J&J Halts Varipulse Pulsed-Field Ablation Cases in the US

All ablation cases set to use the Varipulse pulsed-field ablation (PFA) system have been temporarily halted in the United States after four neurovascular events were reported during an external evaluation, device maker Johnson & Johnson Medtech announced Wednesday.

The pause, which was initiated Sunday “out of an abundance of caution,” will allow the manufacturer time to investigate the root cause of the complications.

Johnson & Johnson Medtech noted that because system used in the US External Evaluation study “leveraged a unique platform configuration, there is no impact to commercial activity and Varipulse cases outside of the US.”

The move is a setback for US rollout following Food and Drug Administration approval for Varipulse, which comes with an integrated electroanatomical mapping system, in November 2024. That was supported by the positive results of the pivotal admIRE trial in patients with drug-refractory, symptomatic paroxysmal atrial fibrillation, although the occurrence of two strokes and one TIA in that study was called “somewhat worrisome” by a commentator at the time.

About the pause in Varipulse use, Sumit Verma, MD (Baptist Heart & Vascular Institute, Pensacola, FL), told TCTMD that “many centers such as ours were waiting for this system to start PFA cases. This is a setback for our PFA adoption. We may have to reexplore using one of the other systems.”

For Jonathan Piccini, MD (Duke University Medical Center, Durham, NC), “it is hard to know what to make of the pause in the Varipulse launch here in the US” at this point, he said, noting that in the inspIRE study, “there was a high rate of silent cerebral ischemic lesions before the treatment sequence was redesigned.”

It’s possible, then, that the four neurovascular events reported now could be related to a similar issue, “but that is really speculative at this point,” Piccini told TCTMD. “Whether these events are due to thermal bubbles, electrolysis bubbles, air emboli, thrombus, or another mechanism is not clear and requires further investigation. It is a good reminder that as promising as PFA is, there is still much to learn about the technology and its successful delivery.”

External evaluation of Varipulse in the US—which is “a limited rollout intended to collect physician feedback on a new technology before broader full release,” according to a J&J spokesperson—has included, as of January 3, 2025, more than 130 cases performed across 14 sites by 40 operators.

“Globally, the Varipulse rollout has been successful, with over 3,000 commercial cases completed,” the Johnson & Johnson Medtech said, adding that it is “working diligently to complete the investigation according to our medical safety processes and resume the US External Evaluation.”

It is a good reminder that as promising as PFA is, there is still much to learn about the technology and its successful delivery. Jonathan Piccini

Dhanunjaya Lakkireddy, MD (Kansas City Heart Rhythm Institute and Research Foundation, Overland Park, KS), said his center has been participating in the evaluation, having performed about 25 or 30 cases before the pause, and hasn’t seen any neurovascular issues.

There are a number of reasons a patient may have a stroke during ablation, he said, pointing to the possibility of clots passing from the right to the left side of the heart during transseptal procedures and the potential for air getting introduced with the use of large catheters, such as the PFA catheters, and causing emboli.

In addition, Lakkireddy said, “When you use a large-profile catheter and when you’re trying to ablate a large swath of tissue in a very short period of time, you’re heating up a lot of tissue and maybe there is a possibility that you break down the hematin and that could embolize and cause small strokes.”

And finally, “high-voltage electrical current delivered through these large-profile catheters can generate gas bubbles that can coalesce and form a bigger bubble significant enough to cause embolic events to the brain,” he explained.

Overall, Lakkireddy said he thinks these events are related to the initial experience with centers figuring out how to use the catheter and manage the workflow.

“For any of these catheters that are large profile, if they are not managed properly and the workflow is not well delineated, I think people will get into trouble. This is my feeling about any of these technologies,” he said. “So I personally don’t think it’s such a big deal. I think it’s just going to go away.”

As soon as the company lifts the pause, he added, his center will resume cases with Varipulse.