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NEW ORLEANS -- A new atrial fibrillation (Afib; AF) technology -- pulsed field ablation -- appears to eliminate abnormal heart rhythms in most patients for at least a year, a researcher reported here.

In the PULSED AF (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF) trial, 66.2% (95% CI 57.9-73.2) of patients diagnosed with paroxysmal Afib achieved freedom from their bouts of abnormal rhythms at 12 months, as did 55.1% (95% CI 46.7-62.7) of patients who had been diagnosed with persistent Afib, said Atul Verma, MD, chief of cardiology at McGill University Health Centre in Montreal.

Both outcomes were significantly better than the target performance goals of 50% and 40%, respectively (P<0.001 for both), according to findings presented at a press conference at the American College of Cardiology (ACC) annual meeting.

"The efficacy of the procedure is similar to what we see in thermal ablation, but we're getting it much faster and with much more safety," said Verma. "That is a major development for the field of electrophysiology."

Only two primary safety endpoints -- a composite of serious procedure- and device-related adverse events -- occurred, one in each cohort, for a rate of 0.7% (95% CI 0.1-4.6).

Results of the study were simultaneously published online in .

Most pulsed field ablation procedures were completed in less than an hour, Verma said, whereas thermal ablation procedures typically take 2 hours or more. Patients in the study also reported improvements in quality of life, he said.

With pulsed field ablation, Verma explained, lesions are created in cardiac tissue non-thermally through the mechanism of irreversible electroporation. This exposes tissues to high electric field gradients, inducing cell membrane permeabilization within milliseconds, leading to cell death. He suggested the techniques has less risk of damaging surrounding tissues than thermal -- either heat or cold -- ablation techniques.

"Even though this study did not include controls, the results are compelling," Jim Cheung, MD, professor of medicine at Weill Cornell Medicine in New York City and chair of ACC's Electrophysiology Council, told MedPage Today.

"I think there will be a rapid uptake of this therapy, but this is just one pulsed field device and others are in development. I think this is where the field is going to go," he said as designated discussant during the press conference.

"Of course, it is always better to have comparisons," said Cheung, adding that having one of these procedures with one device does not rule out a second ablation with the same device or with other ablation technologies.

The PULSED AF pivotal trial was conducted as a prospective, global, multicenter, nonrandomized, paired single-arm study at 41 sites in Australia and countries across North America and Europe. In total, 150 patients with paroxysmal symptomatic Afib were treated with pulsed field ablation, as were 150 patients with persistent symptomatic Afib who were refractory to class I or III antiarrhythmic drugs.

All patients were monitored for 1 year with weekly and symptomatic transtelephonic monitoring. The patients were given electrocardiograms at 3, 6, and 12 months. They also wore Holter monitors at 6 months and 12 months for 24-hour continuous monitoring.

The primary efficacy endpoint was freedom from a composite of acute procedural failure, arrhythmia recurrence (more than 30 seconds of Afib), or the need for antiarrhythmic escalation through 12 months.

In also commenting on the study, Julia Indik, MD, PhD, professor of medicine at the University of Arizona in Tucson, told MedPage Today that the pulsed field procedure "seems to have a sparing effect on outside architecture of the heart. It seems that the myocardial cells that are most vulnerable are not affected, so this is less collateral damage."

Indik said that anatomically, the goal with pulsed field ablation is the same with thermal ablation -- to isolate the pulmonary vein. She also said that pulsed field applications may be useful in other arrhythmias aside from paroxysmal and persistent Afib.

"Freedom from more than 30 seconds of atrial fibrillation achieved by 55% to 65% of patients in this trial is on par with other technologies," she said.

But that isn't the end of the story.

"This was only a year follow-up, and we would like to know about a longer follow-up," said Indik. "This was also a relatively small study, so we want to see what happens with a larger group of patients. We would like to have more confidence about the safety endpoint."

However, she said, "we are excited about pulsed field ablation because we think that it has the potential to be more efficient and possibly safer. Pulmonary vein ablation at present is very safe, but we still could even improve on that."

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