INDIANAPOLIS -- New defibrillators implanted in the chests of about 2,000 Americans need to be adjusted because a few of them have a programming error that can make the heart race, the manufacturer says.
No deaths have been linked to the Ventak AV, sold by Indianapolis-based Guidant Corp. The problem might be life-threatening under certain circumstances, one doctor said, but another said that is unlikely.
Patients won't have to get the defibrillators surgically removed. Doctors can adjust the devices' programming without opening the chest by using a small radio transmitter.
Implantable defibrillators treat patients prone to rapid heartbeats by delivering small electrical shocks to the heart via a wire inserted into the organ. The Ventak AV sells for $24,400 in the United States.
In three of the 2,000 U.S. patients who have received the devices since July, heart rates went to 190 beats per minute for three to five seconds, the company said. About 3,000 of the devices have been implanted worldwide.
"It would feel like your heartbeat is running away," said Dr. Douglas Zipes, a heart expert at the Indiana University Medical School.
The company said it is contacting doctors to identify patients whose defibrillators contain the faulty program to see that they get an immediate modification.
Patients whose devices have programs that indicate no risk can wait until their next regularly scheduled visit to their doctor, it said.
Zipes said healthy people can tolerate heart rates of 190 beats per minute, or close to three times their resting pulse, for as long as a few hours. Patients with heart disease that requires an implantable defibrillator face more serious risks, such as blackouts, he said.
In some circumstances, the accelerated heart rate could trigger a condition known as ventricular defibrillation, which can lead to death, Zipes said. However, a properly working defibrillator would recognize that condition and deliver a shock that returns the heart it to a normal pulse, Zipes said.
Dr. Hugh Calkins, director of electrophysiology at Johns Hopkins Hospital in Baltimore, said that because the rapid heart rate doesn't last long, patients might feel dizzy, but "it's very unlikely to cause a life-threatening problem."
The Food and Drug Administration learned of the Ventak problem Monday and approved Guidant's method of fixing the software.
"We are in the process of collecting information ... to make an assessment of the seriousness of the problem," said FDA spokeswoman Sharon Snider.
The company has had other problems with the Ventak AV. In February, it halted shipments to Europe and suspended new implants because of problems in nine units out of 200. Spokeswoman Carol Lindahl said the earlier problem was corrected and is not related to the latest one.
Guidant, spun off from Eli Lilly & Co. two years ago, saw its stock fall $3.50 per share Monday. But it rebounded $2.56 per share to close Tuesday at $64.00 on the New York Stock Exchange.