Characteristics and safety of elective second generator replacement in subcutaneous implantable cardioverter-defibrillators
Y Matsuda, K Kooiman, A De Weger, L Smeding, L R A Olde Nordkamp, R E KnopsAbstract
Background
It has been many years since in 2009 the subcutaneous implantable cardioverter-defibrillator (S-ICD) became available, and an increasing number of patients are now receiving a second S-ICD generator replacement. However, there are no reports on the characteristics and outcomes of the second S-ICD generator replacements.
Purpose
The purpose of this study was to investigate the characteristics and outcomes of second S-ICD generator replacement, comparing them with those at index implantation and at the first generator replacement.
Methods
This study was a retrospective, observational, single-center study, and patients undergoing second S-ICD generator replacement in our hospital were consecutively included. The main outcomes were the defibrillation test (DFT) success rate, shock-impedance, and major complications which needed invasive interventions within 30 days of the procedure.
Results
Between June 2021 and June 2025, 36 consecutive patients underwent second S-ICD generator replacement. All patients received a first generation S-ICD (Cameron Health 1010) during index S-ICD implantation. The median duration from the index S-ICD implantation to the second generator replacement was 12.0 (11.3-13.5) years, and the median duration from the first generator replacement to the second generator replacement was 6.3 (5.5-7.5) years. A PRAETORIAN score after second generator replacement was obtained for 11 (30.6%) patients. There was no significant difference in the PRAETORIAN score between at the index S-ICD implantation and at the second generator replacement (30 [30-60] vs. 60 [30-60] points, p=0.564). DFT was performed in 28 (77.8%) patients at the second generator replacement. The DFT success rate within a shock of ≤80 J was comparable for each procedure (index S-ICD implantation: 97.2%; first generator replacement: 100%; second generator replacement: 96.4%, p=0.368) (Figure 1). One patient who failed DFT at the second generator replacement succeeded the DFT after generator repositioning. There was no significant difference in shock-impedance among the procedures (index S-ICD implantation: 79.1 ± 22.9 Ω; first generator replacement: 86.2 ± 32.7 Ω; second generator replacement: 86.5 ± 21.2 Ω, p= 0.083) (Figure 2). In terms of safety outcomes, there was no significant difference in the major complication rate for each procedure. One patient (2.8%) had a major complication after the index S-ICD implantation, and there were no major complications after the first or second generator replacement (p=0.368).
Conclusions
The DFT success rate, shock-impedance and major complication rate at the second S-ICD generator replacement were similar to those at the index implantation and at the first generator replacement. These results support the long-term safety and efficacy of S-ICD therapy.The comparison in DFT success rateThe comparison in shock-impedance