When Implanted Heart Devices Fail
The Odds -- and Consequences -- of Pacemaker, ICD Breakdowns
The Risk of Pacemaker, ICD Failure continued...
The usual problem with FDA data is that the FDA adverse-event reporting system is voluntary. Might missing reports have skewed the data?
"Combined, the studies included patients implanted with several hundred thousand pacemakers and thousands of ICDs," Maisel says. "The results were amazingly consistent with the FDA reports. They also showed that the pacemaker malfunction rate has declined significantly. The ICD malfunction rate also declined notably from the 1980s to the mid-1990s, but again we saw an increase in the ICD malfunction rate from 1990 to 1992. The rate of malfunction for ICDs increased more than fourfold from 1998-2001."
There is good news, however. New data from 2003 and 2004 show what Maisel calls "a reassuring decline in the ICD malfunction rate, almost back down to the lowest levels seen in the 1990s."
Does the risk of a breakdown mean you should think twice about getting a pacemaker or ICD device? Maisel doesn't think so -- if your doctor says you really need one.
"The chance someone will be saved by one of these device about a thousand times greater than the chance the device will fail when they need it," Maisel says.
He notes that there were 30 deaths due to pacemaker malfunction and 31 deaths due to ICD malfunction among the 2.7 million patients who had one of these devices.
ICD Replacement Risks
ICD breakdown isn't the only risk of getting one of these implants, find cardiologist Andrew D. Krahn, MD, of University of Western Ontario in London, Canada, and colleagues.
When a device breaks down, manufacturers sometimes discover a design flaw or manufacturing error. That leads to product "advisories" that warn patients of potential problems. This puts the patient in a major dilemma. Should patients risk device failure, or should they risk the operation to have the device removed and replaced?
"We saw the other side of the coin: not devices failing, but patients suffering due to recall of devices," Krahn tells WebMD.
Getting an ICD implant isn't a major operation. But replacement can be tricky. The patient is older, there may be scar tissue, and there is more risk of a deadly infection after surgery. How dangerous is it? Krahn's team surveyed nearly all the doctors in Canada who do these procedures.