Po-03-058 s-icd generator exchange and performance: a single tertiary care experience

Limited data exist on outcomes of subcutaneous implantable cardiac defibrillators (S-ICDs) generator exchange. Few studies have found that shock impedance increases after S-ICD Gen exchange which correlates with increase in DFT and possibly reduction in S-ICD effectiveness. We describe the performance of S-ICDs after generator exchange in a cohort of patients implanted and followed in a single tertiary-care referral center. We reviewed the device clinic interrogation reports of 525 patients who received S-ICDs between 2012 and 2022 and compared device parameters before and after generator exchanges specifically high-voltage impedance and shock efficacy during follow-up using the paired sample t-test with a 95% CI and p-value of 0.05. A total of 525 S-ICDs were implanted at our facility with an average age at implant of 51±16 years, predominantly males (n=348, 66.3%). The majority of S-ICDs were implanted for primary prevention (413, 79%), and ischemic cardiomyopathy (CM) was the most common type of CM (127, 24%). The average ejection fraction (EF) was 30±12%, and comorbidities were prevalent: 56% hypertension, 29% diabetes, 38% with history of coronary artery disease (CAD), and 33% end-stage renal disease (ESRD). Of those, 76 (15%) underwent generator battery exchange at a median time of 4.5± 2 years. Before generator exchange, a total of 114 shocks (22%) were delivered with an impedance of 68± 23Ω. Of those, 89 (78%) were appropriate shocks. Efficacy of the appropriate shocks was 95%. [F1] [IR2] After generator exchange (n=76), 10 appropriate shocks (13%) were administered with an impedance of 82± 29 Ω, and a shock efficacy of 100%. High voltage impedance and shock efficacy were not statistically different before and after Gen exchange (p=0.178 and p=0.158 respectively). The S-ICD generator exchange demonstrates high safety profile with relatively no change in device impedance or shock efficacy pre- and post- Gen exchange.