Quick Dive: Epicardial ventricular arrhythmia ablation

What is the reason for and aim of the publication?

The need for this clinical consensus statement arose from the growing recognition that many ventricular arrhythmias (VAs) originate from intramural or epicardial substrates, which are often inaccessible with standard endocardial ablation. Epicardial access is therefore necessary in 25–30 % of VA ablations. Given the complexity, risks, and resource demands of epicardial procedures and their limited application to select patient populations and experienced centers, there is a need for structured guidance.

The aim is to guide clinicians in the management of epicardial VA ablation across a variety of clinical scenarios by offering structured advice and a systematic approach to patient care. The document addresses many aspects of epicardial ablation, including, but not limited to, anatomical considerations, criteria for epicardial access and mapping, procedural techniques, complication management, training, and institutional requirements.

What are the most important take-home messages?

1. Careful patient selection is key: Epicardial ablation is indicated in ~1/3 of VA ablation cases, especially in patients with specific cardiomyopathies or evidence of epicardial substrate on ECG, imaging, or mapping.
2. Tailor the access approach: Subxiphoid percutaneous puncture is standard, but prior surgeries or adhesions may necessitate surgical or hybrid access strategies, with tools like CO₂ insufflation enhancing safety.
3. Use cardiac imaging for planning and guidance: Pre-procedural MRI or CT, image integration into mapping systems, and coronary angiography improve anatomical understanding and procedural precision.
4. Manage anticoagulation with caution: Uninterrupted anticoagulation is not advised. Adjustments should be individualized, and an INR <1.5 is recommended before the procedure.
5. Prevent and manage complications proactively: Knowledge of pericardial and coronary anatomy is essential. Be prepared for pericarditis, tamponade, coronary and phrenic nerve injury, especially in high-risk patients.
6. Adapt mapping and ablation techniques: Use multimodal strategies (e.g., voltage mapping, pace mapping) and aim for endpoints like VT noninducibility and late potential elimination to ensure effectiveness.
7. Implement comprehensive post-procedure care: This includes pericardial drainage, imaging, anticoagulation management, device interrogation, and use of colchicine/steroids to reduce inflammation and adhesions.
8. Ensure structured follow-up: Follow-up at 4–8 weeks and beyond is essential to monitor for recurrence and reassess the need for ongoing antiarrhythmic therapy based on procedural outcome.
9. Prioritize operator training and institutional readiness: Epicardial procedures require dedicated expertise. Perform them in experienced centers with surgical backup and promote simulation-based learning.
10. Incorporate evolving technologies: Emerging tools — such as novel catheters, advanced imaging integration, and pulsed field ablation — may improve procedural safety and efficacy in the future.
    

What are challenges in practical implementation – and possible solutions?

1. Challenge: Limited operator experience and training

Explanation: Epicardial ablation techniques differ significantly from standard endocardial approaches and are associated with higher risks. Few centers and operators have sufficient experience.

Solution: Promote structured training programs, including simulation-based education. Foster mentorship by experienced operators. Perform procedures in high-volume tertiary centers with surgical backup.

2. Challenge: Risk of major complications

Explanation: These include pericardial bleeding, tamponade, coronary artery injury, phrenic nerve damage, and pericarditis.

Solution: Careful patient selection using imaging and risk scores (e.g., PAINESD). Use of adjunct tools like coronary angiography, phrenic nerve pacing, and imaging integration. Application of preventive strategies like intrapericardial steroids and colchicine.

3. Challenge: Difficult epicardial access in patients with prior surgery or adhesions

Explanation: Pericardial adhesions after cardiac surgery or prior interventions can prevent safe access.

Solution: Consider hybrid surgical-electrophysiology approaches. Use of CO₂ insufflation to enhance safety. Surgical epicardial access in selected patients.

4. Challenge: Epicardial fat and anatomic barriers impair ablation effectiveness

Explanation: Epicardial fat limits radiofrequency lesion formation; proximity to coronary vessels limits ablation zones.

Solution: Use of high-output energy delivery when safe. Careful pre-procedural planning with MRI/CT to assess fat and anatomy. Evaluate new energy sources (e.g., pulsed field ablation) that may overcome these limitations.

5. Challenge: Standardized protocols for anticoagulation and post-procedural care

Explanation: Unclear best practices for managing anticoagulation, pericardial drainage, and anti-inflammatory treatment.

Solution: Adopt consensus recommendations (e.g., INR <1.5 before procedure, use of colchicine/steroids post-ablation). Develop institution-specific protocols aligned with expert consensus.

6. Challenge: Incomplete substrate elimination and arrhythmia recurrence

Explanation: Epicardial ablation may miss intramural or complex substrates, leading to recurrence.

Solution: Perform thorough mapping. Consider combined endocardial-epicardial approaches. Tailor post-procedural follow-up and antiarrhythmic therapy individually.

Which issues still need to be tackled, that are not yet addressed by the paper?

1. Need for standardized long-term outcome data: While procedural guidance is detailed, we need to provide standardized data on long-term outcomes (e.g., recurrence rates, survival benefit). To provide these data, Multicenter prospective registries and long-term studies are needed to assess efficacy and safety.
2. Limited data on the role of new ablation technologies and energy sources: Novel mapping techniques like multilayer and multielectrode mapping and new energy sources such as pulsed field ablation are mentioned. However, we need comparative studies and a consensus on how emerging technologies can be safely and effectively used in the epicardial space.
3. Sparse discussion on pediatric or congenital heart disease populations. The consensus is primarily focused on adult populations with structural heart disease. Specific guidance is needed, tailored to pediatric patients and those with congenital heart anomalies requiring epicardial access.
4. The Emerging Role of Artificial Intelligence (AI). AI is increasingly playing a transformative role in catheter ablation, including epicardial procedures, with potential applications in patient selection, substrate characterization, procedural planning, outcome prediction, and automation and efficiency. As AI continues to evolve, it will likely play an increasingly central role in optimizing procedural workflows, reducing operator variability, and improving patient outcomes in epicardial and endocardial ablation alike.
   

What further developments on the topic are emerging?

Further developments emerging in the field of epicardial VA ablation focus on improving safety, efficacy, and accessibility. According to Section 11 of the consensus document, key areas of ongoing and future progress include:

1. Refinement of radiofrequency (RF) energy delivery: Research is ongoing into contact force in epicardial space, optimal RF power and duration, and techniques to increase lesion depth and penetration to enhance lesion formation while minimizing risk.
2. Better assessment of lesion characteristics: Development of tools and methods to assess lesion size and depth in real time during epicardial ablation using RF or PFA energy sources is a major research focus.
3. Integration of anatomical structures into mapping: Advances are underway to improve 3D electroanatomical mapping by incorporating the location and thickness of epicardial fat, which currently limits lesion effectiveness.
4. Enhanced safety around vital structures: Future strategies aim to improve detection and protection of coronary arteries and the phrenic nerve during ablation procedures.
5. Exploration of new energy sources: Promising alternative energy modalities include: Cryoablation (including ultra-low temperature systems), PFA, and High-intensity focused ultrasound.
6. Optimization of anticoagulation protocols: More data are needed to define best practices for anticoagulation, especially around the timing of interruption and resumption of therapy in epicardial cases.
7. Redefining the role of cardiac surgery: With the advancement of safer access and ablation techniques, the role of on-site cardiac surgery may shift, possibly reducing the need for immediate surgical support or changing referral patterns.
   

Clinical consensus statement: Epicardial ventricular arrhythmia ablation

Arya A, Di Biase L, Bazán V et al. Epicardial ventricular arrhythmia ablation: a clinical consensus statement of the European Heart Rhythm Association of the European Society of Cardiology and the Heart Rhythm Society, the Asian Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society, and the Canadian Heart Rhythm Society, EP Europace, Volume 27, Issue 4, April 2025, euaf055, https://doi.org/10.1093/europace/euaf055

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