Guidant CONTAK RENEWAL 3 RF (models H210, H215), CONTAK RENEWAL 3 RF HE (models H217, H219) ,CONTAK RENEWAL 4 RF (model H230), and CONTAK RENEWAL 4 RF HE (model H239) cardiac resynchronization therapy defibrillator (CRT-D). Guidant Corporation, 4100 Hamline Avenue North, St. Paul, MN 55112-5798 USA.

Shock Effectiveness: there is a potential for malfunction of a high voltage wire, which could compromise effectiveness of shock therapy. While no energy is lost, defibrillation thresholds may be higher (and safety margin may be reduced) because the shocking vector has changed.

An Important Medical Device Information letter, dated 10/09/2006 was sent to physicians following patients with a potentially affected device. The letter describes the issue, provides for a projected rate of occurrence, and provides recommendations. An October 9, 2006 Product Advisory Letter, beginning October 30, 2006, was also sent to provide an update that further laboratory testing and analysis indicates that the nominal probability of malfunction is higher than their earlier prediction. Non-implanted devices have been retrieved.