Audible implantable cardioverter defibrillator alarms detect intermittent conductor discontinuity

The lead conductor integrity of implantable cardioverter defibrillator devices is inferred from impedance measurements; however, intermittent discontinuity can be difficult to detect or confirm. Newer devices can perform daily lead impedance self-testing, and some even have audible alarms that promptly warn patients of anomalies. In the present case, the audible alarms were solely responsible for the timely identification of an intermittent, otherwise clinically nonreproducible, form of potentially fatal implantable cardioverter defibrillator system failure.