MARSHALL bundles elimination, Pulmonary veins isolation and Lines completion for ANatomical ablation of persistent atrial fibrillation: MARSHALL-PLAN case series

Marshall-Plan Ablation Strategy Versus Pulmonary Vein Isolation in Persistent AF: A Randomized Controlled Trial

BACKGROUND

Beyond pulmonary vein (PV) isolation, the optimal ablation strategy for persistent atrial fibrillation (AF) remains poorly defined. The purpose of this study was to compare 2 ablation strategies in the treatment of patients with persistent AF: a comprehensive ablation strategy based on anatomic considerations versus PV isolation alone.

METHODS

The Marshall-Plan trial is a prospective, randomized, parallel-group, controlled clinical trial of superiority conducted at the Bordeaux University Hospital. Consecutive patients with symptomatic, documented persistent AF were included and randomized into 2 arms: Marshall-Plan consisting of PV isolation with additional ablation including vein of Marshall ethanol infusion, and lines of block at the mitral, dome, and cavotricuspid isthmuses versus PV isolation alone. The main outcome was the 1-year freedom from any arrhythmia (atrial fibrillation/atrial tachycardia >30 seconds) after a single ablation procedure with or without any antiarrhythmic medication at 12 months.

RESULTS

A total of 120 patients were included (age 65±8 years; 21 women). Two patients were excluded from analysis. All PVs were successfully isolated in both groups. In the Marshall-Plan group, vein of Marshall ethanol infusion was completed in 57 (97%) patients. Conduction block across linear lesions was obtained in 93%, 92%, and 93% of the mitral, dome, and cavotricuspid isthmuses, respectively. The full lesion set was successfully completed in 52 (88%) patients in the Marshall-Plan group and 59 (100%) patients in the PV isolation group. At 12 months, freedom from recurrence of atrial arrhythmia >30 seconds after 1 ablation procedure, with or without antiarrhythmic medication, had occurred in 51 of the 59 (86.4%) patients assigned to the Marshall-Plan approach, and 39 of the 59 (66.1%) patients assigned to PV isolation only (P=0.012).

CONCLUSIONS

In this prospective randomized controlled trial, the Marshall-Plan strategy was significantly superior to a PV isolation strategy at 12 months.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04206982.

Left atrial posterior volume and posterior-anterior volume ratio as predictive factors for atrial fibrillation recurrence: Insights from regional atrial remodeling

BACKGROUND

Atrial fibrillation (AF) recurrence after catheter ablation poses a persistent clinical challenge. This study investigates the predictive value of left atrial posterior (LA-P) volume and the posterior-anterior volume ratio (PAVR) using computed tomography angiography (CTA).

OBJECTIVE

This study aimed to assess the predictive significance of LA-P volume and PAVR for AF recurrence using CTA in patients undergoing catheter ablation.

METHODS

A retrospective cohort of 365 patients who underwent AF ablation was analyzed. CTA assessed LA-P volume, left atrial anterior volume, left atrial appendage volume, and PAVR. AF recurrence was the primary outcome. Kaplan-Meier survival analysis, multivariate Cox proportional hazards regression, and restricted cubic spline analyses evaluated associations between volumetric indices and AF recurrence.

RESULTS

LA-P volume was positively associated with AF recurrence in a linear pattern (P < .001). Patients in the highest LA-P volume quartile had significantly higher recurrence rates (log-rank P < .001), with a multivariate adjusted hazard ratio (aHR) of 2.90 (95% confidence interval [CI] 1.49-5.66; P for trend = .005) compared with the lowest quartile. Per standard deviation increment, LA-P volume was associated with a 42% increased recurrence risk (aHR 1.42; 95% CI 1.16-1.72). PAVR was independently linked to recurrence (aHR per standard deviation increment 1.35; 95% CI 1.15-1.58; P < .001).

CONCLUSION

LA-P volume and PAVR are significant predictors of AF recurrence, underscoring the importance of regional atrial volumetric assessments to refine risk stratification and inform personalized treatment strategies for patients undergoing AF ablation.

First-Line Marshall Plan Approach in Persistent Atrial Fibrillation: A Prospective Single-Center Cohort Study

BACKGROUND

Different ablation strategies have been developed for persistent atrial fibrillation (PeAF), but early management is still controversial. In the clinical setting of PeAF, the safety and efficacy of early Marshall plan have not yet been fully studied.

OBJECTIVES

Our prospective cohort study sought to: (1) assess the safety and feasibility of the thermal Marshall plan (MPA) approach as a first-line therapy in PeAF patients; (2) evaluate its long-term sinus rhythm maintenance efficacy; (3) identify the long-term predictive factors of AF recurrence in PeAF patients after MPA approach.

METHODS AND RESULTS

Between January 2020 and December 2023, 118 PeAF patients were selected for first intent Marshall plan ablation (MPA). Marshall vein failure occurred in 9/118 patients (7.6%). Accordingly, 109 patients who underwent MPA as first-line therapy were included. After the blanking period of 3 months, 62/109 patients were in sinus rhythm (SR) (57%), 33/109 were in AF (30.2%), 8/109 were in left atrial flutter (AFL) (7.3%), and six were in right AFL (5.5%). Re-ablation was performed in 4/33 patients (12.1%) and cardioversion in 29/33 (87.9%) for patients in AF at 3 months after healing. All patients in AFL at 3 months were re-ablated and all recovered SR. At 12 months postablation, two patients were lost to follow-up (1.8%), 94/107 (87.8%) were in SR and 13/107 had AF recurrence (12.2%). At 21 ± 11 months postablation, 81/107 (75.7%) were in SR at the last control, and 26/107 (24.3%) had AF recurrence. The ablation procedure ratio was 1.17 (109 primo ablation, 18 re-ablation). The only predictive factors of late AF recurrence after first-line PeAF MPA were both left atrial dilatation and low left ventricular ejection fraction (LVEF).

CONCLUSIONS

This real-life prospective cohort study showed that de novo MPA in PeAF is feasible, relatively safe, and associated with a high rate of freedom from arrhythmia recurrence during long-term follow-up. The percentage of patients remaining in SR during long-term follow-up was close to 76%. The only predictive MPA failure factors were both left atrial dilatation and low LVEF.

Atypical Atrial Flutter: Electrophysiological Characterization and Effective Catheter Ablation

Atrial flutter (AFL), defined as macro-re-entrant atrial tachycardia, is associated with debilitating symptoms, stroke, heart failure, and increased mortality. AFL is classified into typical, or cavotricuspid isthmus (CTI)-dependent, and atypical, or non-CTI-dependent. Atypical AFL is a heterogenous group of re-entrant atrial tachycardias that most commonly occur in patients with prior heart surgery or catheter ablation. The ECG pattern is poorly predictive of circuit anatomy but may still provide mechanistic insight. AFL is difficult to manage medically and catheter ablation is the preferred treatment for most patients. Recent progress in technology and clinical electrophysiology has led to detailed characterization of re-entry circuits and effective ablation strategies. Combined activation and entrainment mapping are key to identifying the re-entry circuit. The presence of a slow-conducting isthmus, localized re-entry, dual-loop re-entry or bystander loops may lead to misleading activation maps but can be identified by electrogram examination and entrainment mapping. In the occasional patient without inducible AFL, substrate mapping in sinus rhythm may be a viable strategy. Long-term ablation success requires the creation of a transmural continuous lesion across a critical component of the re-entry circuit. Procedural endpoints include bidirectional conduction block across linear lesions and non-inducibility of atrial tachycardia. The present review discusses the epidemiology, mechanisms, ECG characteristics, electrophysiological characterization, and catheter ablation of atypical AFL.

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

BACKGROUND

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.

OBJECTIVE

To characterize scar formation after EI-VOM, and its impact on LA function, by cardiac magnetic resonance (CMR).

METHODS

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.

RESULTS

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.

CONCLUSION

EI-VOM causes permanent scarring at 3-month follow-up, with no adverse impact on CMR LA functional parameters.

Coronary Sinus Isolation for High-Burden Atrial Fibrillation: A Randomized Clinical Trial

BACKGROUND

The coronary sinus is an arrhythmogenic structure that can initiate and maintain atrial fibrillation (AF). Coronary sinus ablation has been shown to be effective in prolonging the AF cycle length and terminating AF in patients with both paroxysmal and persistent AF who have persistent AF after pulmonary vein isolation (PVI).

OBJECTIVES

The objective of this study was to undertake a randomized controlled trial to investigate the efficacy of coronary sinus isolation (CSI) as an adjunctive ablation strategy for the treatment of high-burden AF.

METHODS

Consecutive patients presenting with symptomatic long episodes of paroxysmal AF (≥48 h but ≤7 days) or persistent AF (>7 days and ≤12 months) referred for first-time ablation were enrolled. Participants were randomized to either PVI, roofline ablation, and CSI (CSI group) or PVI and roofline ablation only (non-CSI group). Participants were assessed postprocedurally via clinical follow-up and 7-day Holter monitoring at regular intervals. The primary outcome was single-procedure drug-free atrial arrhythmia-free survival at 2 years.

RESULTS

A total of 100 participants were recruited to the study; 48 were randomized to the CSI group and 52 to the non-CSI group. Acutely successful CSI was achieved in 45 of the 48 patients in the CSI group. At 2 years follow up, 30 of 48 patients (62.5%) in the CSI group and 33 of 52 (63.4%) in the non-CSI group were free from arrhythmia recurrence. Single-procedure drug-free survival at 2 years was no different between groups (P = 0.91). Similarly, multiple procedure drug assisted survival at 5 years was not different between groups (P = 0.80). Complication rates were not significantly different between groups (P = 0.19).

CONCLUSIONS

Adjunctive CSI as part of a de novo ablation strategy does not confer any additional benefit greater than PVI and roofline for the treatment of high-burden AF.

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.

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.

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

BACKGROUND

Reconnection 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.

OBJECTIVES

This study sought to determine anatomic substrates of failed MI ablation, with and without VOMEI.

METHODS

Consecutive 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.

RESULTS

In 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).

CONCLUSIONS

MI 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.

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.

Ablation Strategies for Persistent Atrial Fibrillation: Beyond the Pulmonary Veins

Despite advances in ablative therapies, outcomes remain less favorable for persistent atrial fibrillation often due to presence of non-pulmonary vein triggers and abnormal atrial substrates. This review highlights advances in ablation technologies and notable scientific literature on clinical outcomes associated with pursuing adjunctive ablation targets and substrate modification during persistent atrial fibrillation ablation, while also highlighting notable future directions.

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.

Posterior left atrial isolation is associated with a lower incidence of atrial tachycardia in patients with persistent atrial fibrillation

BACKGROUND

Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF).

METHODS

The population consisted of 101 consecutive patients (age = 64.3 ± 8.7 years, 70 males (69%), LA = 4.6 ± 0.8 cm, ejection fraction = 48.5 ± 16%) undergoing their initial procedure for persistent AF. After pulmonary vein isolation, patients either underwent posterior LA isolation (n = 50; study group) or linear ablation at the LA roof with verification of conduction block (n = 51; control group).

RESULTS

A repeat procedure was performed in 17 (34%) and 28 (55%) patients in the study and control groups, respectively (p = 0.02). Patients in the study group were less likely to develop AT (9/50 [18%] vs. 18/51 [35%]; p = 0.02), roof-dependent (1/50 [2%] vs. 8/51 [16%]; p = 0.008), and multi-loop AT (6/50 [12%] vs. 14/51 [27%]; p = 0.03) as compared to controls. Among various factors, only posterior LA isolation was associated with a lower likelihood of AT recurrence and roof tachycardia at redo procedure (OR, 0.37; 95% CI, 0.1 to 1.00, p = 0.05, and OR, 0.1, 95% CI, 0.01 to 0.96; p < 0.05, respectively).

CONCLUSIONS

In patients with persistent AF, posterior LA isolation is associated with a lower risk of a redo procedure, roof-dependent macro-reentry, and post-ablation AT in general as compared to controls who only received roof ablation. Posterior LA isolation also obviates the need for pacing maneuvers, and may be a more definitive endpoint than linear ablation at the LA roof.

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.

Anatomical and Electrophysiological Characteristics of Dual-Loop Re-Entry in Atypical Atrial Flutter: Implications for Mapping and Catheter Ablation

Background: Atypical atrial flutter (AFL) can be challenging to ablate, especially when involving dual-loop re-entry. We sought to assess the electroanatomical characteristics of single- and dual-loop AFLs in patients undergoing catheter ablation. Methods: We analyzed 25 non-cavotricuspid isthmus-dependent macro-re-entrant AFL in 19 consecutive patients. Three-dimensional high-density activation mapping was performed, and active re-entry loops were confirmed by entrainment mapping. Results: Of 25 AFLs (24 left, 1 right atrial), 13 (52%) exhibited dual-loop re-entry. The most common circuits included, in 6/13 (46% of dual loops), a perimitral re-entry with a second loop around the right/left pulmonary veins (PV) and, in 6/13 (46%), involved a right PV ostium with a second loop around either a functional conduction block or another PV. Ablation at the common isthmus of dual-loop AFLs and at the critical isthmus of single-loop AFLs terminated the arrhythmia more frequently than ablation at a secondary isthmus of dual-loop AFLs (5/6 (83%) and 8/11 (73%) versus 1/8 (13%), respectively, p = 0.013). Conclusions: More than half of AFLs exhibited a dual-loop re-entrant mechanism. Most critical isthmuses were found at the mitral isthmus, the left atrial roof or right PV ostia. Ablation targeting the common isthmus resulted in a higher termination rate.

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 .

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.

Prospective randomized comparison between upgraded '2C3L' vs. PVI approach for catheter ablation of persistent atrial fibrillation: PROMPT-AF trial design

BACKGROUND

In randomized studies, the strategy of pulmonary vein antral isolation (PVI) plus linear ablation has failed to increase success rates for persistent atrial fibrillation (PeAF) ablation when compared with PVI alone. Peri-mitral reentry related atrial tachycardia due to incomplete linear block is an important cause of clinical failures of a first ablation procedure. Ethanol infusion (EI) into the vein of Marshall (EI-VOM) has been demonstrated to facilitate a durable mitral isthmus linear lesion.

OBJECTIVE

This trial is designed to compare arrhythmia-free survival between PVI and an ablation strategy termed upgraded '2C3L' for the ablation of PeAF.

STUDY DESIGN

The PROMPT-AF study (clinicaltrials.gov 04497376) is a prospective, multicenter, open-label, randomized trial using a 1:1 parallel-control approach. Patients (n = 498) undergoing their first catheter ablation of PeAF will be randomized to either the upgraded '2C3L' arm or PVI arm in a 1:1 fashion. The upgraded '2C3L' technique is a fixed ablation approach consisting of EI-VOM, bilateral circumferential PVI, and 3 linear ablation lesion sets across the mitral isthmus, left atrial roof, and cavotricuspid isthmus. The follow-up duration is 12 months. The primary end point is freedom from atrial arrhythmias of >30 seconds, without antiarrhythmic drugs, in 12 months after the index ablation procedure (excluding a blanking period of 3 months).

CONCLUSIONS

The PROMPT-AF study will evaluate the efficacy of the fixed '2C3L' approach in conjunction with EI-VOM, compared with PVI alone, in patients with PeAF undergoing de novo ablation.

Feasibility of Linear Irreversible Electroporation Ablation in the Coronary Sinus

INTRODUCTION

Previous studies demonstrated that the coronary sinus (CS) is an important target for ablation in persistent atrial fibrillation. However, radiofrequency ablation in the CS is associated with coronary vessel damage and tamponade. Animal data suggest irreversible electroporation (IRE) ablation can be a safe ablation modality in vicinity of coronary arteries. We investigated the feasibility of IRE in the CS in a porcine model.

METHODS

Ablation and pacing was performed in the CS in six pigs (weight 60-75 kg) using a modified 9-French steerable linear hexapolar Tip-Versatile Ablation Catheter. Pacing maneuvers were performed from distal to proximal segments of the CS to assess atrial capture thresholds before and after IRE application. IRE ablations were performed with 100 J IRE pulses. After 3-week survival animals were euthanized and histological sections from the CS were analyzed.

RESULTS

A total of 27 IRE applications in six animals were performed. Mean peak voltage was 1509 ± 36 V, with a mean peak current of 22.9 ± 1.0 A. No complications occurred during procedure and 3-week survival. At 30 min post ablation 100% isolation was achieved in all animals. At 3 weeks follow-up pacing thresholds were significant higher as compared to baseline. Histological analysis showed transmural ablation lesions in muscular sleeves surrounding the CS.

CONCLUSION

IRE ablation of the musculature along the CS using a multi-electrode catheter is feasible in a porcine model.

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.

Gaps after linear ablation of persistent atrial fibrillation (Marshall-PLAN): Clinical implication

BACKGROUND

Beyond pulmonary vein (PV) isolation, anatomic isthmus transection is an adjunctive strategy for persistent atrial fibrillation. Data on the durability of multiple lines of block remain scarce.

OBJECTIVE

The purpose of this study was to evaluate the impact of gaps within such a lesion set.

METHODS

We followed 291 consecutive patients who underwent (1) vein of Marshall ethanol infusion, (2) PV isolation, and (3) mitral, cavotricuspid, and dome isthmus transection. Dome transection relied on 2 distinct strategies over time: a single roof line with touch-ups applied in case of gap demonstrated by conventional maneuvers (first leg), and an alternative floor line if the roof line exhibited a gap during high-density mapping with careful electrogram reannotation (second leg).

RESULTS

Twelve-month sinus rhythm maintenance was 70% after 1 procedure and 94% after 1 or 2 procedures. Event-free survival after the first procedure was lower in case of residual gaps within the lesion set (log-rank, P = .004). Delayed gaps were found in 94% of a second procedure performed in the 69 patients relapsing despite a complete lesion set with PV gaps increasing the risk of recurrence of atrial fibrillation (67% vs 34%; P = .02) and anatomic isthmus gaps supporting a majority of atrial tachycardias (60%). Between the first leg and the second leg, a significant decrease was found in roof lines considered blocked during the first procedure (99% vs 78%; P < .001) and in delayed dome gaps observed during a second procedure (68% vs 43%; P = .05).

CONCLUSION

Gaps are arrhythmogenic and can be reduced by optimized ablation and assessment of lines of block. Closing these gaps improves sinus rhythm maintenance.

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.

Right atrial appendage firing in atrial fibrillation

Background

The role of atrial fibrillation (AF) drivers located at the left atrium, superior vena cava, crista terminalis and coronary sinus (CS) is well established. While these regions are classically targeted during catheter ablation, the role of right atrial appendage (RAA) drivers has been incompletely investigated.

Objective

To determine the prevalence and electrophysiological characteristics of AF driver’s arising from the RAA.

Materials and methods

We conducted a retrospective analysis of clinical and procedural data of 317 consecutive patients who underwent an AF ablation procedure after bi-atrial mapping (multipolar catheter). We selected patients who presented with a per-procedural RAA firing (RAAF). RAAF was defined as the recording of a sustained RAA EGM with a cycle length shorter than 120 ms or 120 &lt; RAAF CL ≤ 130 ms and ratio RAA CL/CS CL ≤ 0.75.

Results

Right atrial/atrium appendage firing was found in 22 patients. The prevalence was estimated at 7% (95% CI, 4–10). These patients were mostly men (72%), median age: 66 yo ± 8 without structural heart disease (77%). RAAFs were predominantly found in paroxysmal AF patients (63%, 32%, and 5% for paroxysmal, short standing and long-standing AF, respectively, p &gt; 0.05). RAAF median cycle length was 117 ms ± 7 while CS cycle length was 180 ms ± 10 (p &lt; 0.01).

Conclusion

In 317 consecutive AF ablation patients (22 patients, 7%) the presence of a high-voltage short-cycle-length right atrial appendage driver (RAAF) may conclusively be associated with AF termination. This case series exemplifies the not-so-uncommon role of the RAA in the perpetuation of AF.

The Maine vein of Marshall ethanol experience: learning curve and safety

BACKGROUND

The marginal benefit of ethanol infusion into the vein of Marshall (VOM) as an adjunct to atrial fibrillation ablation has shown promise in a single randomized study and case series from very experienced centers. However, adoption has not been widespread and the impact on real-world outcomes outside of leading centers is not established. The objective in this study is to understand the learning curve, and explore procedural outcomes and safety with VOM ethanol infusion from a large single medical center.

METHODS

One hundred twenty nine 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). Our technical approach, procedural success, and complications were adjudicated from the medical record.

RESULTS

The overall VOM ethanol infusion success was 90%. Infusion success rates improved and fluoroscopy utilization decreased with experience. Arrhythmia recurrence was 14% after a mean follow-up of 9.5 months. Complications occurred in 5.4% of patients, including a 3.1% risk of delayed tamponade.

CONCLUSION

In our single center experience, VOM ethanol infusion was feasible with a high technical success rate. These positive results are balanced against a concerning rate of delayed tamponade.

Ethanol Infusion of Vein of Marshall for the Treatment of Persistent Atrial Fibrillation: The Basics and Clinical Practice

Catheter ablation for persistent atrial fibrillation (PeAF) is particularly challenging, as the clinical outcomes are modest. Pulmonary vein isolation (PVI) plus linear ablation is one of the main strategies for PeAF ablation. Completely durable transmural lesions are difficult to achieve by catheter ablation during mitral isthmus ablation. The ligament of Marshall contains the vein of Marshall (VOM), myocardial tracts and innervation, and serves as arrhythmogenic foci that make it an attractive target in catheter ablation of atrial fibrillation. Additionally, it co-localizes with the mitral isthmus, and may serve as a part of the perimitral isthmus reentrant circuit. Ethanol infusion into the VOM results in rapid ablation of the neighboring myocardium and its innervation. Its incorporation into PVI significantly increases the success rate of mitral isthmus block and the clinical outcome of PeAF ablation.

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.

Ten Steps in Adoption of Emerging Procedural Techniques: An Experience With Ethanol Ablation of Vein of Marshall (VOM)

Proceduralists must update their skill sets to provide patients with better care because of the addition of new and effective strategies post-training. For example, the current procedural strategy of pulmonary vein isolation for treating persistent atrial fibrillation (AF) is inadequate. However, the addition of ethanol ablation of the vein of Marshall (VOM), a relatively new procedural technique, can improve outcomes. Furthermore, the purpose of this report was to briefly explain VOM ethanol ablation, its role in atrial fibrillation and atypical flutter ablation, and to provide a template for performing a new procedural technique in the field.

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.

Single-catheter simplified stepwise approach to persistent atrial fibrillation ablation: A feasibility study

BACKGROUND

The strategy for atrial fibrillation ablation in persistent atrial fibrillation remains controversial. A single-catheter approach was recently validated for pulmonary vein isolation.

AIM

To evaluate the feasibility of this approach to performing persistent atrial fibrillation ablation, including pulmonary vein isolation and atrial lines, if needed.

METHODS

We prospectively included 159 consecutive patients referred to our centre for a first persistent atrial fibrillation ablation between January 2018 and December 2018. All patients underwent pulmonary vein isolation. If the patient was still in atrial fibrillation (spontaneously or inducible), we subsequently performed a stepwise approach, including roof line, anterior mitral line, posterior box lesion and cavotricuspid isthmus line. Finally, if patient remained in atrial fibrillation at the end of the procedure, a synchronized direct-current cardioversion was applied to restore sinus rhythm.

RESULTS

At baseline, 54 patients were in sinus rhythm and underwent pulmonary vein isolation. For patients in atrial fibrillation, after pulmonary vein isolation and ablation of additional lines, if needed, 18 patients were converted to atrial tachycardia and one directly to sinus rhythm; 96 were still in atrial fibrillation and underwent direct-current cardioversion. After a mean follow-up of 17±6 months, 57 patients (36%) experienced atrial arrhythmia recurrence. No deaths, tamponades or phrenic nerve injuries were observed following the procedure. The main mode of arrhythmia recurrence was atrial fibrillation in 75% of cases and atrial tachycardia in 25% of cases.

CONCLUSION

A single-catheter approach, including pulmonary vein isolation and atrial lines, is feasible and safe in patients undergoing persistent atrial fibrillation ablation, with an acceptable success rate of 64% at mid-term follow-up.

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.

Vein of Marshall Ethanol Infusion: Feasibility, Pitfalls, and Complications in Over 700 Patients

Supplemental Digital Content is available in the text.

Vein of Marshall (VOM) ethanol infusion is a relatively new therapeutic option for atrial tachyarrhythmias. We aimed to evaluate the feasibility, pitfalls, and complications associated with this procedure in a large cohort of patients.

Vein of Marshall ethanol infusion in the treatment of atrial fibrillation: From concept to clinical practice

The vein of Marshall (VOM) contains innervation, myocardial connections, and arrhythmogenic foci that make it an attractive target in catheter ablation of atrial fibrillation (AF). Additionally, it co-localizes with the mitral isthmus, which is critical to sustain perimitral flutter, and is a true atrial vein that communicates with underlying myocardium. Retrograde balloon cannulation of the VOM from the coronary sinus is feasible and allows for ethanol delivery, which results in rapid ablation of neighboring myocardium and its innervation. Here we review the body of work performed over a span of 13 years, from the inception of the technique, to its preclinical validation, to demonstration of its ablative and denervation effects, and finally to completion of a randomized clinical trial demonstrating favorable outcomes, improving rhythm control in catheter ablation of persistent AF.

Epicardial course of the musculature related to the great cardiac vein: Anatomical considerations and clinical implications for mitral isthmus block after vein of Marshall ethanol infusion

BACKGROUND

Mitral isthmus gaps have been ascribed to an epicardial musculature anatomically related to the great cardiac vein (GCV) and the vein of Marshall (VOM). Their lumen offers an access for radiofrequency application or ethanol infusion, respectively.

OBJECTIVE

The purpose of this study was to evaluate the frequency of mitral isthmus gaps accessible via the GCV lumen, to assess their location around the GCV circumference, and to propose an efficient ablation strategy when present.

METHODS

One hundred consecutive patients underwent VOM ethanol infusion (step 1) and endocardial linear ablation from the mitral annulus to the left inferior pulmonary vein (step 2). In cases of mitral isthmus gap, endovascular ablation of the GCV anchored wall facing the left atrium was systematically performed (step 3), while the opposite GCV free wall was targeted in case of block failure only (step 4).

RESULTS

After VOM ethanol infusion and endocardial ablation, mitral isthmus block occurred in 51 patients (51%). Pacing maneuvers and activation sequences demonstrated an epicardial gap via the VOM in 2 patients (2%) and via the GCV in 47 patients (47%). In the latter case, block was achieved at the GCV anchored wall in 42 patients (89%) and the GCV free wall in 5 patients (11%). Global success rate of mitral isthmus block was 98%. No tamponade occurred.

CONCLUSION

With the advent of VOM ethanol infusion, residual mitral isthmus gaps are mostly eliminated within the first centimeter of the GCV. Thorough mapping of the entire circumference of the GCV wall can help identify these epicardial gaps.

Effectiveness of ethanol infusion into the vein of Marshall combined with a fixed anatomical ablation strategy (the "upgraded 2C3L" approach) for catheter ablation of persistent atrial fibrillation

INTRODUCTION

Linear ablation in addition to pulmonary vein antrum isolation (PVAI) has failed to improve the success rate for persistent atrial fibrillation (PeAF), due to incomplete block of ablation lines, especially in the mitral isthmus (MI).

METHODS AND RESULTS

The study enrolled 191 patients (66 in group 1 and 125 in group 2). In group 1, ethanol infusion into the vein of Marshall was first performed, followed by radiofrequency (RF) applications targeting bilateral PVAI and bidirectional block in the roofline, cavotricuspid isthmus, and MI. In group 2, PVAI and the three linear ablations were completed using only RF energy. MI block was achieved in 63 (95.5%) and 101 (80.8%) patients in groups 1 and 2, respectively (p = .006). Patients in group 1 had shorter ablation time for left pulmonary vein antrum (8.15 vs. 12.59 min, p < .001) and MI (7.0 vs. 11.8 min, p < .001) and required less cardioversion (50 [78.5%] vs. 113 [90.4%], p = .007). During the 12-month follow-up, 58 (87.9%) patients were free from atrial fibrillation/atrial tachycardia in group 1 compared with 81 (64.8%) in group 2 (p < .001). In multivariate cox regression, the "upgraded 2C3L" procedure is associated with a lower recurrence rate (hazard ratio = 0.27, 95% confidence interval = 0.12-0.59).

CONCLUSION

Compared with the conventional "2C3L" approach, the "upgraded 2C3L" approach has higher effectiveness for ablation of PeAF.

Feasibility, efficacy, and safety of ethanol infusion into the vein of Marshall for atrial fibrillation: A meta-analysis

BACKGROUND

Contemporary radiofrequency catheter ablation (RFCA) approaches for atrial fibrillation (AF) have reached an efficacy "ceiling". Ethanol infusion into the vein of Marshall (EI-VOM) has shown potential in preliminary studies. Data on EI-VOM are largely limited to small single-center reports, and clinical benefits and risks have not been systematically examined. Therefore, we performed a meta-analysis to assess the feasibility, efficacy, and safety of EI-VOM for AF.

METHODS

All studies evaluating EI-VOM for AF were initially searched from four electronic search engines: PubMed, Web of Science, Cochrane Library, and SinoMed. We used RevMan5.4 to calculate pooled outcomes of randomized controlled trial and cohort studies. We also performed single-arm meta-analyses using Open Meta-Analyst.

RESULTS

We included a total of 10 studies with 1322 patients. Successful EI-VOM was performed in 86.7% (95% CI 81.9-91.4%) of patients. For persistent AF patients, the recurrence of AF and/or atrial tachycardia (AT) was significantly lower in the EI-VOM combined with RFCA group compared with RFCA alone group (RR 0.58, 95% CI 0.35 to 0.96, p = 0.04). EI-VOM combined with RFCA significantly increased the rate of bidirectional mitral isthmus block compared with RFCA alone in AF patients (RR 1.50, 95% CI 1.34 to 1.67, p < 0.001). There were nine cardiac tamponades observed in 644 patients (PR 0.8%, 95% CI 0.1-1.5%) who were performed EI-VOM combined with RFCA.

CONCLUSIONS

Our meta-analysis brings encouraging evidence that adjuvant EI-VOM reduces AF and/or AT recurrence rate in persistent AF patients and increases the success rate of bidirectional mitral isthmus block.

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.

Ligament of Marshall ablation for persistent atrial fibrillation

Beyond pulmonary vein isolation, the two main additional strategies: Cox-Maze procedure or targeting of electrical signatures (focal bursts, rotational activities, meandering wavelets), remain controversial. High-density mapping of these arrhythmias has demonstrated firstly that a patchy lesion set is highly proarrhythmogenic, favoring macro-re-entry through conduction slowing and providing pivots for localized re-entry. Secondly, discrete anatomical structures such as the Vein or Ligament of Marshall (VOM/LOM) and the coronary sinus (CS) have epicardial muscular bundles that are more frequently involved in re-entry than previously thought. The Marshall Bundle can be ablated at any point along its course from the mid-to-distal coronary sinus to the left atrial appendage. If necessary, the VOM may be directly ablated using ethanol infusion to eliminate PV contributions and produce conduction block across the mistral isthmus. Ethanol ablation of the VOM, supplemented with RF ablation, may be more effective in producing conduction block at the mitral isthmus than repeat RF ablation alone.

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.

Approach to recurrence of atrial fibrillation after catheter ablation

Atrial fibrillation (AF) is the most commonly observed sustained rhythm disorder during adult ages. Since it has been shown that the ectopic beat initiating AF is usually caused by pulmonary veins, AF ablation has become the mainstay of therapy worldwide. Cryoballoon and radiofrequency ablation are the most commonly used methods in today's technologies. However, despite technological advances, the success of a single procedure in AF ablation is still limited and multiple procedures may be required for the majority of patients. In cases in which a redo ablation is required, pulmonary vein isolation is still the main target, but non-pulmonary vein targets should also be considered in AF episodes that continue despite multiple ablations. Many issues are still unclear as to which energy to choose in the first procedure, and what ablation strategy will be utilized when a redo ablation is required. The studies on this subject are very limited but, it still seems feasible and a rational approach to utilize a customized treatment strategy in each specific patient subgroup.

Atrial Fibrillation (Part 2) - Catheter Ablation

More than 20 years since its initial use, catheter ablation has become a routinely performed procedure for the treatment of patients with atrial fibrillation (AF). Initially based on the electrical isolation of pulmonary veins in patients with paroxysmal AF, subsequent advances in the understanding of pathophysiology led to additional techniques not only to achieve better results, but also to treat patients with persistent forms of arrhythmia, as well as patients with structural heart disease and heart failure.