≥4 weeks after EC), PVI alone might be a sufficient ablation strategy. The PACIFIC trial is the first study designed to assess whether rhythm monitoring after EC could help to identify patients who should undergo adjunctive ablation strategies beyond PVI.

Intrinsic Cardiac Neuromodulation in the Management of Atrial Fibrillation- A Potential Missing Link?

Atrial fibrillation (AF) is the most common supraventricular arrhythmia that is linked with higher cardiovascular morbidity and mortality. Recent evidence has demonstrated that catheter-based pulmonary vein isolation (PVI) is not only a viable alternative but may be superior to antiarrhythmic drug therapy for long-term freedom from symptomatic AF episodes, a reduction in the arrhythmia burden, and healthcare resource utilization with a similar risk of adverse events. The intrinsic cardiac autonomic nervous system (ANS) has a significant influence on the structural and electrical milieu, and imbalances in the ANS may contribute to the arrhythmogenesis of AF in some individuals. There is now increasing scientific and clinical interest in various aspects of neuromodulation of intrinsic cardiac ANS, including mapping techniques, ablation methods, and patient selection. In the present review, we aimed to summarize and critically appraise the currently available evidence for the neuromodulation of intrinsic cardiac ANS in AF.

Risk and benefit of extrapulmonary vein ablation in atrial fibrillation

PURPOSE OF REVIEW

This review aims to summarize the recent development, benefit, and safety of extrapulmonary vein ablation for atrial fibrillation.

RECENT FINDING

Studies have shown that extrapulmonary vein ablation can help maintain normal sinus rhythm for patients with persistent atrial fibrillation. As prior strategies targeting anatomical lines and triggers are well utilized, novel techniques for substrate mapping have been rapidly developing. These strategies are well tolerated and could be chosen based on patients' conditions and physicians' experience.

SUMMARY

Extrapulmonary vein ablation could be safely and effectively performed for patients with atrial fibrillation. It provides further consolidation of normal sinus rhythm.

Vein of Marshall Collateralization during Ethanol Infusion in Atrial Fibrillation: Solution for Effective Myocardium Staining

BACKGROUND

The vein of Marshall (VOM) ethanol infusion improves sinus rhythm maintenance in patients with atrial fibrillation (AF). Distal collateral circulation of VOM can be a challenge to effective ethanol infusion.

OBJECTIVE

This study aimed to evaluate the feasibility and efficacy of ethanol infusion in VOM with distal collateral circulation.

METHODS

Patients with AF scheduled for catheter ablation and VOM ethanol infusion were consecutively enrolled. During the procedure, non-occluded coronary sinus angiography was first performed for VOM identification. After VOM identification, an over-the-wire angioplasty balloon was used for cannulation and occluded angiography of the VOM. Those with distal VOM collateral circulation were included in this study. A method of slower ethanol injection (2 mL over 5 min) plus additional balloon occlusion time for 3 min after each injection was used.

RESULTS

Of 162 patients scheduled for VOM ethanol infusion, apparent distal VOM collateral circulation was revealed in seven (4.3%) patients. Five patients had collateral circulation to the left atrium, one to the right superior vena cava, and one to the great cardiac vein. Two patients did not undergo further ethanol infusion because of our inadequate experience during the early stage of the project. Five patients had successful VOM ethanol infusion with manifest localized myocardium staining.

CONCLUSIONS

Ethanol infusion in VOM with distal collateral circulation can be solved by slow injection of ethanol and enough balloon occlusion time between multiple injections.

Simplified stepwise anatomical ablation strategy for mitral isthmus: efficacy, efficiency, safety, and outcome

AIMS

Bidirectional and durable block of mitral isthmus (MI) is essential for catheter ablation of persistent atrial fibrillation (PeAF) and perimitral flutter (PMF), but it remains a challenge. The aim of this study was to create a simple anatomical ablation strategy with minimal fluoroscopy that would yield a high success rate for MI block.

METHODS AND RESULTS

Patients with PeAF or PMF were included. Mitral isthmus was ablated in a stepwise strategy. In Step 1, endocardial MI linear ablation was performed; in Step 2, ablation was targeted to the posterolateral portion of the left atrium along the MI line; in Step 3, epicardial ablation within the coronary sinus (CS) was performed across the MI line to the ostium of the vein of Marshall (VOM) or performed within the VOM if available; in Step 4, the catheter was rotated and ablated in the CS to isolate the CS; and in Step 5, the early activation site with complex component potential above the MI line during distal CS pacing was considered as the ablation target. All patients were followed up. A total of 178 (17 patients with mechanical prosthetic mitral valve) were included. One hundred and sixty-six patients achieved a confirmed MI bidirectional conduction block (93%). One patient had cardiac tamponade. Four patients showed re-conduction across the MI line during a repeated ablation. In the latest follow-up [12 (7, 16) months], 161 of 178 (90%) patients maintained their sinus rhythm.

CONCLUSION

A simple stepwise anatomical ablation strategy for MI shows a high success rate with low fluoroscopy exposure.

Optimization of intra-operative electrophysiological localization of the ligament of Marshall

Background

The ligament of Marshall (LOM) may play a role in the pathophysiology of several tachyarrhythmias and accurate electrophysiological localization of this structure is crucial for effective ablation therapy. This study therefore quantifies electrophysiological properties of the LOM, and identifies which electrogram (EGM) recording (uni- or bipolar) and processing technologies [local activation time (LAT) and/or voltage mapping] are most suitable for accurate localization of the LOM.

Methods

The LOM was electrophysiologically identified in 19 patients (mean age 66 ± 14 years; 12 male) undergoing elective cardiac surgery using intra-operative high-density epicardial mapping, to quantify and visualize EGM features during sinus rhythm.

Results

Only a third of LOM potentials that were visualized using unipolar EGMs, were still visible in bipolar activation maps. Unipolar LOM potentials had lower voltages (P50: LOM: 1.51 (0.42–4.29) mV vs. left atrium (LA): 8.34 (1.50–17.91) mV, p < 0.001), less steep slopes (P50: LOM: –0.48 (–1.96 to –0.17) V/s vs. LA: –1.24 (–2.59 to –0.21) V/s, p < 0.001), and prolonged activation duration (LOM: 20 (7.5–30.5) ms vs. LA: 16.5 (6–28) ms, p = 0.008) compared to LA potentials. Likewise, bipolar LOM voltages were also smaller (P50: LOM: 1.54 (0.48–3.28) mV vs. LA: 3.12 (0.50–7.19) mV, p < 0.001).

Conclusion

The LOM was most accurately localized in activation and voltage maps by using unipolar EGMs with annotation of primary deflections in case of single potentials and secondary deflections in case of double or fractionated potentials.