St. Jude Pulls Defibrillator Cables From Market

A group of defibrillator cables from St. Jude Medical Inc. is being taken off the market amid concerns that the electrical insulation could cause the devices to malfunction.

The St. Paul, Minn.-based medical device behemoth discussed its decision in a Dec. 15 letter to doctors, saying a new version of the cables (with a newer insulated coating as well) are not subject to malfunctions. The newer cables already have replaced older ones on the market and they represent about 97 percent of the company’s defibrillator cable lead sales, The Wall Street Journal reported.

In its physician letter, St. Jude cited a 0.47% rate of “insulation abrasion” over nine years of use with the defective leads, noting a phase-out of the cables should be completed by the end of the year, Fox Business claimed. According to published reports, the defective insulation can intrude on the way cables sense cardiac rhythm problems.

Implantable defibrillators are designed to keep the heart beating regularly and shock it back to its proper rhythm in the event the organ fails. A defibrillator lead is a thin wire attached to the heart wall that delivers an electrical impulse through the defibrillator. When a defibrillator wire detaches or breaks, the device will fail leaving a patient at risk for death because the device does not sense the need for a shock, is unable to deliver the shock, or delivers an unnecessary shock. If the wire perforates the heart wall, the heart can bleed into its pericardial sac causing cardiac tamponade, a lethal condition where pressure builds around the heart preventing it from beating effectively. Heart perforation generally is discovered after the wire has made its way through the heart wall.

In its letter, St. Jude said the newer leads insulation is called “Optim” and has exhibited better than an 80 percent reduction in so-called “abrasion-related observations” after 44 months versus leads made with silicone, said Fox Business, which noted that the Optim insulation is comprised of both silicone and polyurethane.

“The insulation is the weakest link” for defibrillator leads, Haris Haqqani, an electrophysiologist at the Hospital of the University of Pennsylvania, told Fox Business. He said the industry has been working to phase out coatings that were developed for other applications and use materials that are more specifically designed to handle the bending, strain and other challenges that leads face inside the body.

A U.S. Food and Drug Administration spokeswoman told Fox Business that the issue does not yet warrant a recall. St. Jude is not recommending that the cables be removed because the procedure is too complex, according to published reports. St. Jude’s medical advisory board agreed.