Mechanisms and management of inappropriate therapy in subcutaneous implantable cardioverter defibrillators

Subcutaneous implantable cardioverter defibrillators (S-ICDs) provide reliable defibrillation and have enhanced supraventricular tachycardia discrimination and fewer infection rates compared with traditional transvenous systems. However, inappropriate shocks remain a frequent problem. Herein, we review the various mechanisms of these inappropriate therapies, some of which are unique to S-ICDs, and propose an algorithm for preventing recurrences. Proper screening of preimplants is essential to help minimize inappropriate therapies, but patients with hypertrophic cardiomyopathy, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy are at particular risk and may require additional measures.