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An updated expert consensus statement on catheter and surgical ablation of atrial fibrillation (AF) has been issued after a collaboration involving four cardiac electrophysiology societies.

This consensus is a joint effort from the European Heart Rhythm Association (EHRA), Heart Rhythm Society, Asia Pacific Heart Rhythm Society, and Latin American Heart Rhythm Society.

"Catheter ablation is a very important tool in our armamentarium against AF," lead author of the statement and EHRA Chair Stylianos Tzeis, MD, Mitera Hospital, Athens, Greece, told theheart.org | Medscape Cardiology.

This consensus statement represents clinical advice rather than guidelines and is a new update of the consensus document originally published in 2007 with revisions in 2012 and 2017, he noted.

"There have been many technical advancements and development of new tools and new ablation strategies in recent years, so we need to update this consensus document again and reshape the contemporary framework for catheter and surgical AF ablation," Tzeis said.

The consensus was put together by a committee comprising 43 members of the four electrophysiology societies.

"We are aiming to provide practical advice to help practicing clinicians and electrophysiologists to optimize processes for the selection and interventional management of patients," Tzeis stated.

This consensus statement has been co-published in full in EP Europace, Heart Rhythm, Journal of Arrhythmia, and Journal of Interventional Cardiac Electrophysiology.

The current updated consensus document has a new structure and incorporates five new sections that reflect the different stages of patient management: Indications, preprocedural management, ablation strategies, procedural management, and post-procedure management.

Indications

Regarding indications for catheter ablation, one major change in this document is upgraded advice for the use of this technology as a first-line treatment for patients with symptomatic paroxysmal AF.

Tzeis explained that previously, catheter ablation has been used mainly for patients with paroxysmal AF who have already tried or who were intolerant to antiarrhythmic medical treatments, but now, the consensus statement is recommending catheter ablation even in patients who have not tried other treatments. This is based on several randomized clinical trials that have shown superior efficacy and similar safety with catheter ablation when implemented as first-line therapy in patients with symptomatic paroxysmal AF.

Tzeis pointed out that this advice does not apply to patients with persistent AF. "For persistent AF there is a grey zone — we need more data. We don't have enough data to support use of catheter ablation for first-line treatment in this group. However, we suggest that catheter ablation can be used in persistent AF patients who have already tried antiarrhythmic agents," he noted.

The consensus document has also upgraded the role of catheter ablation in selected patients with AF and heart failure with systolic dysfunction to improve left ventricular systolic dysfunction but only for patients in whom it is suspected that AF is the cause of the systolic dysfunction.

"In these patients, we suggest catheter ablation can be used with the highest level of clinical advice. But the key issue here is the 'selected.' We need to work to develop and validate approaches to identify subgroups of patients with AF and heart failure who will have a favorable response to AF ablation," Tzeis commented.

Pre-Procedure Management

A key part of preprocedural management is the exclusion of thrombus in patients scheduled for catheter ablation, and the new consensus document has upgraded the role of intracardiac echocardiography for this purpose.

"The presence of thrombus is a contraindication for catheter ablation. This is extremely important because thrombus is the main reason for many of the most frequent complications of AF — thromboembolic events such as stroke. If there is a preexistent thrombus, the ablation process could dislodge the thrombus and cause a stroke," Tzeis explained.

The vast majority of patients should have already received preprocedural treatment with anticoagulants. But if this is not the case, then they need to be screened for exclusion of thrombus.

The statement has advised that it is reasonable to perform imaging for the exclusion of thrombus in several patient groups.

These include patients eligible for anticoagulation but who have not yet received anticoagulation therapy for 3 weeks or longer. In addition, the authors recommended screening for thrombus may be reasonable even in patients who have received adequate anticoagulation therapy for 3 weeks or longer in the presence of specific factors that are associated with thrombus risk, for example, increased CHA2DS2-VASc score (3 or above), patients with non-paroxysmal AF, and those with hypertrophic cardiomyopathy, cardiac amyloidosis, or rheumatic heart disease.

On the types of imaging that can be used, the statement suggests that transesophageal echocardiography, cardiac CT, and intracardiac echocardiography are all reasonable imaging options to exclude the presence of thrombus, and the selection of a specific imaging tool should be based on different factors including patient characteristics, physicians' expertise, and availability of the various imaging modalities at the institution.

Specific Ablation Strategies

Regarding ablation strategies, the consensus document emphasizes that pulmonary vein isolation (PVI) — the favored technique for the last two decades — is still the gold standard and the cornerstone for all types of AF ablation.

"This is an area in which we have not made major progress," Tzeis said. "This stems from the fact that most randomized trials trying to test different ablation strategies have not shown positive results."

He noted that the EP community is searching for other techniques that may be added to PVI in order to reap an additional benefit in challenging cases such as patients with persistent AF.

"In patients with paroxysmal AF, we rely simply on PVI. In persistent AF, we do PVI, and we still have not clarified which adjunctive strategy may have additional benefit on top of PVI," he explained.

"One change in this update is that we have recommended not to perform some kind of additional ablation strategy based on the use of MRI to identify fibrotic areas of the atria. This is because randomized trial results have shown significantly more complications with this approach. But we have left a small door open so that there might be an option for future trials to test other protocols using MRI," Tzeis reported.

Other options for adjunctive ablation strategies include the ablation of areas of abnormal myocardial tissue identified with voltage mapping during sinus rhythm, ethanol infusion in the vein of Marshal, and isolation of the left atrial posterior wall.

"All these options only apply to persistent AF, and we cannot provide clear guidance on when these strategies could be tried as there are conflicting data, and we do not have consistent positive findings. We are in need of further randomized trials to look at these strategies and try to get clearer data." Tzeis stated.

He emphasized that in paroxysmal AF, the only ablation strategy performed should be PVI.

Procedural Management

The major change in terms of procedural management is strong advice in favor of the use of intracardiac echocardiography for the exclusion of thrombus.

The statement also strongly advises the use of ultrasound to gain vascular access in the groin.

"We now have strong data to show that this approach significantly reduces the risk of vascular complications, which remain the most frequent adverse effect of catheter ablation," Tzeis said. "We have an easy inexpensive way of preventing this complication, and ultrasound-guided vascular access should therefore be performed in every lab. And this should be adopted irrespective of the experience of the operator."

The statement has also downgraded the role of esophageal temperature monitoring. This had been proposed in a previous guideline to prevent esophageal perforation. But new clinical trials have now shown that esophageal temperature monitoring does not seem to provide substantial benefit and does not result in a reduced risk for endoscopically detected esophageal lesions, Tzeis noted.

Postprocedural Management

Post-procedure recommendations are focused on the use of anticoagulation and antiarrhythmic agents after the procedure.

Tzeis stresses that the use of anticoagulation after catheter ablation is of "crucial importance," with different recommendations for different patients and timeframes.

There are two distinct time periods to be considered — the early postprocedural period (the first 2 months) and the late postprocedural period (2 months onward).

In the early postprocedural period, anticoagulation is recommended for all patients regardless of thromboembolic risk and CHA2DS2-VASc score.

But Tzeis noted that it was not so easy to reach a consensus for the late postprocedural period because of the lack of high-quality randomized data.

They authors concluded that in low-risk patients (CHA2DS2-VASc score 0 in men and 1 in women), anticoagulation can be discontinued 2 months after catheter ablation regardless of ablation outcomes.

In the intermediate-risk patients (CHA2DS2-VASc score of 1 in men and 2 in women), discontinuation of anticoagulation can be considered at 12 months following catheter ablation in the absence of symptoms or ECG-documented AF. But to maximize safety, patients and physicians must be committed to long-term screening for AF, which can guide whether reinitiation of anticoagulation is required.

In high-risk patients (CHA2DS2-VASc score of 2+ in men or 3+ in women), anticoagulation should not be discontinued. However, if the patients have a strong preference to stop anticoagulation even after explaining to them that this would incur increased risk, then they should be given regular monitoring to screen for AF recurrence, Tzeis said.

In terms of antiarrhythmic drugs, the only reason to use these is to prevent the early AF recurrences — within 3 months — and they don't seem to prevent longer term AF recurrence, Tzeis noted.

"We do not routinely administer antiarrhythmic agents, and when we do, it is only really in patients with persistent AF who have tolerated antiarrhythmic agents well in the past," he added.

Future Aims

Regarding future aims, the consensus authors have recommended a major change that will be important for future clinical trial design.

This involves the length of the blanking period — an initial period following ablation in which if an AF recurrence occurs it is not considered a treatment failure.

"If a patient has a recurrence of AF in that period, it doesn't mean the ablation hasn't worked, as in this initial period, arrhythmia may occur because of inflammation or because of reversible changes that occur in the myocardium," Tzeis explained. "The earlier these recurrences occur the less likely they are indicative of treatment failure."

The consensus statement notes that new strong data that have shown this blanking period — which used to be 3 months — should be shortened, and it has now been established that the optimal duration of this period is now 8 weeks.

"So, we strongly suggest that upcoming clinical trials should be designed with a blanking period of 8 weeks," Tzeis said.

Definition of AF Recurrence

Finally, on clinical trial endpoints, the statement strongly recommends that the AF burden is reported.

"We believe it is very important to move away from the concept of defining the outcome after ablation in a binary mode — successful or unsuccessful," Tzeis commented.

"In a clinical setting, it is the quantification of the arrhythmia that is important. We strongly suggest AF burden before and after ablation is reported, and the difference is used as a relevant outcome."

But he pointed out that this should not be the primary endpoint.

"We still encourage use of arrhythmia duration as the primary endpoint based on the current 30-second limit. This has major limitations, but unfortunately, we have not yet got strong data that allows us to define the duration of a recurrence that is indicative of a prognostic outcome."

Tzeis noted that new data have suggested that a 1-hour AF duration was associated with impaired AF-related quality of life and increased healthcare utilization, but this is not adequate to formulate guidelines on relevant primary endpoints for clinical trials.

"There is a huge difference between arrhythmia durations of 30 seconds and 1 hour, and at the end of the day, we must not forget that the aim of this treatment is to alleviate patients' symptoms. Someone may have a recurrence of 1 minute and that may be symptomatic, so needs to be considered as important."

He added that clinicians try to rely on both symptoms and AF detected by monitoring.

"In a routine clinical setting, we tend to rely more on patient symptoms. But in a clinical trial setting, we need to have a more consistent and well-defined monitoring protocol and endpoints that will also allow comparison with previous trials."

On the most important areas for the focus of future research, Tzeis said these included gaining more information on additional ablation strategies other than just PVI, describing this as "a million-dollar question."

He believes another big aim is the development and validation of phenotype mapping tools that will identify the kind of patient with heart failure and AF who will gain benefit from catheter ablation. "We need to know how to cherry-pick the optimal candidate in the pool of millions of patients with heart failure and AF that will improve their prognosis by performing these invasive treatments."

Tzeis said the whole field of catheter ablation is expanding rapidly.

"We expect to have much more data in the next few years. The armamentarium is enriching, our experience is growing, and we are hopeful for a lot more positive findings," he concluded.