July 28, 2015
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Minimal, maximal pulmonary vein isolation yield similar freedom from AF

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Freedom from atrial fibrillation occurred at similar rates between minimal and maximal pulmonary vein isolation strategies, according to results from the MINIMAX study.

However, patients in whom antral isolation can be achieved without intervenous ridge ablation had higher long-term freedom from AF, the researchers wrote.

Alex J.A. McLellan, MBBS, and colleagues compared outcomes from a minimal strategy (circumferential antral pulmonary vein isolation alone) with a maximal strategy (circumferential antral pulmonary vein isolation with intervenous ridge ablation) in 234 patients with paroxysmal AF (mean age, 59 years; 66% men). They used 7-day Holter monitoring to assess the primary outcome, recurrent atrial arrhythmia, at 6 and 12 months.

McLellan, from Alfred Heart Centre, Alfred Hospital, Melbourne, Australia, and colleagues reported that pulmonary vein isolation was achieved in all patients with no significant difference in procedural or fluoroscopy times between the groups. However, radiofrequency ablation time was longer in the maximal group (46.6 minutes vs. 41.5 minutes; P < .01).

After a mean follow-up of 17 months, there was no difference between the groups after a single procedure with regard to freedom from AF (minimal, 70%; maximal, 62%; P = .25), according to the researchers.

Within the minimal group, 44% of patients required ablation on the intervenous ridge to achieve isolation. Compared with those in the minimal group who did not require it, these patients were less likely to achieve freedom from AF (57% vs. 80%; P < .01), McLellan and colleagues wrote.

“These findings may be explained by patients with unfavorable anatomy such as more complex connections at the [intervenous ridge] or inadequate contact force at the antral ring to achieve acute and enduring [pulmonary vein isolation] with an antral approach,” they wrote.

In a related editorial, Lluís Mont, MD, PhD, wrote that, “We are probably entering an era of minimalism in the field, reintroducing the concept that ‘less is more.’”

Mont, from the department of cardiology, arrhythmia section, Thorax Institute-Hospital Clinic, University of Barcelona, wrote that, “Despite all the accumulated experience, we still lack enough information to personalize ablation in each individual, which could result in more efficacious and less extensive ablations in some patients. … Meanwhile, a ‘minimalist’ approach based on effective [pulmonary vein] isolation seems advisable in most patients, reserving more extensive ablations for specific patients with very enlarged atria, extensive fibrosis or long-standing persistent AF, recognizing that even in the best hands, the success rate in such patients with be limited.” – by Erik Swain

Disclosure: One researcher reports financial ties with Biosense Webster, Biotronik, Boston Scientific, Medtronic, Merck Sharpe & Dohme, Sanofi-Aventis, Sorin and St. Jude Medical. Mont reports no relevant financial disclosures.