An increasing number of patients have a coexisting implantable cardioverter defibrillator (ICD) and left ventricular assist device (LVAD) to treat ventricular arrhythmias and refractory heart failure, respectively. To date, there have been no published reports of negative interactions between these devices that have impacted appropriate ICD or LVAD function. In this case report, we describe a patient with an LVAD-ICD interaction that necessitated replacement of the implantable defibrillator.