The nation's largest maker of implanted heart devices, Medtronic, said yesterday that it was urging doctors to stop using a crucial component in its most recent defibrillator models because it was prone to a defect that has caused malfunctions in hundreds of patients and may have contributed to five deaths.
The faulty component is an electrical "lead," or a wire that connects the heart to a defibrillator, a device that shocks faltering hearts back into normal rhythm. The company is urging all of the roughly 235,000 patients with the lead, known as the Sprint Fidelis, to see their doctors to make sure it has not developed a fracture that can make the device misread heart-rhythm data.
Such a malfunction can cause the device to either deliver an unnecessary electrical jolt or fail to provide a life-saving one to a patient in need. In most cases, the defibrillators can be reprogrammed without surgery to minimize the problem.
Medtronic estimated that about 2.3 percent of patients with the Fidelis lead, or 4,000 to 5,000 people, would experience a lead fracture within 30 months of implantation. Those patients will require a delicate surgical procedure to replace the lead, experts said.
Medtronic said it would stop selling the lead and recall all leads not yet implanted.
Replacing leads on a heart device like a defibrillator is considered by experts to be far more dangerous than replacing the device itself. As a result, doctors said that patients were better off leaving the lead in place except in those instances where it has stopped functioning properly.
The Fidelis lead has been used with Medtronic defibrillators since 2004, and most patients who received Medtronic defibrillators since then have them. Patients who have recently had defibrillators replaced because their batteries were running down may not have the leads because doctors commonly attach replacement defibrillators to the existing leads when possible.
Vice President Dick Cheney uses a Medtronic defibrillator, but it was implanted in 2001, before the Fidelis lead was introduced. The White House declined to comment last night.
Questions about the performance of the Fidelis lead have surfaced before. For example, earlier this year, Dr. Robert G. Hauser of the Minneapolis Heart Institute published an analysis that found, among other things, that a significant number of patients were experiencing "inappropriate" shocks because their defibrillator was firing when not needed. Such jolts can be extremely painful.
Dr. Hauser, who played a central role several years ago in bringing to light malfunctions in defibrillators made by Guidant, said that he discussed his findings earlier this year with Medtronic officials, who said there was not enough data to come to any conclusions. In March, however, the company issued a letter to doctors sharing those concerns with doctors.
Last month, when 30 months of data showed a continuing fracture problem, Medtronic began talking with its independent medical advisers about what to do next. "The numbers that we saw were not that bad, but they were worrisome, troubling," said Dr. Douglas P. Zipes, a professor at the Indiana University School of Medicine and a member of the advisory board.
Statistically speaking, there is not enough data to be sure that Fidelis is unusually prone to fracture. But with mounting evidence that there was cause for concern, Medtronic decided to act now. Five deaths have been linked to the fractures as a possible, though not confirmed, contributor.
The numbers suggesting that the problem was significant enough to halt sales of the lead come from two other sources: a clinical trial currently following the progress of 650 patients at 17 hospitals and the mountain of data collected from 25,000 patients in CareLink, Medtronic's system for remotely monitoring implants. Medtronic said that data from fractured leads that have been returned had helped it understand where the malfunctions occur.
Federal safety regulators, who participated in the announcement yesterday, endorsed Medtronic's decision to stop selling the lead.
"Pulling this device from the market is the right thing to do," said Daniel G. Schultz, director of the Center for Devices and Radiological Health at the Food and Drug Administration.
The recall is the latest in a series of setbacks for Medtronic and its two main rivals in the $6 billion global defibrillator market, St. Jude Medical and Boston Scientific, which now owns Guidant. Sales have slumped in the United States in the last two years because of a string of safety recalls and concern among doctors that it is too difficult to identify which patients would benefit from the devices. They can cost $30,000 or more.
Medtronic declined to discuss the potential financial impact of its actions regarding Fidelis prior to a conference call scheduled for this morning with Wall Street analysts. The company, which had $12.3 billion in sales last year, has more than 55 percent of the defibrillator market, and the devices are its biggest product.
Medtronic will cover the cost of a replacement lead for those that have fractured, plus up to $800 in medical expenses that are not covered by insurance. But the company will not pay for procedures to replace functioning leads that patients want taken out to head off possible problems in the future, a company spokesman, Robert Clark, said.
Mr. Clark declined to comment on how many unused leads the company expected to take back and destroy. He said Medtronic would attempt to design a similarly narrow lead to replace the current products.
Medtronic is recommending that doctors switch back to its older Quattro lead, but doctors will have other options from other companies. The biggest long-term financial impact on Medtronic could come not from doctors using other leads but from the possibility that they could switch to complete defibrillator packages from other companies.
Medtronic said that none of its pacemakers used the leads. Pacemakers are device that, instead of shocking a heart back into a stable rhythm, are meany to ensure a continuous steady beat.
Medtronic developed Fidelis as part of the race among cardiac device companies to develop ever more compact and flexible products that can be implanted more easily and safely.
Whatever happens, Medtronic is hoping to contrast its response with that of Guidant three years ago, when deadly defects were discovered in some of its defibrillators. Guidant, which Boston Scientific acquired in 2006, angered doctors and regulators by failing to quickly disclose the problems.
Since then, the Heart Rhythm Society, the professional group for doctors who implant defibrillators, has developed guidelines for handling product safety problems.
Dr. Schultz at the F.D.A. said the company's actions were an indicator of how much the industry had learned from the mistakes made in handling the Guidant malfunction. Dr. Hauser, the Guidant whistle-blower, agreed. "I think that in the old days, this lead could have continued on the market for a long time, maybe forever," he said.