Study Questions Reliability of Cardiac Defibrillators

Cardiac devices called ICDs can detect a heart attack and deliver a strong shock in response. But a new study shows that the machines aren't as reliable as many believed. Nearly one in every 300 has to be replaced.

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Cardiac defibrillators are as small as pagers and can rescue people from sudden death. Vice President Dick Cheney has one and they're one of the fastest growing items in the medical device market. Now, a new report in the Journal of the American Medical Association finds the devices malfunction at unexpectedly high rates, as NPR's Snigdha Prakash reports.


More than a hundred thousand Americans had these devices inserted beneath their skin last year. Their very lives may depend on them, and yet, says cardiologist William Maisel of Boston's Beth Israel Deaconess Medical Center, information on these devices can be hard to come by.

Dr. WILLIAM MAISEL (Cardiologist, Beth Israel Deaconess Medical Center, Boston) Remarkably, if you were interested in purchasing a car you can get much more information regarding crash safety testing, reliability, performance of the engine, gas mileage, all the things that go into a important decision such as purchasing a car you're not able to do when you're trying to purchase a lifesaving device.

PRAKASH: Using information given by the manufacturers to the Food and Drug Administration but not to the public, Maisel has, for the first time, analyzed how reliable these lifesaving devices really are. He says the results are surprising. From 1990 to 2002, an average of one in 50 defibrillators malfunctioned. Two years ago, Maisel surveyed physicians and asked them how reliable they thought these devices were. Most physicians thought that one in a thousand or one in ten thousand malfunctioned.

Dr. MAISEL: I think there is a great misperception about device reliability among physicians. And I don't think that that is their fault. I think it's actually industry's fault for not providing a more realistic estimate of device performance.

PRAKASH: Under current law, manufacturers are free to decide which device problems are serious enough to tell the public and when. The risks of such a voluntary reporting system were highlighted last year when a 21-year-old college student suffered a cardiac arrest and died after his defibrillator malfunctioned.

It emerged that Guidant Corporation, which had made the device, had known about the problem but hadn't told physicians. The company subsequently recalled thousands of the devices. Maisel says the law has to be changed so that companies are required to give the public timely and specific information.

Dr. MAISEL: That information should include malfunction rates; it should include the number and type of malfunctions that have been observed, very detailed reporting of device performance.

PRAKASH: The Food and Drug Administration, which regulates the industry, says it would support fuller disclosure. Bram Zuckerman is director of the FDA Division of Cardiovascular Devices.

Dr. BRAM ZUCKERMAN (Director, FDA Division of Cardiovascular Devices): The opportunity to make this information publicly available through the manufacturers product performance report would have a good public health affect, and the agency would work with manufacturers and physicians to make that a reality.

PRAKASH: The industry group that represents device manufacturers, AdvaMed, says many manufacturers are already doing that. Steve Ubl heads the group.

Mr. STEVE UBL (President, AdvaMed): But I think it's important not to lose the forest for the trees. I mean, defibrillators are a proven technology that have saved hundreds of thousands of lives.

PRAKASH: And on that issue, all sides agree. While growth in defibrillator sales has slowed over the past year because of concerns about safety, William Maisel says nothing in his paper should dissuade a patient who needs a defibrillator from getting one.

Snigdha Prakash, NPR News, Washington.

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