Boston Scientific has warned that some defibrillators produced by its recently acquired subsidiary Guidant may suddenly stop working due to a battery malfunction, adding that it is working to make its postmarket surveillance of device performance more transparent.

In a letter warning physicians about the problem, Boston Scientific said the issue is a faulty capacitor contained in the Vitality HE implantable cardioverter defibrillator (ICD) and the Contak Renewal 3 and 4 cardiac resynchronization therapy defibrillators (CRT-D). The capacitor problem was confirmed in 30 defibrillators removed from patients as of May 8 and is suspected in 46 devices that are still implanted in patients. There have been no deaths or injuries linked to the device failures, the company noted. The device malfunctioned in two patients who underwent successful replacement procedures.

Boston Scientific became aware of these specific device failures after it acquired Guidant in April, although Guidant has had a long-running stream of failures and recalls. In November 2005, the company established a panel of outside experts to recommend changes to its product development policies for cardiac devices. The review panel identified a progression of organizational lapses in which Guidant failed to adequately communicate to physicians the risk of its defibrillators short-circuiting, or "arcing" -- even after the company had learned of that risk.

Boston Scientific said in a May 10 regulatory filing it is battling at least 300 legal claims related to Guidant defibrillators that had potentially fatal flaws in battery components. ()a href="http://www.fdanews.com/ddl/33_21/" target=_blank>