Guidant Corporation said today that a programming change it suggested to doctors in June for its Ventak Prizm, Vitality and Contak Renewal implantable defibrillators might actually increase the risk of malfunction in these models. Guidant ‘s Ventak Prizm, Vitality and Contak Renewal defibrillators are implanted in about 21,000 heart patients worldwide.

The company discovered that a malfunction occurred in one of the devices after it was reprogrammed. In that instance the patient was not injured but had to have the device replaced. Guidant is now investigating other reports of malfunctions, including a possible personal injury. Last month Guidant issued safety warnings on 11 defibrillator models after several deaths were linked to defective medical devices. The FDA went on to classify Guidant ‘s safety warnings as recalls.

On July 18, Guidant also issued warnings on 9 of its implantable pacemaker models, which the FDA classified as Class I recalls on July 22. Class I is considered the most serious recall class issued by the FDA and is reserved for devices that are likely to cause serious personal injury or even death. The company promised it would have a permanent fix available for its defective defibrillators, pending FDA review, in the fourth quarter of this year.

Sources: “Guidant’s defibrillator fix may raise other risks,” Associated Press, July 23, 2005; “Guidant revises recommendations on ICD fix,” Reuters, July 22, 2005.