Study Indicates More Heart Units Failing

WASHINGTON – The number of implanted heart defibrillators that fail is increasing as they become more sophisticated, a trend that government officials said Friday is worrisome but difficult to stop.

At a meeting with physicians and heart-device makers, the Food and Drug Administration released a study that found 4,225 defibrillators had failed between 2000 and 2003, about as many as failed in the previous 10 years. Overall, the failure rate of devices was significantly higher in the second half of the period studied than in the first half.

In the FDA study released Friday, researchers found that malfunctioning defibrillators and pacemakers were directly responsible for 61 deaths between 1990 and 2002.

The FDA said on its website that the higher percentage of failures may be a result of design changes that made the devices smaller – they’re now the size of a stopwatch – while their computer memory was increased and their power maintained.

William Maisel, the Harvard Medical School doctor who conducted the FDA study, said the increase was significant and contrasts with a consistent decline in the rate at which pacemakers have to be removed.

Both devices use electric jolts to keep hearts beating properly, but the defibrillators are more sophisticated and have more uses.

Scott Gottlieb, FDA’s deputy commissioner for medical and scientific affairs, said the study’s results and other agency data were disturbing, although the devices remain lifesavers for several million people.

“When we looked across the annual reports we receive about these products, we have found some increasing trends for certain kinds of problems with some devices,” he said at the meeting. “This happened even as these devices got smaller, more sophisticated, and more robust in their lifesaving benefits.”

According to the Heart Rhythm Society, the professional organization that organized Friday’s meeting, as many as 175,000 Americans are likely get defibrillators implanted this year. Their usage has expanded even while serious questions have been raised about the dependability of some models.

One of the biggest defibrillator makers, Guidant, recalled 109,000 implantable devices in June after finding they could develop an internal short circuit without warning, resulting in a failure to deliver a shock when needed.

In the recall notice, the FDA advised patients to discuss with their doctors the advisability of replacing their defibrillators. But Friday, a number of physicians complained that they don’t have all the information they need to make those decisions.