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.

Activation patterns and electrophysiological characteristics of Marshall Bundle related left atrial tachycardias post atrial fibrillation ablation

BACKGROUND

Epicardial Marshall bundle (MB) are frequently utilized in left atrial tachycardias (LATs) post atrial fibrillation (AF) ablation with pulmonary vein isolation and substrate modification.

OBJECTIVE

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

METHODS

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

RESULTS

Three activation patterns were identified with a critical isthmus via MB: 1）peri-mitral macro-reentry (PM LAT) (n=20, 71.4%); 2) Left atrial appendage (LAA)-related reentry (n=5, 17.9%); and 3) Left pulmonary vein (LPV)-related reentry (n=3,10.7%). In 18 patients, a characteristic triple potential observed along the previously endocardial LA ridge block line was composed of near-field double potentials and far-field MB potential. These findings were further delineated in 24 patients with either cannulation in the VOM (19 patients) or epicardial mapping(5 patients). Ethanol infusion of the VOM resulted in AT termination in 20/28 patients.

CONCLUSION

Different types of MB-Mediated LATs post AF-ablation could be identified by ultra- high density mapping. Ethanol infusion within the VOM was effective in eliminating these tachycardias.

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.

Comparison of anterior mitral line and mitral isthmus line for ablation of mitral annular flutter

BACKGROUND

Mitral annular flutter (MAF) is the most common left atrial macro-reentrant arrhythmia following catheter ablation of atrial fibrillation (AF). The best ablation approach for this arrhythmia remains unclear.

METHODS

This single-center, retrospective study sought to compare the acute and long-term outcomes of patients with MAF treated with an anterior mitral line (AML) versus a mitral isthmus line (MIL). Acute ablation success, complication rates, and long-term arrhythmia recurrence were compared between the two groups.

RESULTS

Between 2015 and 2021, a total of 81 patients underwent ablation of MAF (58 with an AML and 23 with a MIL). Acute procedural success defined as bidirectional block was achieved in 88% of the AML and 91% of the MIL patients respectively (p = 1.0). One year freedom from atrial arrhythmias was 49.5% versus 77.5% and at 4 years was 24% versus 59.6% for AML versus MIL, respectively (hazard ratio [HR]: 0.38, confidence interval [CI]: 0.17-0.82, p = .009). Fewer patients in the MIL group had recurrent atrial flutter when compared to the AML group (HR: 0.32, CI: 0.12-0.83, p = .009). The incidence of recurrent AF, on the other side, was not different between both groups (21.7% vs. 18.9%; p = .76). There were no serious adverse events in either group.

CONCLUSION

In this retrospective study of patients with MAF, a MIL compared to AML was associated with a long-term reduction in recurrent atrial arrhythmias driven by a reduction in macroreentrant atrial flutters.

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.

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.

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 .

Efficacy and feasibility of vein of Marshall ethanol infusion during persistent atrial fibrillation ablation: A systematic review and meta-analysis

BACKGROUND

Catheter ablation (CA) is currently used to treat persistent atrial fibrillation (PeAF). However, its effectiveness is limited. This study aimed to estimate the effectiveness of the vein of Marshall absolute ethanol injection (VOM-EI) for PeAF ablation.

HYPOTHESIS

Adjunctive vein of Marshall ethanol injection (VOM-EI) strategies are more effective than conventional catheter ablation (CA) and have similar safety outcomes.

METHODS

We extensively searched the literature for studies evaluating the effectiveness and safety of VOM-EI + CA compared with CA alone. The primary endpoint was the rate of acute bidirectional block of the isthmus of the mitral annulus (MIBB). The secondary endpoints were atrial fibrillation (AF) or atrial tachycardia (AT) recurrence over 30 seconds after a 3-month blanking period. Weighted pooled risk ratios (RRs) and corresponding 95% confidence intervals (CIs) were calculated using a random effects model.

RESULTS

Based on the selection criteria, nine studies were included in this systematic review, including patients with AF (n = 2508), persistent AF (n = 1829), perimitral flutter (n = 103), and perimitral AT (n = 165). There were 1028 patients in the VOM-EI + CA group and 1605 in the CA alone group. The VOM-EI + CA group showed a lower rate of AF/AT relapse (RR = 0.70; 95% CI = 0.53-0.91; p = .008) and a higher rate of acute MIBB (RR = 1.29; 95% CI = 1.11-1.50; p = .0007) than the CA alone group.

CONCLUSION

Our meta-analysis revealed that adjunctive VOM-EI strategies are more effective than conventional CA and have similar safety outcomes.

Comparison of the effect of ethanol infusion into the vein of Marshall between with and without collateral veins

BACKGROUND

Despite the potential benefits of ethanol infusion into the vein of Marshall (EIVOM) for atrial fibrillation (AF) ablation, concerns about its reversible and unpredictable effects persist.

OBJECTIVE

To assess the effectiveness of EIVOM in the vein of Marshall (VOM) with collateral veins (CVs) during mitral isthmus and AF ablation.

METHODS

We included 142 AF patients. EIVOM was performed before radiofrequency ablation, and low-voltage areas (<0.5 mV) were measured before, immediately after, and 1 h after EIVOM.

RESULTS

Among the 142 patients, 93 (65%) underwent EIVOM, and among these, 35 (37%) were found to have CVs. In the VOM with CVs group, areas with low voltage measured 0 (0-1.85) cm2 before EIVOM, 6.9 (4.1-11.2) cm2 immediately after EIVOM, and 5.7 (3.5-10.6) cm2 1 h after EIVOM. Conversely, in the group designated as VOM without CVs-from which the nine leakage cases were excluded-the areas measured 0 (0-1.35) cm2 , 5.5 (2.6-11.8) cm2 , and 4.7 (1.8-13.5) cm2 at the respective time points. MI line block was fully achieved in 89% (31/35) of cases in the VOM with CVs group and 88% (44/49) in the VOM without CVs groups (p = .94). There was no significant difference in the outcome of AF ablation between these groups (log-rank p = .73). Additionally, no significant difference was observed between EIVOM (+) and EIVOM (-) groups (log-rank p = .59).

CONCLUSION

EIVOM effectively creates MI line block, and its beneficial effects are sustained for at least 1 h after the procedure despite the low-voltage areas showing a slight reduction in size.

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.

A novel stepwise catheter ablation method of the mitral isthmus for persistent atrial fibrillation: efficacy and reproducibility

BACKGROUND

Ethanol infusion of the vein of Marshall (EI-VOM) has been widely used to facilitate mitral isthmus (MI) ablation. According to the literature, the success rate of achieving a bidirectional conduction block across the MI ranges from 51 to 96%, with no standardized strategy or method available for cardiac electrophysiologists.

OBJECTIVES

This study aimed to introduce and evaluate a novel ablation method of MI.

METHODS

Consecutive patients with persistent atrial fibrillation (PeAF) that underwent catheter ablation were included. The MI ablation procedure followed a stepwise approach. In step 1, ethanol infusion of the vein of Marshall (EI-VOM) was performed. In step 2, a "V-shape" endocardial linear ablation connecting the left inferior pulmonary vein (LIPV) to mitral annulus (MA) was performed. In step 3, earliest activation sites(EASs) near the ablation line were identified using activation mapping followed by reinforced ablation. In step 4, precise epicardial ablation was performed, with the catheter introduced into the coronary sinus(CS) to target key ablation targets (KATs).

RESULTS

135 patients with PeAF underwent catheter ablation with the stepwise ablation method adopted in 119 cases. Bidirectional conduction blocks were achieved in 117 patients (98.3%). The block rates of every step were 0%, 58.0%, 44.0%, and 92.9%, and the cumulative block rates for the four steps were 0%, 58.0%, 76.5%, and 98.3%, respectively. No patient experienced fatal complications.

CONCLUSIONS

Our novel stepwise catheter ablation method for MI yielded a high bidirectional block rate with high reproducibility.

Efficacy and durability of posterior wall isolation with ethanol infusion into the vein of Marshall

INTRODUCTION

Ethanol infusion into the vein of Marshall (EIVOM) is expected to be an adjunctive therapy for mitral isthmus (MI) ablation. Additionally, EIVOM can widely ablate the epicardium via the branches that extend to the left atrial posterior wall (LAPW) and facilitate LAPW isolation. This study aimed to investigate the efficacy and durability of LAPW isolation with EIVOM.

METHODS

Our cohort consisted of 413 patients with atrial fibrillation (AF) who underwent both LAPW and MI ablations. EIVOM was first attempted in 177 (35%) patients with adequate VOMs. The VOM was infused with 5 mL of ethanol with a double coaxial guiding catheter technique. Both ablations were performed only by radiofrequency ablation (the RF group) in the remaining 236 (57%) patients.

RESULTS

EIVOM with 5 mL of ethanol was completely achieved in 106 patients (the EIVOM group). The application duration of LAPW isolation did not differ significantly between the two groups (718 ± 276 vs. 709 ± 288 s; p = .78). LAPW debulking ablation was required in 64/106 (60%) and 176/236 (75%) patients in the EIVOM and RF groups, respectively (p < .05). However, AF- or atrial tachycardia-free survival analyses revealed no significant differences between the two groups (log-rank p = .70). Among the cases of recurrence, 17 and 38 patients underwent subsequent ablation sessions; LAPW was reconnected in 9/17 (53%) and 25/38 (53%) patients (p = .36) in the EIVOM and RF groups, respectively.

CONCLUSION

EIVOM reduced the number of cases that required LAPW debulking ablation but did not improve the durability of LAPW isolation or clinical outcomes.

Vein of Marshall ethanol infusion: First-step or adjunctive choice for perimitral atrial tachycardia?

BACKGROUND

Perimitral atrial tachycardia (PMAT) is the most frequent type of iatrogenic atrial tachycardia (AT) after atrial fibrillation (AF) ablation. Vein of Marshall ethanol infusion (EIVOM) is a promising technique in mitral isthmus (MI) ablation.

METHODS

A total of 165 patients with PMAT were divided into three groups according to ablation strategies, including RF only group (n = 89), RF-EIVOM group (initial RF ablation with adjunctive EIVOM, n = 28), and EIVOM-RF group (first-step EIVOM with touch-up RF ablation, n = 48). Acute and follow-up procedure outcomes were evaluated.

RESULTS

PMAT terminated in 89.9%, 89.3%, and 93.7% of patients in RF only, RF-EIVOM and EIVOM-RF groups, respectively (p = .715), with complete MI block achieved in 80.9%, 89.3%, and 95.8% of patients (EIVOM-RF vs. RF only, p = .012). First-step utilization of EIVOM was associated with a significant shortening of RF ablation time at MI (EIVOM-RF 2.1 ± 1.3 min, RF only 7.9 ± 5.9 min, RF-EIVOM 6.8 ± 5.8 min; p < .001) and a decrease in the proportion of patients need ablation within coronary sinus (CS, EIVOM-RF 14.6%, RF only 61.8%, RF-EIVOM 64.3%; p < .001). After a mean follow-up of 12.1 ± 6.2 months, AF/AT recurred in 39 (43.8%), 6 (21.4%), and 12 (25.0%) patients in RF only, RF-EIVOM, and EIVOM-RF group (RF-EIVOM vs. RF only, p = .026; EIVOM-RF vs. RF only, p = .022).

CONCLUSIONS

EIVOM was associated with an enhanced acute MI block rate as well as reduced AF/AT recurrence. First-step utilization of EIVOM promises to significantly simplify the RF ablation process.

CONDENSED ABSTRACT

PMAT is the most common type of iatrogenic AT after AF ablation procedures. EIVOM contributed to a higher acute MI block rate and lower arrhythmia recurrence risk during follow-up. First-step utilization of EIVOM significantly reduced the need for radiofrequency ablation at MI and inside CS with the advantage of creating a homogenous, transmural lesion and eliminating epicardial connections.

The adjunctive effect for left pulmonary vein isolation of vein of Marshall ethanol infusion in persistent atrial fibrillation

OBJECTIVE

This study sought to assess the effect of ethanol infusion into the vein of Marshall (EIVOM) on the acute success of left pulmonary vein (LPV) isolation in persistent atrial fibrillation (PeAF).

METHODS AND RESULTS

A total of 313 patients with drug-resistant PeAF were enrolled (135 in Group 1 and 178 in Group 2). In Group 1, EIVOM was firstly performed, followed by radiofrequency ablation (RFA) including bilateral pulmonary vein isolation (PVI) and linear ablation at roofline, cavotricuspid isthmus, and mitral isthmus (MI). In Group 2, PVI and linear ablations were completed with RFA. First-pass isolation of the LPV was achieved in 119 (88.1%) and 132 (74.2%) patients in Groups 1 and 2, respectively (P = 0.002). The rate of acute pulmonary vein reconnection (PVR) was significantly lower in Group 1 (9.6% vs. 22.5%, P = 0.003). About half of acute PVR occurred in the carina with or without EIVOM.

CONCLUSION

EIVOM is effective in achieving a higher first-pass isolation and a lower acute PVR of LPV in PeAF.

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.

Distribution of atrial low voltage induced by vein of Marshall ethanol infusion

INTRODUCTION

Systematic and quantitative descriptions of vein of Marshall (VOM)-induced tissue ablation are lacking. We sought to characterize the distribution of low voltage observed in the left atrium (LA) after VOM ethanol infusion.

METHODS AND RESULTS

The distribution of ethanol-induced low voltage was evaluated by comparing high-density maps performed before and after VOM ethanol infusion in 114 patients referred for atrial fibrillation ablation. The two most frequently impacted segments were the inferior portion of the ridge (82.5%) and the first half of the mitral isthmus (pulmonary vein side) (92.1%). Low-voltage absence in these typical areas resulted from inadvertent ethanol infusion in the left atrial appendage vein (n = 3), initial VOM dissection (n = 3), or a "no branches" VOM morphology (n = 1). Visible anastomosis of the VOM with roof or posterior veins more frequently resulted in low-voltage extension beyond typical areas, toward the entire left antrum (19.0% vs. 1.9%, p = .0045) or the posterior LA (39.7% vs. 3.8%, p < .001) but with a limited positive predictive value ranging from 29.4% to 43.5%. Ethanol-induced low voltage covered a median LA surface of 3.6% (1.9%-5.0%) and did not exceed 8% of the LA surface in 90% of patients.

CONCLUSION

VOM ethanol infusion typically locates at the inferior ridge and the adjacent half of the mitral isthmus. Low-voltage extensions can be anticipated but not guaranteed by the presence of visible anastomosis of the VOM with roof or posterior veins.

The Long-Term Outcomes of Ablation With Vein of Marshall Ethanol Infusion vs. Ablation Alone in Patients With Atrial Fibrillation: A Meta-Analysis

Background

The long-term outcomes of ablation with vein of Marshall ethanol infusion (VOM-ABL) compared with ablation alone in patients with atrial fibrillation (AF) remains elusive. We aimed to explore whether VOM-ABL showed better long-term benefits and screen the potential determinants of outcome impact of VOM-ABL procedure.

Methods

PubMed, Cochrane Library, Web of Science, and Embase were searched up to 1st September 2021. Studies comparing the long-term (one-year or longer) outcomes between VOM-ABL and ablation alone were included. Subgroup analysis identified potential determinants for VOM-ABL procedure.

Results

Compared with ablation alone, VOM-ABL was associated with a significantly higher rate of long-term freedom from AF/AT (risk ratio [RR], 1.28; 95% confidence interval [CI], 1.12–1.47; p = 0.00) and successful mitral isthmus (MI) block (RR, 1.52; 95% CI, 1.16–1.99; p = 0.00), whereas, there was no significant difference in pericardial effusion, stroke/transient ischemic attack (TIA), and all-cause death. Subgroup analysis identified two significant treatment-covariate interactions: one was ablation strategy subgroup (pulmonary vein isolation plus linear and/or substrate ablation [PVI+]; RR, 1.41; 95% CI, 1.27–1.56 vs. PVI; RR, 1.05; 95% CI, 0.92–1.19, p = 0.00 for interaction) for freedom from AF/AT, while the other was VOM-ABL group sample size subgroup (≥ 100; RR, 1.98; 95% CI, 1.24–3.17 vs. <100; RR, 1.20; 95% CI, 1.10–1.30, p = 0.04 for interaction) for MI block.

Conclusions

This meta-analysis demonstrates that VOM-ABL has superior efficacy and comparable safety over ablation alone in AF patients with long-term follow-up. Moreover, PVI+ and VOM-ABL group sample size ≥ 100 may be associated with a great impact on freedom from AF/AT and MI block, respectively.

Adjunctive Vein of Marshall Ethanol Infusion During Atrial Fibrillation Ablation: A Systematic Review and Meta-Analysis

Introduction

Catheter ablation (CA) for atrial fibrillation (AF) can be associated with limited efficacy. Due to its autonomic innervation, the vein of Marshall (VOM) is an attractive target during AF ablation. In this meta-analysis, we aimed to evaluate the efficacy and safety of adjunctive ethanol infusion of VOM (VOM-EI) in AF ablation.

Methods

We performed a comprehensive literature search for studies that evaluated the efficacy and safety of VOM-EI in AF ablation compared to AF catheter ablation alone. The primary outcome of interest was late (≥3 months) AF or atrial tachycardia (AT) recurrence. The secondary outcomes included acute mitral isthmus bidirectional block (MIBB) and procedural complications (pericardial effusion, stroke, or atrio-esophageal fistula). Pooled relative risk (RR) and corresponding 95% confidence intervals (CIs) were calculated using the random-effects model.

Results

A total of four studies, including 804 AF patients (68.2% with persistent AF, the mean age of 63.5±9.9 years, 401 patients underwent VOM-EI plus CA vs. 403 patients who had CA alone), were included in the final analysis. VOM-EI group was associated with a lower risk of late AF/AT recurrence (RR:0.63; 95% CI:0.46-0.87; P = 0.005), and increased probability to achieve acute MIBB (RR:1.39; 95% CI:1.08-1.79; P = 0.009) without an increase in procedural complications (RR:1.05; 95% CI:0.57-1.94; P = 0.87).

Conclusions

Our meta-analysis demonstrated that adjunctive VOM-EI strategy is more effective than conventional catheter ablation with similar safety profiles.

Durability of Left Atrial Lesions After Ethanol Infusion in the Vein of Marshall

OBJECTIVES

The aim of this study was to assess the persistence of left atrial (LA) lesions created by ethanol infusion in the vein of Marshall (EIVM) by electroanatomical mapping on repeat catheter ablation for recurrent atrial tachyarrhythmia.

BACKGROUND

Little is known about the durability of LA lesions created by EIVM.

METHODS

The study included consecutive patients who underwent EIVM for persistent atrial fibrillation or perimitral LA flutter (index procedure) and repeat catheter ablation for recurrent atrial tachyarrhythmia or atrial fibrillation at a single center between January 2019 and April 2020. The acute effect of EIVM was assessed at the index procedure by comparing the area of bipolar voltage <0.05 mV in the vein of Marshall (VOM) region before and immediately after EIVM. The long-term effect of EIVM was assessed by comparing this area in the VOM region between the redo procedure and the index procedure.

RESULTS

Twenty-four consecutive patients (mean age 68.6 ± 6.1 years, 58% men) underwent redo procedures after previous EIVM for persistent atrial fibrillation (n = 21 [88%]) or perimitral LA flutter (n = 5 [21%]). In each patient, the EIVM-related lesion persisted, with a chronic scar in the VOM region (median 13.1 cm² [interquartile range: 8.1-15.9 cm²] vs 12.4 cm² [interquartile range: 7.6-15.7 cm²] acutely, respectively). One quarter of patients (9 of 20) had late mitral isthmus reconnection, which was located at the mitral annular edge or in the coronary sinus.

CONCLUSIONS

Atrial lesions created by EIVM are durable, which reinforces the efficacy profile of EIVM. Reconduction sites in the mitral isthmus are located at the edge of the scar and in the coronary sinus.

Durability of mitral isthmus ablation with and without ethanol infusion in the vein of Marshall

INTRODUCTION

Ethanol infusion in the vein of Marshall (EIVOM) effectively creates a linear ablation lesion in the mitral isthmus (MI). However, data on the long-term success rates of MI ablation is limited.

METHODS AND RESULTS

Our cohort consisted of 560 patients with nonparoxysmal atrial fibrillation (AF) who underwent an initial MI ablation. Ablations were performed by only radiofrequency (RF) in 384 (RF group) or by RF and EIVOM in 176 (EIVOM/RF group) patients; 5 ml anhydrous ethanol was used to perform EIVOM in advance of RF. Following EIVOM, RF pulses were delivered to the lateral MI line. Bidirectional MI block was fully achieved in 353/384 (92%) (First 318, Re-do 35) patinents in the RF group and 171/176 (97%) (First 128, Re-do 43) patients in the EIVOM/RF group (p = .09 in the first, p = .10 in the re-do ablation cases). In cases with complete MI line block, recurrent AF or atrial tachycardia was observed in 130/353 (37%) patients in the RF group and in 64/171 (37%) patients in the EIVOM/RF group (log-rank p = .12 in the first, and p = .30 in the re-do ablation cases). Of the total 560 patients, 123 proceeded to the subsequent ablation session. Reconduction across MI line block was observed in 39/80 (49%) patients in the RF group and 25/43 (58%) patients in the EIVOM/RF group (p = .32).

CONCLUSION

EIVOM effectively ensures MI line block; however, the reconduction rate was similar between the two groups.

What are the post-ablation insular residual electrograms in the posterior left pulmonary veins electrically connected to?

A 67-year-old man underwent a third ablation procedure for a recurrent atrial tachycardia (AT) after an extensive pulmonary vein (PV) isolation, linear ablation along the left atrial (LA) roof and posterolateral mitral isthmus (MI), and defragmentation of persistent atrial fibrillation and an induced perimitral AT. High-resolution mapping during the clinical AT using the Rhythmia system (Boston Scientific) suggested that the AT was a ridge-related reentrant AT and exhibited a reconnection of the left PVs (LPVs). The residual electrograms in the posterior LPVs were surrounded by endocardial scar, which was like an island consisting of residual LPV electrograms. Retrograde venography of the vein of Marshall (VOM) demonstrated that the VOM reached the posterior left superior PV through the ridge between the LA appendage and left inferior PV and then the LPV carina. An ethanol infusion into the VOM resulted in a simultaneous AT termination and complete electrical isolation of the LPVs, that is, the disappearance of the residual LPV electrograms. The insular residual LPV electrograms in the present case did not appear to be endocardially connected to the LA, because the LPV electrograms were surrounded by endocardial scar and there was a large time gap between the earliest activation in the posterior LPVs and activation in the surrounding area. The VOM course on the venography and elimination of the residual LPV electrograms with an ethanol infusion into the VOM suggested that the insular residual LPV electrograms were electrically connected to the posterolateral LA via the VOM and its branches.

Efficacy and safety of ethanol infusion into the vein of Marshall for mitral isthmus ablation

INTRODUCTION

Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM-EI) can facilitate the achievement of mitral isthmus block. This study sought to describe the efficacy and safety of this technique.

METHODS AND RESULTS

Twenty-two consecutive patients (14 males, median age 71 years) with attempted VOM-EI for mitral isthmus ablation were included in the study. VOM-EI was successfully performed with a median of 4 ml of 96% ethanol in 19 patients (86%) and the mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM-EI was necessary for 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM-EI and terminated or slowed by VOM-EI in 4 and 3 patients, respectively. The low-voltage area of the mitral isthmus region increased from 3.1 cm² (interquartile range [IQR] 0-7.9) before to 13.2 cm² (IQR: 8.2-15.0) after VOM-EI and correlated significantly with the volume of ethanol injected (p = .03). Median high-sensitive cardiac troponin-T increased significantly from 330 ng/L (IQR: 221-516) the evening of the procedure to 598 ng/L (IQR: 382-769; p = .02) the following morning. A small pericardial effusion occurred in three patients (16%), mild pericarditis in one (5%), and uneventful VOM dissection in two (11%). After a median follow-up of 3.5 months (IQR: 3.0-11.0), 10 of 18 patients (56%) with VOM-EI and available follow-up had arrhythmia recurrence. Repeat ablation was performed in five patients (50%) and peri-mitral flutter diagnosed in three (60%).

CONCLUSION

VOM-EI is feasible, safe, and effective to achieve acute mitral isthmus block.

Differentiating atrial tachycardias with centrifugal activation: Lessons from high-resolution mapping

BACKGROUND

Centrifugal activation is not always the origin of a focal atrial tachycardia (AT) ("true-focal"), but passive activation from the other structures ("pseudo-focal").

OBJECTIVE

We aimed to establish a method to differentiate true-focal from pseudo-focal.

METHODS

In 49 centrifugal activations in 35 patients with AT, 12-lead electrocardiogram, activation map, atrial global activation histogram (GAH), and local electrograms were analyzed. GAH demonstrates the relation between the activation area and timing through the cycle length, displayed with a normalized value, ranging from 0 (smallest activation area) to 1.0 (largest activation area).

RESULTS

Of 30 centrifugal activations observed in the septal region, 6/30 (20.0%) were true-focal. The remaining 24/60 (80.0%) were pseudo-focal, of which 23 (95.8%) were from the opposite chamber. P-wave/flutter-wave duration < 200 ms discriminated true-focal from pseudo-focal (sensitivity 100%; specificity 54.5%; positive predictive value 33.3%; negative predictive value 100%). Multiple breakthrough ruled out the possibility of a true-focal AT. Other differentiating factors were an activation area within the initial 20 ms of <5 mm² and a typical QS pattern electrogram at the origin. Of 19 centrifugal activations observed outside the septal regions, 7 were true-focal and 12 were pseudo-focal exited from an epicardial structure: 10 of 12 (83.3%) were located around the left atrial appendage and ridge. Flutter wave, GAH score ≤ 0.05, and GAH score < 0.1 for >110 ms of cycle length differentiated true-focal from pseudo-focal with a sensitivity/negative predictive value of 100%. GAH score < 0.1 for >40% of the cycle length simply discriminated true-focal from pseudo-focal with 100% accuracy.

CONCLUSION

Centrifugal activation is not necessarily due to a focal AT but passive activation. The activation map with GAH in addition to the 12-lead electrocardiogram and local electrograms enables an accurate differentiation.

Significance of manifest localized staining during ethanol infusion into the vein of Marshall

BACKGROUND

Localized staining due to venule injury is attributable to ethanol infusion into the vein of Marshall (Et-VOM).

OBJECTIVE

The purpose of this study was to investigate adverse outcomes of localized staining during Et-VOM in patients undergoing ablation for atrial fibrillation.

METHODS

Two hundred four patients (age 64 ± 10 years; 153 male) were sorted based on the aspect of localized staining. Staining of atrial myocardium that spread uniformly along the VOM vascular tree following selective VOM venography was considered normal, in contrast to predominantly localized staining that spread concentrically from a focal point due to vascular injury. Outcomes between the 2 groups were compared.

RESULTS

Localized staining was observed in 27% of patients. No patients developed clinically significant pericardial effusions during Et-VOM; however, 7 patients developed pericardial effusions on the first postprocedural day (3.6% in patients with vs 3.4% in patients without localized staining). No significant difference was found in achievement of acute mitral isthmus (MI) block (96% vs 98%) and size of the endocardial low-voltage area (8.5 ± 4.1 cm² vs 9.3 ± 5.3 cm²) in patients with and without localized staining, respectively. Long-term follow-up was not impacted by localized staining. Freedom from recurrent atrial tachyarrhythmias (66% vs 76%) and durability of MI block (57% vs 54%) were not significantly different with and without localized staining. There were no cases of rehospitalization for pericarditis, chronic pericardial effusion, or heart failure.

CONCLUSION

In our study, localized staining was frequent but was not associated with clinically relevant impact or disadvantages.

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

BACKGROUND

Beyond pulmonary vein isolation (PVI), the optimal ablation strategy for persistent atrial fibrillation (AF) remains poorly defined.

OBJECTIVE

The purpose of this study was to examine a novel comprehensive ablation strategy (Marshall bundle elimination, Pulmonary vein isolation, and Line completion for ANatomical ablation of persistent atrial fibrillation [Marshall-PLAN]) strictly based on anatomical considerations.

METHODS

Left atrial (LA) sites were sequentially targeted as follows: (1) coronary sinus and vein of Marshall (CS-VOM) musculature; (2) PVI; and (3) anatomical isthmuses (mitral, roof, and cavotricuspid isthmus [CTI]). The primary endpoint was 12-month freedom from AF/atrial tachycardia (AT).

RESULTS

Seventy-five consecutive patients were included (age 61 ± 9 years; 10 women; AF duration 9 ± 11 months; mean LA volume 197 ± 43 mL). VOM ethanol infusion was completed in 69 patients (92%). The full Marshall-PLAN lesion set (VOM, PVI, mitral, roof, and CTI with block) was successfully completed in 68 patients (91%). At 12 months, 54 of 75 patients (72%) were free from AF/AT after a single procedure (no antiarrhythmic drugs) in the overall cohort. In the subset of patients with a complete Marshall-PLAN lesion set (n = 68), the single procedure success rate was 79%. After 1 or 2 procedures, 67 of 75 patients (89%) remained free from AF/AT (no antiarrhythmic drugs). After 1 or 2 procedures, VOM ethanol infusion was complete in 72 of 75 patients (96%).

CONCLUSION

A novel ablation strategy that systematically targets anatomical atrial structures (VOM ethanol infusion, PVI, and prespecified linear lesions) is feasible, safe, and associated with a high rate of freedom from arrhythmia recurrence at 12 months in patients with persistent AF.