By Peter Loftus

Johnson & Johnson's halt of U.S. sales of a new heart-rhythm device due to safety concerns is hobbling a major strategic push by the company into one of the industry's fastest-growing markets.

The healthcare company paused use of the device, known as Varipulse, last month after receiving reports of neurovascular events in several patients. The company didn't explain what the events were, but several strokes have been reported to a federal device-safety database, and doctors' concerns are centered on strokes.

J&J has been racing to catch up to competitors in the fast-growing market for medical devices treating irregular heart rhythms, and to revive the company's medical-device business generally.

Rivals Boston Scientific and Medtronic have dominated the market for so-called pulsed-field ablation devices, which research firm Clarivate estimates will reach about $12 billion by 2032, from $1.6 billion last year.

More than 10 million Americans have the heart-rhythm disorder that the devices treat.

"This is a huge hit for J&J," said Dr. John Mandrola, an electrophysiologist at Baptist Health in Louisville, Ky., who treats patients with heart-rhythm problems. "The market's so big, and this just sets them back."

The company said it paused U.S. use of the device out of an abundance of caution and is investigating the health problems in collaboration with U.S. regulators. The company said the pause didn't affect use of Varipulse outside the U.S. Globally, more than 3,000 patients have been treated with Varipulse.

"We continue our commercialization of Varipulse outside of the U.S., and we're working very hard to be able to identify the root cause and bring Varipulse back into the U.S.," J&J Chief Executive Joaquin Duato said at an investor conference last month.

The Food and Drug Administration, which regulates device safety, is aware of the side effects and is working with J&J, an agency spokesperson said. The FDA will alert the public and healthcare personnel of any further action.

The pulsed-field ablation devices promise to transform the treatment of hearts that beat too fast, too slow or erratically.

For patients at high risk of cardiac arrest, doctors had prescribed drugs or implanted a device like a pacemaker to help the heart beat in a regular rhythm. Other patients can undergo a minimally invasive procedure called an ablation, which involves snaking a catheter through a blood vessel to the heart.

Older ablation devices destroyed unhealthy heart cells by zapping them with microwaves or other energy. The older devices, however, could also damage the nearby esophagus, potentially fatally.

Device makers say pulsed-field ablation procedures are faster and safer. The new devices zap heart cells with rapid, high-voltage bursts of electricity through a catheter.

J&J's medical-device business is one of the biggest in the industry, with more than $31 billion in annual sales. The division's sales growth, though, has lagged behind the company's pharmaceutical unit, and J&J has tried to boost growth via acquisitions such as last year's purchase of Shockwave Medical for $13 billion.

The medical-device business was a market leader for older ablation products, but in pulsed-field ablation it fell behind Boston Scientific and Medtronic, which were first to launch their newer models about a year ago.

Unusually for a medical device, sales quickly soared. Boston Scientific recently reported more than $1 billion in sales last year for its Farapulse product's use in more than 200,000 patients. Medtronic hasn't broken out sales for its devices, PulseSelect and Affera.

Varipulse was going to help J&J defend its ablation market share. The design of the catheter component was based on an earlier J&J device that was never launched in the U.S. because of safety issues, Wells Fargo analyst Larry Biegelsen said in a research note.

J&J said the Varipulse catheter has unique features that are different from the older catheter, though some features are similar.

There were two strokes in patients in the pivotal U.S. clinical trial of more than 270 patients. J&J said the incidence of adverse events among patients in the trial wasn't outside thresholds in clinical literature.

After concluding the device's benefits outweighed the risks, the FDA approved it in November. J&J then began a limited rollout in the U.S. to collect feedback from doctors.

The company issued its pause last month after four out of 130 patients experienced the undefined neurovascular events. Neither J&J nor regulators have said whether the device caused the side effects, or why.

Since J&J's initial disclosure, four more stroke events have been reported to a federal device safety database, bringing the total to eight strokes. And two stroke-like events known as transient ischemic attacks have been reported in people treated with Varipulse .

Heart specialists say the number of strokes reported so far is high for the small number of patients treated, signaling a potential problem with the device. The pause could tarnish the J&J product in the eyes of doctors and limit future use if procedures resume.

"I think the rate of adoption of that catheter is not going to be as much as it would have been if it had not had this history," said Dr. Komandoor Srivathsan, an electrophysiologist with the Mayo Clinic in Phoenix.

Write to Peter Loftus at Peter.Loftus@wsj.com

(END) Dow Jones Newswires

February 14, 2025 08:00 ET (13:00 GMT)

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