Early Failure of Subcutaneous ICD in a Patient With a Variant of Rapidly Progressive ARVC.

backgroundA subcutaneous implantable cardioverter defibrillator (S-ICD) is a validated alternative to a transvenous ICD for patients without pacing indications. However, limited data exist regarding its safety and efficacy in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). CASE SUMMARY: A 21-year-old man was referred after a syncope during a sport event. A 12-lead electrocardiogram showed repolarization abnormalities, and cardiac magnetic resonance demonstrated right ventricular dilatation, biventricular dysfunction, and fibrosis compatible with a diagnosis of ARVC. An S-ICD was implanted after successful preimplant screening. Genetic testing identified a known pathogenic plakophilin-2 variant. The patient received an S-ICD. At 18 months, lead noise, undersensing, and oversensing occurred because of reduced QRS amplitude. Imaging confirmed disease progression. The S-ICD was explanted and replaced by a transvenous ICD. The patient was referred for heart transplant evaluation. DISCUSSION: Our case represents a phenotype variant of ARVC with failure of the S-ICD system due to a temporal change in QRS amplitude over a short period of time. Advanced discrimination algorithms on the S-ICD may not be sufficient to prevent device failure. Cardiac magnetic resonance and genetic testing could eventually play a major role in the selection of a device in patients with ARVC. TAKE-HOME MESSAGE: This case illustrates S-ICD failure associated with rapidly progressive ARVC, underscoring the need for close follow-up and tailored device selection in this population.