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BARCELONA -- Doing more radiofrequency ablation for persistent atrial fibrillation (Afib) beyond pulmonary vein isolation doesn't improve outcomes and takes longer, with more radiation exposure, researchers reported here.

In the STAR-AF2 trial, the primary endpoint of freedom from recurrence of Afib at 18 months wasn't significantly different between three groups, although it was numerically higher among patients who had pulmonary vein isolation ablation alone, , of Southlake Regional Health Center in Newmarket in Canada, and colleagues reported at the European Society of Cardiology meeting.

Both treatment time and fluoroscopy exposure were significantly longer in those who had more involved procedures as well, Verma reported.

"This should give us pause for doing more extensive procedures, especially if it's not offering any benefits for the patients," Verma told reporters during a press briefing, adding that theirs was the largest randomized trial to examine the outcomes of catheter ablation in persistent Afib, outcomes better characterized in paroxysmal Afib.

Verma said he believed the findings would change practice, since current guidelines suggest more extensive ablation than just the pulmonary veins alone. Instead, the focus should shift to shorter and more effective pulmonary vein ablation alone without other ablation, he said.

For their trial, they enrolled 589 patients with persistent Afib, who were randomized to one of three groups: pulmonary vein ablation alone, ablating the pulmonary vein as well as atrial regions of the heart that produce abnormal electrograms, or pulmonary vein ablation plus ablation of linear lesions in the left atrium.

Most of the patients (76%) had experienced continuous Afib for at least 6 months before getting the therapy.

Overall, the researchers saw a 97% success rate, but the primary endpoint of freedom from recurrence of Afib either with or without anti-arrhythmic medication at 18 months wasn't significantly different between the three groups (59% and 48% and 44%, P=0.15).

Rates of the primary endpoint were also similar between groups when looking only at patients who did not need anti-arrhythmia drugs (48%, 37%, and 33%, P=0.11).

The procedural time was significantly shorter for pulmonary vein ablation alone compared with pulmonary vein plus electrogram findings and pulmonary vein plus linear lesions (167 mins versus 229 and 223 mins, P<0.0001).

These two groups also had significantly longer fluoroscopy exposure (29 mins versus 42 and 41 mins, P=0.0003).

"In spite of these procedures taking longer, they offered absolutely no increased benefits over the more minimal approaches," Verma said.

Overall rates of serious adverse events, including cardiac tamponade and stoke, were very low -- among the lowest reported for any multicenter trial to date, Verma said.

But he cautioned that there were generally more adverse events in the two groups that involved more extensive procedures. He called attention to an atrial esophageal fistula leading to procedural death that occurred in the pulmonary vein ablation plus electrogram findings group.

Verma concluded that performing additional -- perhaps unnecessary -- ablation has the potential to increase risk, and that clinicians should rethink performing more extensive ablation.

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