Unexpected Battery Depletion of St Jude Implanted Cardio-Defibrillators

Background: The batteries of implanted cardio-defibrillators (ICD) of several models of St. Jude Medical have been reported to undergo early battery depletion. Patients with these models at Wolfson Medical Center, Holon, Israel were followed for their outcomes. Methods: All patients implanted with the Unify^TM, Fortify^TM and Assura^TM series of ICDs were examined and followed in a heightened surveillance pacemaker clinic schedule as well as via the Merlin^TM home monitoring system for death or premature battery depletion.

Results: A total of 46 patients followed at Wolfson Medical Center, Holon had been implanted with these models. In the initial screening, two patients with premature depletion were identified, and during the following 15 month follow up, two more presented, for a total four patients (8.6%). The manifestation of battery depletion was diverse: one with abrupt battery failure, one with premature depletion, and two were identified via home monitoring alerts.

Conclusions: The battery failure rate of these models is far higher than that has been reported previously, and the failure may be without warning. Clinicians should be aware of this and carefully consider risk-benefit ratio to identify those who may benefit from prophylactic generator change.