AF ablation procedures have become too complex: simple is best

The simple approach is usually best when it comes to ablation treatment of persistent atrial fibrillation, according to a study that  found no additional benefit from MRI-guided fibrosis ablation in preventing recurrence.

An international study including Australian centres found that using the advanced image-guided technology to more aggressively target atrial fibrosis didn’t lead to better outcomes for patients over pulmonary vein isolation (PVI) catheter ablation only.

The DECAAF II trial published in JAMA involved 843 AF patients undergoing ablation treatment at 44 hospitals in 10 countries.  All patients underwent delayed-enhancement MRI before the ablation procedure to assess baseline atrial fibrosis and at three months postablation to assess for ablation scar.

Participants were then randomly assigned to pulmonary vein isolation (PVI) plus MRI-guided atrial fibrosis ablation (421 patients) or PVI alone (422 patients).

After a follow-up period of 12 to 18 months, there was no significant difference between groups in AF recurrence (43.0% for fibrosis-guided ablation plus PVI vs 46.1% for PVI-only patients).

Patients in the fibrosis-guided ablation plus PVI group experienced a higher rate of adverse outcomes (2.2% vs 0 in PVI group). Six patients (1.5%) in the fibrosis-guided ablation plus PVI group had an ischaemic stroke compared with none in PVI-only group. Two deaths occurred in the fibrosis-guided ablation plus PVI group, and the first one was possibly related to the procedure.

Study author Dr Nassir Marrouche, director of the Tulane Heart and Vascular Institute and The Research Innovation for Arrhythmia Discoveries (TRIAD) said that the study showed that AF patients with extensive fibrosis have too much scarring for aggressive ablative therapy to be effective using conventional tools.

“Simplicity is key. Don’t ablate too much, especially at advanced stages,” he said

“Too much ablation is not helping our patients today. It is putting them at higher risk. This is a practice-changing finding from our study.”

The authors of the study said the lack of benefit of fibrosis-guided ablation could be explained by several factors related to technical challenges and the pathophysiology of AF.

They noted that the mechanism by which fibrosis leads to initiation or perpetuation of AF is still not completely understood, with different types of fibrosis co-existing in atrial tissue contributing unequally to AF development.

“The arrhythmogenic propensity of fibrotic tissue can depend on the texture and spatial distribution of fibrosis. While not all fibrosis plays an active role in AF, current imaging techniques cannot make the distinction, limiting the benefit of extensively ablating fibrotic tissue,” they wrote.

Also, the lack of uniformity in how clinicians perform ablation interventions may lead to disparate outcomes through variation in targeting strategies and use of inconsistent endpoints, they added.

“Atrial fibrillation procedures have become too complex over the years. We are ablating hundreds of thousands of people a year now, and we have been striving to do more and more ablation for the population with persistent or continuous AFib,” said Dr Marrouche.

“But our study shows that isn’t necessary, especially for those with more myopathy. Simple ablations can effectively treat these patients instead of going for extensive ablation to treat fibrotic areas that we struggle to control.”

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