Soon, Wireless Implants that can Kickstart Heart
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14 May 2010
By Barry Meier
The likelihood that patients may some day receive heart defibrillators that can operate without electrical wires connected to their hearts has moved a step closer, according to a study.
The development of the new type of defibrillator has been long pursued by a researcher, Gust Bardy, at the Seattle Institute for Cardiac Research in Seattle. And in the study published on Wednesday in the New England Journal of Medicine, Bardy and other researchers reported that initial trials of such a device in patients were successful.
Defibrillators fire an electrical jolt to interrupt a potentially fatal heart rhythm and restore normal beating. For a unit to function, a surgeon must thread an electrical sensing wire through a blood vessel into a patient’s heart. The wires pose risks because they can, on rare occasion, puncture the heart during implantation or fracture while in place.
The new version works much like an external defibrillator, but delivers the electrical jolt by means of a sensor implanted under the skin near the chest bone. A power unit is placed under the skin on the side of the chest.
The new device is already for sale in some European countries, but Bardy and others cautioned that full–scale, long–term trials were still needed to prove the implant’s worth to the Food and Drug Administration. Even if successful, the unit could not be used by all patients who needed a defibrillator, but several experts said they were excited by the new study nonetheless.
Douglas Zipes, a professor at the Indiana University School of Medicine in Indianapolis, said the new device could someday displace existing models used in many patients Every month, about 10,000 patients in the US get a defibrillator, either for the first time or as replacements for devices whose batteries have worn out.
In recent years, the safety of defibrillator wires has come in particular focus because a model made by Medtronic has been prone to fracturing. Hundreds of patients who received the model have had to undergo new operations to replace it. Also, scar tissue often builds up around intravenous wires, a process that can make removing and replacing them difficult or dangerous.