Possibility of the Subcutaneous Implantable Cardioverter-Defibrillator for Prevention of Sudden Cardiac Death in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy

Abstract

The EMBLEM™ entirely subcutaneous implantable cardioverter-defibrillator (S-ICD) system (Boston Scientific, Marlborough, Massachusetts, USA) was introduced as a new alternative to the conventional transvenous implantable cardioverter-defibrillator and has been expected to reduce device-related complications, especially in young patients who require long-term lead placement. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a well-known hereditary disease recognized as a cause of sudden cardiac death (SCD) in young adults. However, the precise clinical role of S-ICD in patients with ARVC remains to be defined because of the low QRS amplitude of subcutaneous electrocardiogram (S-ECG) followed by the high incidence of inappropriate shock (IAS) delivery due to oversensing. It is well known that the sensing of S-ICD is largely dependent on the QRS/T ratio of S-ECG. The decrease in the QRS amplitude is more likely to lead to oversensing such as T wave or myopotential oversensing. In patients with ARVC, the decrease in the QRS amplitude due to degeneration of the right ventricular myocardium progresses overtime. In this chapter, we would like to discuss the usefulness of S-ICD lead repositioning for young adult patients with ARVC based on our experience of patients with IAS.