Medical device maker Medtronic Inc. said on Friday it has begun warning doctors about some faulty batteries installed in a line of its implantable heart defibrillators.
The problem involves batteries in its Marquis line of implantable cardioverter defibrillators (ICDs) made before December 2003, Marshall Stanton, medical director of Medtronic's cardiac rhythm management unit, told Reuters.
Stanton said the battery problems occurred in nine patients out of 87,000 worldwide.
He said Medtronic would send letters detailing the problem to physicians who have implanted the devices.
ICD batteries typically last for several years.
Stanton said the problem does not involve Medtronic's Intrinsic and Sentry ICD lines, or any Marquis ICD made after December 2003.
For patients using an ICD primarily for its pacemaker functions, the device will need to be replaced in a procedure requiring no more than 45 minutes, according to Alan Kadish, a cardiologist at Northwestern Memorial University in Chicago.
These are patients who need the device to keep every single heartbeat on track, as opposed to those who need it for an occasional irregular heartbeat, he said.
Medtronic, which makes its own ICD batteries, discovered the potential for rapid battery depletion during lab testing.
The company changed to a new battery design in December 2003.
"The only substantial risk here is the risk of infection" when opening the patient up, Kadish said.
I don't think it will harm anybody physically, but it is making for a lot of work," said Silver, who has 39 patients with the Marquis devices.
Earlier on Friday, JP Morgan analyst Michael Weinstein said in an analyst note the company had begun calling doctors to warn of the problem, but characterized the letter as a "nonevent."