Ethanol Infusion Research Articles

Pulmonary Vein Isolation With Optimized Linear Ablation vs Pulmonary Vein Isolation Alone for Persistent AF

Success rates of pulmonary vein isolation (PVI) are modest for persistent atrial fibrillation (AF). Additional linear ablation beyond PVI has not been proved superior to PVI alone in randomized trials. Ethanol infusion of the vein of Marshall (EIVOM) facilitates ablation at the mitral isthmus and may lead to improved effectiveness of a linear ablation strategy. To determine whether linear ablation with radiofrequency energy combined with EIVOM added to PVI improves sinus rhythm maintenance compared with PVI alone in patients with persistent AF. The PROMPT-AF trial is an investigator-initiated, multicenter, open-label, randomized trial involving 12 tertiary hospitals in China. A total of 498 patients aged 18 to 80 years, with AF persisting for more than 3 months, undergoing first-time AF ablation, were enrolled and randomized from August 27, 2021, to July 16, 2023. Patients were randomized to undergo PVI alone or PVI plus EIVOM and linear ablation (intervention). The latter group first underwent EIVOM, followed by PVI and linear ablation of the left atrial roof, mitral isthmus, and cavotricuspid isthmus. The primary end point was freedom from any documented atrial arrhythmias lasting more than 30 seconds, without the use of antiarrhythmic drugs within 12 months. Secondary outcomes included freedom from atrial arrhythmia recurrence, AF, atrial arrhythmia recurrence after multiple procedures, and documented atrial tachycardia or atrial flutter with or without antiarrhythmic drugs; AF burden; and improvement in quality of life. Patients were monitored with wearable single-lead electrocardiographic (ECG) patches, worn for 24 hours a week, supplemented by symptom-triggered ECGs and Holter monitoring. Among 498 randomized patients, 495 (99.4%) were included in the primary analysis (mean age, 61.1 years [SD, 9.7] years, 361 male [72.9%]). After 12 months, 174 of 246 patients (70.7%) assigned to undergo PVI plus EIVOM and linear ablation and 153 of 249 patients (61.5%) assigned to undergo PVI alone remained free from atrial arrhythmias without taking antiarrhythmic drugs (hazard ratio, 0.73; 95% CI, 0.54-0.99, P = .045). The intervention effect was consistent across all prespecified subgroups. The comparison of secondary outcomes did not demonstrate significant results. Among patients with persistent AF, linear ablation combined with EIVOM in addition to PVI significantly improved freedom from atrial arrhythmias within 12 months compared with PVI alone. ClinicalTrials.gov Identifier: NCT04497376.

Abstract 4135869: Local Ethanol Infusion after Pulsed Field Ablation Enhances Acute Efficacy of In Vivo Ventricular Electroporation

Background: Pulsed field ablation (PFA) has emerged as an innovative technology for treating cardiac arrhythmias. PFA increases cell permeability, which can lead to apoptosis. Greater PFA energy may be necessary to ablate ventricular myocardium for ventricular tachycardia circuits, but this carries risks of side effects such as gaseous formation (microbubbles) and hemolysis. Ethanol (EtOH) infusion has been used to ablate pathologic myocardial tissues in hypertrophic cardiomyopathy and for refractory arrhythmias. Hypothesis: We hypothesize that PFA in the ventricle can increase EtOH uptake through PFA-generated pores, thereby enhancing ablation efficacy, even at low powers, by utilizing the cell permeability effects of PFA. Aim: The aim of this study is to investigate the effect of local EtOH infusion after PFA on lesion size in porcine ventricles. Methods: The ventricles of five porcine subjects were ablated in vivo with a PFA low power setting (750 V, at 20 μs for 50 pulses separated by 200 ms) using a focal bipolar irrigated ablation catheter and BTX 830 electroporation generator (Harvard Apparatus). After PFA was performed, 2 ml of 90 % EtOH vs. saline (control) was infused through the catheter tip to the site of ablation. We compared the electrograms voltage amplitude reduction before and after PFA, and the ablation lesion characteristics. Results: A total of 10 lesions in the control group and 9 lesions in the EtOH group were analyzed. For the controls, the voltage after PFA was not reduced. In contrast, for the EtOH group, the voltage after PFA was significantly reduced ( Figure 1A ). On gross pathology, there were significant differences in ablation lesion depths and volumes between the 2 lesion sets ( Figure 1A-B ). Conclusion: Local EtOH infusion after ventricular PFA enhanced acute efficacy of electroporation. Concurrent PFA with local EtOH infusion has the potential to improve efficacy without requiring higher energy parameters, thereby reducing PFA risks. Future studies on chronic efficacy are warranted.

Abstract 4114716: Concurrent Ethanol Infusion with Pulsed Field Ablation Augments Electroporation of Porcine Atria

Background: Pulsed field ablation (PFA) is a promising modality for treatment of cardiac arrhythmias. PFA increases cell permeability, thereby promoting cell apoptosis. Although greater PFA energy may produce larger lesions, it also carries risks of side effects such as arcing, hemolysis, and microbubbles. Chemical ablation using ethanol (EtOH), such as with injection of the Vein of Marshall, has been used to treat atrial myocardium for refractory atrial arrhythmias. Hypothesis: We hypothesize that PFA in the atria can increase EtOH uptake through PFA-generated pores, thereby augmenting ablation efficacy by utilizing the cell permeability effects of PFA. Aim: The aim of this study is to investigate the effects of local EtOH infusion after PFA on lesion size in porcine atria. Methods: The atria of five porcine subjects were ablated in vivo with low PFA power settings (250V, at 20μs for 50 pulses separated by 200 ms) using a focal bipolar irrigated ablation catheter and BTX 830 electroporation generator (Harvard Apparatus). After PFA, 2 ml of 90 % EtOH vs. saline (control) was infused through the catheter tip to the site of ablation. We compared electrogram voltage amplitude reduction and ablation lesion parameters before and after PFA. Results: A total of 14 control lesions and 14 EtOH lesions were analyzed. There was significant difference in voltage reduction between two groups ( Figure 1A-B ). On gross pathology, there were significant differences in ablation lesion maximum surface diameter, lesion depth, and volume between the 2 lesion sets ( Figure 1C ). Conclusion: Concurrent EtOH infusion after PFA enhanced acute efficacy of electroporation in porcine atria. Adjuvant therapy has the potential to improve efficacy without requiring higher energy parameters, thereby reducing PFA risks. Further studies to assess chronic efficacy are warranted.

Left Atrial Structure and Function Following Ethanol Infusion into Vein of Marshall (MR-SHALL Study).

Ethanol infusion into the vein of Marshall (EI-VOM) is an adjunctive therapy to pulmonary vein isolation (PVI), which improves the efficacy of persistent atrial fibrillation (AF) ablation procedures. It is unknown how EI-VOM scar formation impacts left atrium (LA) structure and function. To characterize scar formation after EI-VOM, and its impact on LA function, by cardiac magnetic resonance (CMR). Consecutive patients referred for persistent AF ablation, or any repeat procedure, were included. Ablation strategy included PVI, EI-VOM and linear lesions when deemed necessary. LA was assessed by late gadolinium enhancement (LGE) CMR at baseline and 3-month follow-up. CMR was post-processed off-line with dedicated software. The LA was regionalized into 17 segments, and global and regional scarring were calculated. Strain parameters were analyzed-including LA reservoir, conduit, and booster strain; LA ejection fraction; and LA passive and active emptying function. Follow-up LGE-CMR reconstruction was coregistered with the voltage map, ablation RF points, and fluoroscopy to compare the scar location with the VOM trajectory. This study included 21 patients (65 ± 8 years; 76% men; 57% ablation of persistent AF). After EI-VOM, 95% of patients presented new low-voltage areas, all of whom exhibited new LGE-CMR scarring at follow-up. Voltage map and LGE-CMR coregistration showed comparable scar areas (p = 0.287). LGE-CMR scarring frequently involved the whole VOM trajectory, predominantly affecting the LA ridge, mitral isthmus, and left posterior wall. LA volume was significantly reduced after ablation, without significant changes in LA functional parameters. EI-VOM causes permanent scarring at 3-month follow-up, with no adverse impact on CMR LA functional parameters.

Anatomical Treatment Strategies for Persistent Atrial Fibrillation with Ethanol Infusion within the Vein of Marshall—Current Challenges and Future Directions

Currently, pulmonary vein isolation (PVI) is the gold standard in catheter ablation for atrial fibrillation (AF). However, PVI alone may be insufficient in the management of persistent AF, and complementary methods are being explored. One such method takes an anatomical approach—improving both its success rate and lesion durability may lead to improved treatment outcomes. An additional approach complementary to the anatomical one is also attracting attention, one that focuses on epicardial conduction. This involves ethanol ablation of the vein of Marshall (VOM) and can be very effective in blocking epicardial conduction related to Marshall structure; it is becoming incorporated into standard treatment. However, the pitfall of this “Marshall-PLAN”, a method that combines an anatomical approach with ethanol infusion within the VOM (Et-VOM), is that Et-VOM and other line creations are not always successfully completed. This has led to cases of AF and/or atrial tachycardia (AT) recurrence even after completing this lesion set. Investigating effective adjunctive methods will enable us to complete the lesion set with the aim to lower the rates of recurrence of AF and/or AT in the future.

Ethanol infusion into the vein of Marshall reduced atrial tachyarrhythmia recurrence during catheter ablation: A systematic review and meta-analysis

Ethanol infusion into the vein of Marshall (EIVoM) may increase mitral isthmus bidirectional block (MIBB) and cause local autonomic denervation that may improve outcome. This meta-analysis aimed to investigate whether the addition of EIVoM to atrial fibrillation (AF) ablation led to a better outcome. Systematic literature search was performed using PubMed, Scopus, ScienceDirect, and Europe PMC for studies that compared the addition of EIVoM during AF ablation with radiofrequency ablation. The primary outcome was atrial tachyarrhythmia (ATa) recurrence, defined as AF/atrial flutter/atrial tachycardia after the blanking period. There were 2821 patients from 11 studies, and EIVoM was successful in 77% (95% confidence interval [CI] 62%-92%). ATa recurrence was 27% (95% CI 20%-34%) in the EIVoM group and 42% (95% CI 33%-51%) in ablation-only group. EIVoM reduced ATa recurrence (odds ratio [OR] 0.52; 95% CI 0.36-0.76; P < .001; I2 = 76.92). The rate of MIBB was 85% (95% CI 77%-94%) in the EIVoM group and 73% (95% CI 61%-85%) in the ablation-only group, which was significantly higher (OR 3.87; 95% CI 1.46-10.28; P < .001; I2 = 83.68). The mitral isthmus reconnection rate (OR 0.44; 95% CI 0.15-1.29; P = .14; I2 = 63.6) and repeat procedure rate (OR 0.76; 95% CI 0.53-1.08; P = .12; I2 = 48) were similar; however, a leave-one-out sensitivity analysis showed P < .05 for both. The benefits of EIVoM were not affected by age, left atrial diameter, and left ventricular ejection fraction (P > .05). Age (P = .029) and left atrial diameter (P = .042) were inversely associated with EIVoM benefits in terms of repeat ablation and mitral isthmus reconnection (age; P = .003). The addition of EIVoM to ablation increased MIBB and reduced ATa recurrence.

Catheter ablation for atrial fibrillation: indications and future perspective.

Recent advances in techniques, technologies and proven superiority over anti-arrhythmic drugs have made catheter ablation the cornerstone of management for atrial fibrillation (AF), which has shown a steady increase in prevalence in the ageing population worldwide. The aim of therapeutic interventions is to achieve stable sinus rhythm that would improve the quality of life and reduce the risk of AF-associated complications. Pulmonary veins (PVs) were first described as the source of initiation of ectopic triggers driving AF, which led to the establishment of PV isolation (PVI) as the most widely practiced procedure to treat AF. Antral PVI is still recognized as the stand-alone ablation strategy for newly diagnosed paroxysmal AF (PAF). However, in non-PAF patients, PVI seems to be inadequate and several adjunctive strategies, including ablation of left atrial posterior wall and non-PV triggers, AF mapping and ablation of rotors and drivers, ethanol infusion of vein of Marshall and renal denervation, etc. have been reported with mixed results. Recent trials have also documented the benefits of early rhythm control in preventing cardiovascular events in addition to slowing the progression of PAF to more persistent forms. Similarly, very late relapse of the arrhythmia after successful PVI has drawn attention to the critical role of non-PV triggers and highlighted their relevance as potential ablation targets during repeat procedures. Ablation technology is also under constant evolution with the introduction of non-thermal energy sources and new tools to create durable lesions. This review summarizes the indications, advancements, and future perspective of AF ablation.

Mechanisms of Mitral Isthmus Reconnection After Ablation With and Without Vein of Marshall Ethanol Infusion

BackgroundReconnection of the mitral isthmus (MI) is common after radiofrequency ablation (RFA). Vein of Marshall ethanol infusion (VOMEI) expedites MI ablation, but long-term results are unclear. ObjectivesThis study sought to determine anatomic substrates of failed MI ablation, with and without VOMEI. MethodsConsecutive VOMEI procedures were included (n = 231; of which 140 were de novo ablations and 91 were prior RFA failures (rescue VOMEI). MI conduction mechanisms were studied with vein of Marshall (VOM) electrograms obtained with a 2-F octapolar catheter, mapping, and differential pacing. ResultsIn rescue VOMEI, intact VOM electrograms showed epicardial connections, epi-endocardial dissociation, and VOM conduction in pseudo-MI block. After VOMEI, after a follow-up of 725 ± 455 days, 78 patients (33.7%) experienced recurrence. Of those, 36 (46%) had evidence of MI reconnection and 42 had other mechanisms. Of the 36 patients with MI reconnection, endocardial radiofrequency (RF) at the annular MI restored block in 16 (45%), and coronary sinus (CS) RF was required in 20 (55%). Post-VOMEI recurrence mechanisms included CS connection–dependent arrhythmias: CS-mediated perimitral flutter, CS–to–left atrium (LA) and CS ostial re-entry, and CS focal activity. Intraprocedural factors associated with MI reconnection included volume of ethanol delivered ≥4 mL (OR: 0.74; P = NS), CS ablation at VOMEI (OR: 4.05; P = 0.003), and age (OR: 1.06; P = 0.011). ConclusionsMI reconnections after RFA are due to epicardial connections from VOM. Recurrences after VOMEI are due to incomplete annular MI RFA and CS arrhythmogenesis including CS-mediated perimitral flutter, CS-to-LA re-entry and CS focal activity. Adding complete CS disconnection to VOMEI may prevent recurrences.

Activation patterns and electrophysiologic characteristics of Marshall bundle–related left atrial tachycardias after atrial fibrillation ablation

BackgroundEpicardial Marshall bundles (MBs) are frequently used in left atrial tachycardias (LATs) after atrial fibrillation (AF) ablation with pulmonary vein isolation and substrate modification. ObjectiveThis study sought to classify different activation patterns of MB-mediated LATs and the corresponding electrophysiologic characteristics. MethodsFrom 2019 to 2021, 28 cases of atrial tachycardias after AF ablation were diagnosed as MB-mediated LATs by ultrahigh-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. ResultsThree activation patterns were identified with a critical isthmus through the MB: perimitral macroreentry (perimitral LAT; n = 20 [71.4%]); left atrial appendage–related reentry (n = 5 [17.9%]); and left pulmonary vein–related reentry (n = 3 [10.7%]). In 18 patients, a characteristic triple potential observed along the previously endocardial left atrial 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 atrial tachycardia termination in 20 of 28 patients. ConclusionDifferent types of MB-mediated LATs after AF ablation could be identified by ultrahigh-density mapping. Ethanol infusion within the VOM was effective in eliminating these tachycardias.

Vein of Marshall ethanol infusion for recurrent atrial fibrillation in patients with durably isolated pulmonary veins.

Vein of Marshall (VoM) ethanol ablation has a proven benefit in patients with persistent atrial fibrillation (AF) undergoing index procedure; however, its role in repeat ablation is unknown. We sought to evaluate the benefit of empiric VoM ethanol ablation in addition to posterior wall isolation (PWI) during the repeat procedure in patients with durable pulmonary vein (PV) isolation from prior ablation. Twenty-three patients (age 67.1 + / - 7.4, 74% males) who received empiric VoM ethanol infusion in addition to PWI were matched for age, gender, ejection fraction, and left atrial size with forty-six patients receiving empiric PWI alone. All patients in the study group underwent additional ablation on mitral isthmus to complete the lateral mitral isthmus line. Additional ablation was based on program and trigger stimulation. Primary outcome was freedom from AF after a blanking period of 3months by qualification of symptoms, EKG, wearable, or implantable monitor or device. The study group had a higher average BMI (35.07 + / - 8.98 vs. 30.85 + / - 5.65, p = 0.033) and rate of persistent AF (83.0% vs. 54.3%, p = 0.029) versus the control. The 1-year AF-free survival for the study and control groups was 20 (86.96%) and 28 (60.1%) patients (p = 0.027). Cox proportional hazard regression analysis showed a significant reduction in AF recurrence in the study group (HR 0.25, 95% CI 0.073-0.843, p = 0.026). Among patients undergoing repeat catheter ablation for recurrent AF with durably isolated PVs, the addition of VoM ethanol infusion increased the likelihood of remaining free from AF at 12months.

Quantitative investigation of acute lesions created by ethanol infusion into the vein of Marshall

BackgroundEthanol infusion into the vein of Marshall (EIVOM) has been performed as an adjunctive atrial fibrillation therapy. However, the time course change, quantitative lesion investigation, and effects on epicardial fat pads and fractionated atrial electrograms created by EIVOM have never been investigated. ObjectiveThis study aimed to perform a quantitative analysis of lesions created by EIVOM. MethodsWe created voltage maps using a 3-dimensional mapping system immediately before and 30 minutes and 60 minutes after performing EIVOM to study the time course change in the lesions. We compared differences in the average contact force value required for successful conduction block in the Marshall vein area of patients with and without EIVOM. We also investigated effects of EIVOM on the area of complex fractionated atrial electrograms before and after EIVOM. We measured the total epicardial fat pad volume before and after EIVOM by computed tomography. ResultsVoltage was significantly reduced after EIVOM, and there were significant differences in voltage reduction between the control status and 30 minutes and 60 minutes after EIVOM (P < .05). The average contact force value was significantly lower with vs without EIVOM (P < .05). The total epicardial fat volume and complex fractionated atrial electrogram area also significantly decreased after EIVOM (P < .05). ConclusionEIVOM provided significant therapeutic effects on the left atrial tissue perpetuating atrial fibrillation, which was demonstrated by a quantitative analysis.

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

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. 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. 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). 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.

Exploring new frontiers: a rare case of catheter ablation for persistent atrial fibrillation in a patient with cor triatriatum sinister guided by intracardiac echocardiography

BackgroundCor triatriatum sinister (CTS) is an uncommon congenital cardiac anomaly. Atrial fibrillation (AF) is commonly the initial symptom in patients with CTS, occurring in approximately 32% of the cases. The complexity of performing AF catheter ablation, particularly in cases with persistent AF, increases in patients with CTS due to its unique structural challenges.Case presentationWe report the treatment course of a 60-year-old male patient diagnosed with CTS, who underwent catheter ablation of drug-refractory, persistent AF. The complex anatomical structure of the condition made catheter ablation of AF challenging. To navigate these challenges, we performed comprehensive assessments using transthoracic echocardiography and transesophageal echocardiography, along with cardiac computed tomography angiography, prior to treatment initiation. The intricate anatomy of CTS was further clarified during the procedure via intracardiac echocardiography (ICE). Additionally, the complexity of catheter manipulation was further reduced with the aid of the VIZIGO sheath and the vein of Marshall ethanol infusion to achieve effective mitral isthmus blockage, thereby circumventing the impact of the CTS membrane.ConclusionsThis case underscores the complexity and potential of advanced ablation techniques in managing cardiac arrhythmias associated with unusual cardiac anatomies. During the procedure, ICE facilitated detailed modeling of the left atrium, including the membranous structure and its openings, thus providing a clearer understanding of CTS. It is noteworthy that the membrane within the CTS may serve as a potential substrate for arrhythmias, which warrants further validation through larger sample studies.

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.

The Evaluation of the Phytochemical Profiles and Antioxidant and α-Glucosidase Inhibitory Activities of Four Herbal Teas Originating from China: A Comparative Analysis of Aqueous and Ethanol Infusions.

Recent research has demonstrated the positive impact of herbal tea consumption on postprandial blood glucose regulation. This study conducts a comparative analysis of aqueous and ethanol extractions on four herbal teas (Mallotus, Cyclocarya, Rubus, and Vine) to assess their phytochemical profiles and functional attributes. Phytochemical contents, antioxidant activities, α-glucosidase inhibitory activities, and chemical compositions are investigated via colorimetric analyses and UPLC-Q-Orbitrap HRMS/MS, respectively. Results indicate that Vine, among the teas studied, exhibits the most pronounced glucose-regulating effects under both extraction methods. While ethanol extractions yield higher phytochemical content overall, the compositions vary. Conversely, aqueous extracts demonstrate unexpectedly potent antioxidant activities and comparable α-glucosidase inhibitory activities to ethanol extracts. Phytochemical contents correlate positively with antioxidant activities and α-glucosidase inhibitory activities. However, antioxidant activities exhibit a weak positive correlation with α-glucosidase inhibitory activities. These findings provide evidence that aqueous extracts from herbal teas contain valuable phytochemical compositions beneficial for antioxidants and individuals with hyperglycemia, suggesting their potential as functional ingredients to enhance the nutritional value of herbal food products.

A proposed index of myocardial staining for vein of marshall ethanol infusion

Abstract 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. Purpose 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 our Institution 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 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). Conclusion In our study cohort, optimal MSI predicts MI block and facilitates its achievement with endocardial ablation only.Myocardial stainingSpline plots

Low voltage area in the left atrial anterior wall predict Marshall-PLAN failure in patients with persistent atrial fibrillation

Abstract Background The most appropriate ablation strategy for persistent atrial fibrillation (PeAF) has not yet been determined. However, ethanol infusion of the vein of Marshall (VOM) combined with a linear set of ablation lesions (namely the Marshall-PLAN) has yielded encouraging results (1). Purpose Our study aimed at analyzing the relationship between low voltage areas (LVA) and arrhythmias recurrences in a PsAF population treated with the Marshall-PLAN. Methods we conducted a retrospective study on consecutive patients undergoing first catheter ablation (CA) for PsAF between 2021 and 2022 at our center. Pulmonary vein isolation (PVI), mitral isthmus ablation (VOM ethanol infusion, endocardial ablation and epicardial ablation in the great cardiac vein), left atrial (LA) roofline and cavo-tricuspid isthmus ablation were carried out in all the patients. Bidirectional block was validated for all the linear lesions as well as for PVI. Pre-ablation LA electroanatomic maps were built with CARTOv3 system and the PentaRay mapping catheter (minimum 3000 points). LVA were identified as areas &amp;gt;1cm2 (containing ≥3 neighboring points with ≤10mm distance) with bipolar voltage &amp;lt;0.5mV in SR and &amp;lt;0.24 mV in AF (2). All patients were followed for at least 12 months. Results Overall, 93 patients (69±7years, 30% female) with PsAF were included. Their left-ventricle ejection fraction and left atrial volume indexed for body surface area (LAVI) were 57% and 92±20 ml/m2. LA maps demonstrated at least one LVA in 70 subjects (75.3%). The mean relative surface of LA in which a LVA was evidenced was 8±14%. LVA were found within the anterior LA wall in 49 patients (53%), in the posterior wall in 33 patients (35.5%), in the inferior wall in 22 patients (24%), in the lateral wall in 14 patients (15.1%) and in the pulmonary vein region in 44 patients (47.3%). After 19±6 months of follow-up, 28 (30%) patients had AF recurrence. At Cox regression analysis (including LVA burden and LAVI dimensions), LVA localized within the anterior LA wall were predictive of arrhythmia recurrences (hazard ratio [HR] 2.0 [95% CI, 1.1–4.7], P=0.04). Kaplan-Meier estimates of survival free from recurrences at 20 months were 51% and 88% in patients with and without LVAs in the anterior LA wall (Log-rank 0.006). Conclusions The Marshall-PLAN led to a global AF-free survival of 70% after 19±6 months in our cohort of patients with PsAF. Importantly however, the data show that the subset of patients with LVA in the anterior LA wall (i.e., the LA region not targeted by the pre-specified ablation set here evaluated) have a 55%-only AF-free survival while that of patients without LVA in the anterior LA wall was of 88%. As a result, our study supports the relevance of atrial substrate assessment and the possibility of CA strategy optimization in the subset of patients with PsAF and LVA in the anterior LA wall (3).

Atrial voltage analysis following vein of marshall alcohol infusion predicts mitral line block

Abstract Background The vein of Marshall (VOM) is a promising therapeutic target for the atrial fibrillation (AF) treatment, fitting perfectly with the "Coumel triangle" as it contains triggers of focal activities and stable reentries, autonomic parasympathetic and sympathetic connection and it represents substrate for perimitral flutters. Lateral mitral line (ML) represents a fundamental part of the anatomical ablation setup for the treatment of AF but its bidirectional block is very difficult to achieve by endocardial ablations. Ethanol infusion into the VoM (VOM-EI) has demonstrated high effectiveness in facilitating ML block. Newly-formed bipolar lesion after VOM-EI is considered an index of effectiveness of the alcoholization procedure. Voltage analysis assessment after VOM-EI in predicting ML block is poorly investigated. Purpose To compare unipolar and bipolar low-voltage areas (LVAs) along VOM trajectory after VOM-EI, and their role in predicting ML block. Methods We enrolled 59 patients undergoing catheter ablation for persistent AF or mitral isthmus dependent atrial flutter. We performed first a high-density voltage map of the left atrium. After VOM-EI, a LA remap was performed. The area width difference was obtained and defined as ∆LVA (see Figure 1). Normal Bipolar voltage cutoffs were 0.50 mV in case of sinus rhythm or 0.29 mV in case of AF. Unipolar cutoffs were respectively 2.7 mV in sinus rhythm and 1.1 mV in AF. The anatomical lesions set, after VOM-EI, included wide antral PVI, linear lesion for dome and ML isthmus following the newly-formed lesion after the VOM-EI. Systematic lines block validation was performed. ML block was defined after coronary sinus electrograms sequence inversion (septal-to-lateral) during left atrial appendage pacing. In case of residual conduction gaps, RF applications into the coronary sinus-great cardiac vein were done to target residual epicardial gaps. Ablation time to obtain ML block (AblTime) was obtained. Results In our group, 56/59 patients (94.5%) achieved mitral isthmus block. Bipolar and unipolar low voltage areas after VOM-EI were 9.9 ± 6.9 cm2 and 12.2 ± 5.9 cm2 respectively. Bipolar ∆LVAs were significantly lower compared with unipolar ∆LVA (8.2 ± 6.5 cm2 vs 9.4 ± 6.0 cm2; p= 0.03). A strong linear correlation between AblTime and bipolar ∆LVA (R: 0.76) and a significant correlation between AblTime and unipolar ∆LVA (R: 0.6) were found (Figure 2). Patients that required coronary sinus applications to reach ML block (13/59, 22%), presented lower ∆LVAs at logistic regression both at bipolar (p&amp;lt;0.01) and unipolar (p=0.03) analysis. Conclusions Unipolar and bipolar voltage analysis along the mitral isthmus trajectory predicts ML block achievement, with VOM-EI inducing wider unipolar LVAs than bipolar LVAs. Furthermore, wider unipolar and bipolar LVAs post VOM-EI are linked to a shorter AblTime and an increased probability of avoiding the need to target epicardial gaps via the CS musculature.LVA along VOM territory after VOM EI∆LVAs linear correlation with AblTime

A novel approach to invisible vein of Marshall: extending the utility of ethanol infusion into the vein of Marshall

Abstract Background The utility of ethanol infusion into the vein of Marshall (EIVOM) is limited in patients without a visible vein of Marshall (VOM). Methods Our study included of 232 patients with atrial fibrillation undergoing MI ablation. We initially performed coronary sinus venography using a balloon catheter in all patients to assess VOM characteristics. EIVOM was attempt in those with adequately visible VOMs. In cases where the VOM was not visible, we utilized a guide-wire to locate its entrance, using the intravenous valve as a landmark. Results Venography initially identified the VOM in 140 of 232 patients (60%) (visible VOM group). Within this group, 68 patients (29%) did not require balloon inflation for VOM visualization, while 72 patients (31%), visibility was achieved through balloon inflation. In the remaining 92 patients (39%), the VOM remained invisible even after balloon inflation. Nevertheless, in 13 of these cases, the VOM was successfully located using a landmark technique (invisible VOM group). EIVOM was fully achieved in 96% (147 of 153 patients). Additionally, full MI line blocks were achieved in 91% of (A) the visible VOM group (122 of 134 patients), 92% of (B) the invisible VOM group (12 of 13 patients), and 81% in (C) the EIVOM (-) group (69 of 85 patients) (A vs. B, p = 0.88; A vs. C, p &amp;lt; 0.05; B vs. C, p = 0.32). Conclusion A novel approach to locating invisible VOM extends the clinical utility of EIVOM and potentially improves success rate of MI ablation.Guide-wire insertion into invisible VOM

Acute impact of vein of marshall ethanol infusion combined with anatomical ablation validated by pacing in redo ablation of persistent atrial fibrillation

Abstract Background Catheter ablation with radiofrequency in persistent atrial fibrillation (PeAF) has limited success and a significant proportion of patients requires redo ablation. Several trials showed that addition of vein of Marshall ethanol infusion (Vom-EI) to catheter ablation, compared with catheter ablation alone, increases the possibilities of remaining free of AF. No data are available about the effect on VoM-EI in Pe-AF patients that undergo a redo ablation. Purpose We evaluated acute impact on lesion formation post-VoM-EI and the mitral line block validation after a methodical approach including VoM-EI and check of pulmonary vein isolation (PVI), roof-line, mitral line (ML) and cavo-tricuspid isthmus line in a population of PeAF patients undergone redo ablation. We aimed also the results of a short follow-up. Methods Consecutive patients undergoing redo ablation for PeAF were enrolled. All patients underwent check of PVI, left atrium (LA) roofline and cavotricuspid isthmus line and, if necessary, ablation was completed. In all patients, after a detailed electroanatomical map of the LA (filter at 0.05-0.5 mV if the patient was in sinus rhythm or 0.05-0.3 mV in the case of AF), we proceeded with the VoM-ETHO. LA map was thus repeated to assess the extension of the newly-formed low voltage area (LVA). According to the newly-formed LVAs, the validation of mitral line was obtained by the evidence of bidirectional block. In presence of conduction through the mitral line also after endocardial revision, we proceeded to mapping and ablating in the CS epicardial gaps in the "anchored wall" or in the "free-wall"of the great cardiac vein (GCV). Results Twenty consecutive patients (64±8 years and 65% male) undergone redo ablation for AF with VoM-EI were included in this study. All patients underwent PVI in the previous procedure but only in 11 roof line has been performed. In twenty patients (52%) reconnection of PV was observed (12/20 in right superior pulmonary vein). In 4/11 roof line was not complete. The medium value of basal LA-LVAs was 3.38土5.27 cmq and the newly-formed LVAs after the VoM-EI procedure was 9.21土5.63 cmq. All patients achieved bidirectional block validated across ML: in 8/20 after epicardial gaps ablations into the anchored wall of GCV and in 6/20 after epicardial gaps ablation in the free wall of GCV. The ML procedural time was 18.82土12.79 minutes. The number of radiofrequency irrigation was 20.11土10.56. No major complications occurred. Five patients had VOM dissection without consequences. During a short follow-up period (6土5 months), only one patient had AF recurrences after the blanking period of one month. Conclusions VoM ethanol ablation added to PVI and linear lesions in the context of a methodical and anatomical approach during redo ablation of PeAF patients seems to have promising results and to be safe. Longer follow-up is needed to understand the role of this technique in redo ablation.