\u201cThe issue with microsecond [pulsed field ablation] is that it certainly works, but our durability is not as high as we\u2019d like it to be. So we want to have more intense ablation of lesions to improve our outcomes,\u201d he told Healio. \u201cThe problem with that is that already it\u2019s becoming clear that there are some near-field effects that can happen. And those near-field thermal effects can have an important impact in terms of potential clot and stroke. What nanosecond does is by shortening the duration of each of these impulses, you can basically push the output so you can increase the voltage. With microsecond, you could increase the voltage, but you\u2019d just get too much heating because you\u2019re dumping a lot of energy into the tissue. With nanosecond, you can get up over 10,000 volts compared to microsecond, which is around 2,000, and still not get any appreciable heating.\u201d<\/p>\n
Nanosecond pulsed field ablation<\/h2>\n For the first-in-human study, simultaneously published in JACC: Clinical Electrophysiology<\/i>, Reddy and colleagues performed nanosecond pulsed field ablation on 177 patients with paroxysmal AF (mean age, 61 years; 36% women). All patients had pulmonary vein isolation using 2.5-second or 5-second applications, and some also had ablation at the posterior wall, cavotricuspid isthmus or mitral isthmus. Lesion durability was assessed via invasive remapping at 2 to 3 months. Patients received transtelephonic and Holter monitoring at 6 months and 1 year. <\/p>\n
Acute success occurred in 100% of lesions, the mean pulmonary vein isolation time was 12 minutes, the mean total left atrial dwell time was 19 minutes, the mean procedure time was 65 minutes, and the mean fluoroscopy time was 9 minutes, according to the researchers.<\/p>\n
There were three serious adverse events, for a rate of 1.7%: one patient had inflammatory pericardial effusion, one had hemolysis with acute kidney injury, and one had a stroke, the researchers reported.<\/p>\n
The patient with hemolysis \u201chappened relatively early in our experience,\u201d Reddy told Healio. \u201cSince then, we\u2019ve not had any other such dialysis incidents because we now know to hydrate the patients, but that\u2019s still an important complication.\u201d <\/p>\n
Among the 35 patients who had a brain MRI, 11.4% had silent cerebral events and 11.4% had silent cerebral lesions, according to the researchers. <\/p>\n
\u201cThat\u2019s on the low end of what we see with most of these technologies,\u201d Reddy told Healio. <\/p>\n
At 2 to 3 months, the durability of the procedure with 5-second applications was 91%, and at 1 year, the estimated rate of freedom from atrial arrhythmias was 89.7% (95% CI, 80.5%-94.6%), Reddy and colleagues found. <\/p>\n
\u2018The patients did … quite well\u2019<\/h2>\n The durable isolation rate of 91% \u201cis actually quite good,\u201d Reddy said. \u201cObviously, I\u2019d like it to be even higher, but given that we had seven different operators at three different centers, I feel pretty good about that.\u201d <\/p>\n
A limitation of the study is that the patients did not have implantable loop recorders, so asymptomatic arrhythmias could have gone undetected, Reddy said. <\/p>\n
\u201cThe rate of 1-year freedom from arrhythmias was pretty impressive,\u201d he told Healio. \u201cThese patients did not have implantable loop recorders, so you can\u2019t take this too far, but the fact is that the patients did seem to do quite well. The idea of nanosecond [pulsed field ablation] works.\u201d <\/p>\n
A pivotal trial of the technology just started enrolling, he said. The system is not yet approved for commercial use in the United States. <\/p>\n
For more information:<\/h2>\n Vivek Y. Reddy, MD, <\/b>can be reached at vivek.reddy@mountsinai.org.<\/p>\n\n
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Perspective<\/h2>\n Back to Top
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There is the potential to deliver higher voltage to the tissue in shorter duration, which may achieve a deeper lesion and cause less stimulation of the skeletal muscles. One of the major limitations of pulsed field ablation is that it typically requires deep sedation and\/or paralytics, and this has the ability to change anesthesia requirements.<\/default:p>It is clear that we have many new companies that are developing the second generation of pulsed field ablation catheters to make it safer and more effective. The durability in this study appears promising and is novel, as many studies do not require remapping to assess this important endpoint.<\/default:p><\/p>\n\n
Roderick H. Tung, MD<\/strong><\/p>\n Director, Cardiovascular Center
Disclosures: <\/strong> Tung reports no relevant financial disclosures.
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Published by:<\/span>\n
Sources\/Disclosures<\/h3>\n Source: <\/h2>\n Reddy VY, et al. Late-breaking clinical trials: Pulsed field ablation. Presented at: Heart Rhythm 2026; April 23-26, 2026; Chicago. <\/p>\n
Reference:<\/h2>\n\n
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