Multiple appropriate and spurious defibrillator shocks in a patient with right ventricular cardiomyopathy

An implantable cardioverter defibrillator (ICD) has been implanted in a 69-year-old patient with arrhythmogenic right ventricular cardiomyopathy (ARVC) for treatment of syncopal ventricular tachycardia (VT). Two types of ICD-related emergencies complicated the clinical course within 15 months. The first arrhythmic event occurred 3 months after ICD implantation as electrical storm with repetitive fast VT, resulting in 87 consecutive shocks at maximal output. Intravenous administration of amiodarone and reprogramming of the device were the measures to control VT. A year later, the patient experienced a cluster of 97 inappropriate shocks. Lead insulation failure produced electrical noise on the ventricular sensing channel and was misidentified as ventricular fibrillation (VF). The depleted ICD and the dual-coil lead were explanted and replaced by a new system. Multiple ICD shocks constitute a medical emergency in ICD patients, which requires immediate device interrogation for differentiation of appropriate and spurious discharges.