Clinical performance of subcutaneous versus transvenous implantable defibrillator in patients with ischemic cardiomyopathy: data from Monaldi Rhythm Registry

Vincenzo Russo ^1* Alfredo Caturano ¹ Valter Bianchi ² Anna Rago ² Ernesto Ammendola ² Andrea Antonio Papa ² Nadia Della Cioppa ² Annamaria Guarino ² Alessandro Masi ¹ Paolo Golino ¹ Antonio D'Onofrio ² Emilio Di Lorenzo ² Gerardo Nigro ¹

• ¹ University of Campania Luigi Vanvitelli, Caserta, Italy
• ² Monaldi Hospital, Naples, Campania, Italy

Subcutaneous ICD (S-ICD) is an alternative to a transvenous implantable cardioverter-defibrillator (TV-ICD) system in selected patients not in need of pacing or resynchronization. Currently, little is known about the effectiveness and safety of S-ICD in patients with ischemic cardiomyopathy (ICM).The aim of our study was to describe the clinical features and the drivers of S-ICD implantation among patients with ICM, as well as the clinical performance of S-ICD vs. TV-ICD among this subset of patients during a long-term follow-up.All ICM patients with both S-ICD and TV-ICD implanted and followed at Monaldi Hospital from January 1, 2015, to January 1, 2024, were evaluated; among them, only ICD recipients with no pacing indication were included. We collected clinical and anamnestic characteristics, as well as ICD inappropriate therapies, ICD-related complications and infections.A total of 243 ICM patients (mean age 63.0±11.0, male 86.0%) implanted with TV-ICD (n: 129, 53.1%) and S-ICD (n: 114, 46.9%) followed at our center for a median follow-up of 66.9 [39.4-96.4] months were included in the study. Kaplan-Meier analysis revealed no significant difference in the risk of inappropriate ICD therapies (log-rank p=0.137) or ICD-related complications (log-rank p=0.055) between S-ICD and TV-ICD groups. TV-ICD patients showed a significantly higher risk of ICD-related infections compared to those in the S-ICD group (log-rank p=0.048). At multivariate logistic regression analysis, the only independent predictors of S-ICD implantation were female sex [OR: 52.62; p<0.001] and primary prevention [OR: 17.60; p<0.001].Among patients with ICM not in need of pacing or resynchronization (CRT), the decision to implant an S-ICD was primarily influenced by female gender and primary prevention indications. No significant differences in inappropriate ICD therapies and complications were found; in contrast, the S-ICD group showed a numerically reduced risk of ICD-related infections.