Upgrade on atrial fibrillation ablation in the new ESC Guidelines

Abstract

Clinical guidelines (GLs) are crafted by professional medical societies with the primary goal of supporting healthcare providers in making informed decisions during routine clinical practice. These GLs serve as practical tools, offering evidence-based recommendations that help clinicians navigate complex scenarios in patient care. By synthesizing the latest scientific evidence and expert consensus, they provide a structured framework for diagnosing, managing, and preventing various medical conditions. This ensures that clinical decision-making is consistent, effective, and aligned with current best practices, ultimately promoting high-quality care and better patient outcomes in everyday healthcare settings. This paper aims to emphasize the importance of updating the European Society of Cardiology 2020 GLs, particularly in light of advances and evolving evidence in the management of atrial fibrillation (AF). It examines the key updates introduced in the 2024 GLs, with a specific focus on AF ablation, highlighting the changes and advancements that address gaps or enhance clinical practices. Additionally, the paper explores potential future directions for refining these GLs, considering emerging research, evolving technologies, and practical challenges in their implementation including new editing methods.

Introduction

Clinical guidelines (GLs) are crafted by professional medical societies with the primary goal of supporting healthcare providers in making informed decisions during routine clinical practice. These GLs serve as practical tools, offering evidence-based recommendations that help clinicians navigate complex scenarios in patient care. By synthesizing the latest scientific evidence and expert consensus, they provide a structured framework for diagnosing, managing, and preventing various medical conditions. This ensures that clinical decision-making is consistent, effective, and aligned with current best practices, ultimately promoting high-quality care and better patient outcomes in everyday healthcare settings.

The prevalence of atrial fibrillation (AF) is projected to double by 2050, driven by a combination of factors. These include the ageing population, a growing burden of associated comorbidities, heightened awareness of the condition, and advancements in diagnostic technologies that facilitate earlier and more accurate detection.

To address this escalating global challenge, the European Society of Cardiology (ESC) published new 2024 GLs for the management of AF,¹ developed in partnership with the European Association of Cardio-Thoracic Surgery (EACTS), introducing a series of innovative strategies and treatment-specific recommendations. These updated GLs aim to optimize care for the increasing number of AF patients worldwide by combining evidence-based approaches with expert opinion (EO) and integrating new therapeutic advancements adapted to the evolving healthcare needs.

This paper provides a detailed examination of the significant updates introduced in the 2024 GLs, with particular emphasis on AF ablation, and seeks to underscore the critical importance of revising and updating the ESC 2020 GLs,² especially in response to recent advances and emerging evidence in the management of AF.

Furthermore, the paper addresses existing gaps in evidence and delves into potential future directions for the continued evolution of GLs proposing an alternative editing method.

This forward-looking approach aims to ensure that AF management GLs remain dynamic and responsive to the rapidly progressing landscape of cardiovascular medicine reinforcing the adherence to evidence-based medicine.

2024 European Society of Cardiology guidelines on atrial fibrillation: focus on ablation

The 2024 ESC GLs on AF have been developed to provide healthcare professionals with up-to-date, evidence-based recommendations and expert insights to support the effective diagnosis and management of AF.¹ These GLs are intended to assist clinicians in tailoring diagnostic and therapeutic approaches to the individual needs of each patient, considering their specific clinical profile and comorbidities. The 2024 ESC GLs place a strong emphasis on the importance of managing comorbidities and controlling risk factors as essential strategies for both primary and secondary prevention of AF. This holistic approach emphasizes that controlling underlying conditions is essential not only for reducing the burden of AF but also for preventing its recurrence.

Within this framework, AF ablation is positioned as an important intervention that must be integrated into a broader, multifaceted treatment strategy. Rather than viewing ablation in isolation, the GLs encourage its use as one component of a larger, individualized plan that considers all aspects of patient care, highlighting its value as a piece of the complex puzzle of AF management.

2024 European Society of Cardiology guidelines on ablation of atrial fibrillation

Shared decision-making

Shared decision-making is recommended when considering catheter ablation for AF, taking into procedural risks, likely benefits, and risk factors for AF recurrence.

Class I Level C

A patient-centred and integrated approach to managing AF involves adopting a care model that prioritizes and respects the patient’s unique experiences, values, needs, and preferences throughout the planning, coordination, and delivery of care. At the heart of this approach lies the therapeutic relationship between the patient and a multidisciplinary team of healthcare professionals. This model emphasizes collaboration, where patients are not treated as passive recipients of medical interventions but as empowered, active participants. They work in partnership with healthcare providers, contributing to decision-making and playing a central role in shaping their treatment journey.

Rhythm control

Catheter ablation is recommended in patients with paroxysmal or persistent AF resistant or intolerant to antiarrhythmic drug therapy to reduce symptoms, recurrence, and progression of AF.

Class I Level A

Catheter ablation is recommended as a first-line option within a shared decision-making rhythm control strategy in patients with paroxysmal AF, to reduce symptoms, recurrence, and progression of AF.

Class I Level A

Catheter ablation may be considered as a first-line option within a shared decision-making rhythm control strategy in selected patients with persistent AF to reduce symptoms, recurrence, and progression of AF.

Class IIb Level C

The proposed scheme indicates that catheter ablation is now regarded as an established intervention for preventing AF recurrences, reducing AF burden, and improving quality of life, particularly in patients with symptomatic paroxysmal or persistent AF who either cannot tolerate or do not respond to antiarrhythmic drugs (AADs).^3,4

In the past, GLs strongly recommended catheter ablation for AF primarily as a secondary option, reserved for symptomatic patients who did not achieve adequate control with AADs. However, the 2024 GLs represent a shift in approach. They now support considering catheter ablation as a potential first-line treatment option for selected patients. This recommendation emphasizes the importance of individualized care, encouraging physicians to engage in thorough discussions with patients about the risks, benefits, and potential outcomes of ablation. This collaborative decision-making process allows patients to choose ablation as an initial therapy when it aligns with their preferences and clinical circumstances.

Numerous randomized controlled trials (RCTs) have demonstrated that catheter ablation can serve as a first-line strategy for rhythm control in patients with paroxysmal AF, showing comparable rates of adverse events to initial treatment with AADs while offering superior efficacy in rhythm maintenance.^3,4

However, the evidence is less definitive regarding the superiority of first-line catheter ablation over AADs in persistent AF, with further research needed to clarify its relative benefits in this subset of patients and the best technique to reduce recurrence.

Early ablation seems to reduce the progression of AF; however, the exact timing is still unclear.⁵ However, a small RCT examined the impact of delaying ablation in patients with paroxysmal or persistent AF by 12 months while optimizing medical therapy, compared with performing ablation within 1 month.⁶ The findings suggested that a delayed approach did not compromise arrhythmia-free survival, indicating that ablation can be effectively performed after an initial period of medical management without negatively affecting long-term outcomes.

Patients with heart failure

AF catheter ablation is recommended in patients with AF and heart failure (HF) with reduced ejection fraction (HFrEF) with a high probability of tachycardia-induced cardiomyopathy to reverse left ventricular dysfunction.

Class I Evidence B

AF catheter ablation should be considered in selected AF patients with HFrEF to reduce HF hospitalization and prolong survival.

Class IIa Level B

Randomized trials have consistently shown that catheter ablation for atrial AF in patients with HFrEF significantly decreases arrhythmia recurrence and enhances left ventricular ejection fraction. These improvements are often accompanied by better clinical outcomes, including reduced symptoms, fewer hospitalizations, and, in selected cases, lower mortality rates.⁷

A growing body of evidence highlights the benefits of maintaining sinus rhythm in patients with both AF and HF while avoiding the long-term use of AADs such as amiodarone. This strategy has been shown to improve left ventricular function, alleviate symptoms, and reduce hospitalization rates, ultimately contributing to decreased mortality. Catheter ablation, by facilitating the restoration and maintenance of sinus rhythm, represents a crucial therapeutic option to reduce the burden of prolonged use of AADs and should be considered a key component of HF management in this population along with optimal medical therapy.

To optimize outcomes from catheter ablation in patients with HFrEF, careful patient selection is essential. Several factors, including the type of AF (paroxysmal vs. persistent), the extent of left atrial dilatation, and the presence of atrial and/or ventricular fibrosis, can help identify patients most likely to benefit from the procedure. Tailoring the intervention based on these characteristics can maximize the clinical advantages and ensure more favourable results for patients with HFrEF undergoing AF catheter ablation.⁷

Patients with atrial fibrillation-related bradycardia or sinus pauses on atrial fibrillation termination

AF catheter ablation should be considered in patients with AF-related bradycardia or sinus pauses on AF termination to improve symptoms and avoid pacemaker implantation.

Class IIa Level C

Catheter ablation can be a valuable treatment option for patients who experience symptoms related to prolonged pauses following the termination of AF. In such cases, non-randomized studies have demonstrated that this intervention can lead to significant symptomatic improvement.⁸ Additionally, catheter ablation may help patients avoid the need for pacemaker implantation, which is often considered in managing such pauses. By targeting and modifying the areas responsible for arrhythmia, catheter ablation addresses the underlying cause of the pauses, providing both clinical relief and a potential alternative to more invasive or permanent solutions like pacemakers.

Repeat atrial fibrillation catheter ablation

Repeat AF catheter ablation should be considered in patients with AF recurrence after initial catheter ablation, provided the patient’s symptoms were improved after the initial pulmonary vein isolation (PVI) or after failed initial PVI, to reduce symptoms, recurrence, and progression of AF.

Class IIa Level B

Repeat AF catheter ablation should be considered for patients experiencing AF recurrence following an initial catheter ablation, especially if the patient demonstrated symptomatic improvement after the initial PVI or if the initial PVI was unsuccessful. This approach aims to further reduce symptoms, minimize AF recurrence, and prevent disease progression. The decision to proceed with a repeat ablation should be guided by shared decision-making, ensuring that the patient is actively involved in the process. Clear treatment goals should be established, focusing on optimizing symptom control and improving overall quality of life.

Zhang’s 2024 randomized trial evaluated the effectiveness of catheter ablation vs. AADs for managing recurrent atrial tachycardia (AT) following persistent AF ablation. The findings underscore the superiority of catheter ablation over AADs in sustaining sinus rhythm, ensuring long-term safety, and improving quality of life (QoL) in this patient population. However, the adoption of catheter ablation may be constrained by an elevated risk of peri-procedural complications.⁹

Anticoagulation in patients undergoing catheter ablation

Initiation of oral anticoagulation (OAC) is recommended at least 3 weeks prior to catheter-based ablation in AF patients at elevated thromboembolic risk, to prevent peri-procedural ischaemic stroke and thromboembolism.

Class I Level C

Uninterrupted OAC is recommended in patients undergoing AF catheter ablation to prevent peri-procedural ischaemic stroke and thromboembolism.

Class I Level A

Continuation of OAC is recommended for at least 2 months after AF ablation in all patients, irrespective of rhythm outcome or CHA2DS2-VA score, to reduce the risk of peri-procedural ischaemic stroke and thromboembolism.

Class I Level C

Continuation of OAC is recommended after AF ablation according to the patient’s CHA2DS2-VA score, and not the perceived success of the ablation procedure, to prevent ischaemic stroke and thromboembolism.

Class I Level C

Cardiac imaging should be considered prior to catheter ablation of AF in patients at high risk of ischaemic stroke and thromboembolism despite taking OAC to exclude thrombus.

Class IIa Level C

This task force recommends that clinicians use the CHA₂DS₂-VA score, rather than CHA₂DS₂-VASc, to guide decisions on OAC therapy. This adjustment removes the criterion for birth sex, as female sex does not independently increase stroke risk but instead serves as an age-dependent risk modifier.¹⁰

For patients with AF undergoing catheter ablation, the presence of a thrombus in the left atrial appendage is a contraindication. Therefore, for individuals at high thromboembolic risk, at least 3 weeks of anticoagulation therapy is recommended prior to the procedure.¹¹ Imaging should also be used to exclude the presence of thrombus before proceeding with the ablation since the presence of thrombosis in high-risk patients, despite congruous anticoagulation regimen, may be up to 2.7%.¹²

Post-procedure, continuation of OAC is advised for at least 2 months for all patients and indefinitely for those at high thromboembolic risk, regardless of the ablation’s success.¹¹

These recommendations are largely based on EO, emphasizing the urgent need for more robust clinical trials in this field.

On the other hand, the use of uninterrupted direct oral anticoagulants (DOACs) during the peri-procedural period is demonstrated by multiple RCTs supporting a level of Evidence (LOE) A.¹³

What is new and what is missing

Despite a large body of literature published in the last 4 years about AF ablation, there are only a few updates in 2024 GLs¹ compared with 2020 GLs.²

1. Based on robust RCTs, recommendations for AF ablation already considered a Class I indication passed from a LOE B to a LOE A.¹

2. A new indication for AF ablation to avoid pacemaker implantation in patients with AF-related bradycardia or sinus pauses on AF termination has been introduced. This recommendation, however, is based on expert consensus rather than RCTs.^3,4

3. The GLs now include a new recommendation for redo procedures in symptomatic patients who have undergone prior ablation. This update is supported by emerging data, even though some studies report discrepancies in the extent to which repeat ablation significantly reduces AT/AF recurrence rates.^9,14

4. Uninterrupted OAC is advised for patients undergoing AF catheter ablation to reduce the risk of peri-procedural ischaemic stroke and thromboembolism.¹³

5. The CHA₂DS₂-VA score is recommended for thromboembolic risk stratification rather than CHA₂DS₂-VASc dropping the stratification by gender.¹⁰

Professional society GLs are periodically updated to reflect advancements in the field. However, the current methodology for these updates inherently introduces a delay, preventing the GLs from incorporating new, practice-changing evidence in a timely manner. This latency arises from the structured and often lengthy processes involved in reviewing, evaluating, and formally adopting updates.

Although a significant amount of literature has been published on AF ablation utilizing various energy sources including radiofrequency, cryoablation,¹⁵ and the more recently introduced pulsed field ablation,¹⁶ the current GLs do not express a clear preference or provide specific indications for any particular technique.

Currently, there are no definitive recommendations regarding the optimal technique for the ablation of persistent AF. In the literature, the effectiveness of adjunctive strategies such as posterior wall ablation or adjunctive line,¹⁷ ganglionated plexi ablation,¹⁸ and left atrial appendage isolation¹⁹ remains inconclusive or doesn’t provide any benefit. While these methods are often investigated and employed in clinical practice, robust data to establish their routine use or superiority in achieving long-term outcomes are still lacking.

This absence of clear guidance underscores the need for further research and well-designed randomized trials to better define the role of these techniques and to identify the most effective strategies for both paroxysmal and persistent AF ablation.

Original meaning of guidelines in clinical medicine and deviations with time

Thirty years ago, the Institute of Medicine initiated efforts to advance the development of clinical GLs with the aim of enhancing the quality of healthcare delivery and improving patient outcomes. Their aim is to outline evidence-based strategies for the diagnosis, treatment, and prevention of specific diseases or conditions, based on a meticulous and systematic analysis of the highest-quality scientific research available.

To fill the gaps left by lack of RCTs in some aspect of managing patients with AF, indications based on EO found their place in GL recommendation.

Over time, these robust methodologies for developing clinical GLs stratifying the recommendations in Class I (it’s recommended), IIa, (should be considered: the weight of evidence and EO favours the intervention’s usefulness), IIb (may be considered: the usefulness of the intervention is less well established based on the weight of evidence and EO), and III (it’s not recommended) become widely recognized. This classification is underpinned by evidence-based medicine, which serves as the foundation for determining the LOE.

LOE A is characterized by the highest-quality evidence, typically derived from multiple RCTs, meta-analyses of RCTs, or a combination of one or more RCTs supported by high-quality registry studies.

LOE B is based on moderate-quality evidence, which may come from a single RCT, meta-analyses of moderate-quality RCTs, or studies with limitations. Evidence at this level is further subdivided into randomized (B-R) or non-randomized (B-NR) evidence, reflecting the study design.

LOE C limited data (LD) refer to LD, typically from observational studies, non-randomized trials, or registry studies that have notable design or execution limitations. Meta-analyses of such studies also fall under this category.

LOE C EO is based entirely on EO, often used when empirical data are unavailable or insufficient.

Despite GLs consistently emphasizing that clinical decision-making should prioritize higher LOE whenever possible, ensuring that patient care is rooted in the most reliable data. However, the reliance on LOE B and C has drawn criticism. These levels, often reflecting less robust data or subjective judgment, are seen as more susceptible to bias.

Gradually, indication based on EO became prevalent among other indications.

In the ESC 2024 GLs, out of 137 recommendations, the percentage of indications with LOE A was only 20% while LOE C was almost one-third of the indications.¹

This limitation underscores the need for ongoing improvement in guideline methodologies, striving to minimize the use of lower-quality evidence and to enhance the reliability and validity of clinical recommendations.

In today’s world, rapid technological advancements are driving significant progress in science and communication. As a result, GLs, even when based on high-quality scientific research, can quickly become obsolete. This makes it inevitable that the current approaches to developing GLs will need to be reassessed and updated in the future.

A novel model for guideline production where recommendations are not influenced by arbitrarily introduced methods of judgement, including sub-categorization (IIa and IIb), sub-classification (level of Evidence A, B, and C), and consensuses among experts

The European Cardiac Arrhythmias Society (ECAS) is adopting a new methodology for the creation of its guideline documents.²⁰ This approach aims to enhance the rigour and transparency of the guideline. The primary motivation behind this initiative is to deliver GLs that are more concise and accessible for day-to-day practice and that reflect evidence-based data behind the indications.

Departing from traditional formats, the ECAS proposes a paradigm shift by omitting the commonly used LOE classifications that clinicians are accustomed to seeing. Instead, the writing group will simplify recommendations by categorizing them into three distinct classes: I, II, and III eliminating the sub-categorizations IIa and IIb. Although the LOE will no longer be explicitly stated, it will remain an implicit part of the recommendations. This simplified approach reflects a deliberate choice to focus on clarity and utility, rather than adhering to previous conventions.

Moreover, the authors of this methodology recognize the historical importance of explicitly including LOE, as seen in GLs from other societies, but have decided to exclude LOE C based solely on EO, further underscoring their commitment to a more evidence-focused and practical framework.

Under their proposed methodology for catheter ablation GLs, the ECAS delineates recommendations into three classes based on the strength and quality of evidence.

Class I recommendations indicate practices, strategies, or techniques in catheter ablation that are strongly endorsed due to compelling evidence of greater benefit than risk. These recommendations are grounded in high-quality, multicentre RCTs that adhere to pre-determined working hypotheses and are backed by sufficient sample sizes. Such robust evidence ensures a high degree of confidence in the safety and efficacy of the recommended approaches.

Class II recommendations indicate catheter ablation practices or specific strategies where evidence suggests a greater benefit than risk, but this evidence is not derived from high-quality, multicentre RCTs. These recommendations reflect scenarios where rigourous randomized trials may be unavailable but other forms of evidence—such as observational studies and smaller-scale trials—support the clinical value of the approach. This category acknowledges the necessity of providing clinicians with guidance even in the absence of strong evidence, ensuring patient care is informed by the best available data.

Class III recommendations indicate practices, strategies, or techniques in catheter ablation that should not be undertaken. These recommendations are based on high-quality, multicentre RCTs that clearly demonstrate no benefit or a greater risk of harm compared with alternatives. This category serves to caution clinicians against interventions that are unlikely to achieve desired outcomes or could compromise patient safety.

This tiered approach integrates the LOE directly into the class of recommendation, offering a significant advantage by simplifying the presentation of recommendations. This simplicity enhances the practical adoption of GLs in clinical practice, as it minimizes complexity while retaining essential information. By embedding the evidentiary strength within the recommendation itself, clinicians can more easily interpret and apply these GLs in real-world scenarios, potentially increasing their implementation and impact.

Any gaps in knowledge are not considered a deficiency of the guideline methodology itself but rather an inherent limitation of current clinical investigations. Such gaps underscore the need for continued research to address unanswered questions and refine clinical understanding. The authors highlight their role in identifying areas where evidence is insufficient, providing a roadmap for future research.

By encouraging well-designed clinical trials to address these gaps, this methodology aims to foster a cycle of continuous improvement in evidence-based care.

Summary and future directions

In conclusion, this paper highlights why there was a necessity for an update of the ESC 2020 GLs,² describes what’s new in the 2024 GLs¹ about AF ablation, and suggests possible future directions on editing GLs.

Despite multiple relevant changes that have been introduced in the 2024 document, only a few updates have been made about catheter ablation.

Indications about sources of energy and adjunctive strategy beyond pulmonary vein ablation are lacking, creating a discrepancy between the GL recommendation and procedure performed in the real world.

To address the limitations of current ESC guideline editing methods, the ECAS proposes an alternative approach grounded entirely in evidence-based medicine.²⁰ This strategy aligns with practices already adopted by other scientific societies and operates on the premise that future developments could introduce new paradigms, theories, investigative methods, and validation techniques that might redefine the current structure of GLs.

Funding

No funding provided.

Data availability

No new data were generated or analysed in support of this research.

Disclaimer

This paper was originally published in the Volume degli Atti del Congresso “Conoscere e Cuare il Cuore 2025” by Centro per la Lotta contro l'Infarto for distribution at the CCC Conference. This paper is republished with permission.

References

Author notes