So many things my doctor and Medtronic didn’t tell me: A defibrillator wire defect

Stephanie Martinson, 35, a speech pathologist in Palo Alto, California, said that in March she had a defective wire – a Fidelis lead - removed from the defibrillator device in her heart. The removal was necessary because instead of correctly monitoring her heart rhythm, and only shocking it back into a normal pattern when needed, the Medtronic device had delivered a jolting shock 26 times in an hour. Medtronic notified doctors of the defect, and in May, she received a replacement wire. Unfortunately, the replacement was another Fidelis lead, which may be defective.

"There are so many things my doctors and Medtronic didn't tell me," she said.

Five patients are known to have died because of malfunctions of the device's leads, or wires, which connect the device to the heart.

Medtronic disclosed that the new thin leads have a tendency to form small cracks in the wire, which either blocks or distorts its electrical flow. The flaws may result in faulty signals to the defibrillator, making it unnecessarily shock the heart or fail to deliver a life-saving jolt of electricity when needed.

No one knows how common this problem is. Medtronic says it might affect 2.3% of the 235,000 patients who have the suspect wires, i.e., more than 5,000 patients.

Advice: Tell your friends with implanted defibrillators to ask their doctors whether they have the Medtronic-made Fidelis leads (which have identifying numbers 6930, 6931, 6948 and 6949, on their wallet card), and if so, to schedule computerized testing of the device.

Read another defibrillator story, or read the source stories by Barry Meier and Lawrence Altman in today's New York Times.