Sale of heart device wire suspended

Decision underscores dearth of safety data on key part, experts say

October 16, 2007|By New York Times News Service

The decision by Medtronic, the market leader in defibrillators, to stop selling a widely used part for implanted heart devices underscores the dearth of safety monitoring of such products, as well as a design trend that might make them increasingly prone to failure, several experts said yesterday.

Over the past two years, since the disclosure of safety problems with heart defibrillators made by another producer, Guidant, device makers and regulators have paid closer attention to tracking defibrillators after they reach the market.

But several experts said yesterday that there was no similar focus on a crucial component of those products - the wires, or leads, that connect them to the heart and convey the potentially life-saving shocks. Defibrillators are designed to deliver an electric shock, when necessary, to stabilize a dangerously erratic heartbeat.

Medtronic has earned plaudits from the Food and Drug Administration and cardiologists for its announcement Sunday, voluntarily urging doctors to stop using a family of leads known as the Sprint Fidelis, because they are prone to cracking, with potentially life-threatening consequences. An estimated 235,000 patients are thought to have Fidelis leads, and the company estimates that 4,000 to 5,000 patients - or about 2.3 percent - will experience fractures in the leads.

But there are also suggestions that Medtronic, at least until relatively recently, was operating somewhat in the dark because of limited data about the problem's scope. Meanwhile, FDA records suggest that a patient death apparently linked to the problem occurred in 2006, well before Medtronic sent an alert to doctors.

Dr. William Maisel, a heart device expert at Beth Israel Deaconess Medical Center in Boston, said that Medtronic's warning appeared to be another instance of industry executives and regulators scrambling to catch up to a problem, rather than creating ways to anticipate it.

"What is frustrating here is that this was another situation that was predicable," said Maisel, who is also a consultant to the FDA.

Yesterday, Medtronic and several of its outside consultants said that the company's decision to halt the device's use was a close call, because the available data about its failure rate was not overwhelming.

"We decided that the right thing to do for patients was a conservative one," said Rob Clark, a company spokesman.

Medtronic paid a price in the stock market yesterday, as its shares fell more than 11 percent on news of the safety warning and after the company said it expected the problem to cut sales in the current quarter by up to a quarter of a billion dollars.

Meanwhile, an inevitable wave of personal injury lawsuits began yesterday, including one filed in federal court in Minneapolis, where Medtronic is based.

The problem that Medtronic disclosed is a tendency for cracks to form in the wire, which either blocks or distorts its electrical flow. The flaws may result in faulty signals being sent to a defibrillator, causing it to unnecessarily shock the heart or, in rare instances, to fail to deliver a life-saving jolt when needed.

Several medical experts said they suspected that the device's problems might reflect the fact that the Fidelis is the thinnest lead made by Medtronic.

Some cardiologists said yesterday that they believed the new thinner leads might not be durable enough to survive either the pressure of implantation or the stresses exerted on them once they are in the body.

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