Introduction: Experience with the subcutaneous implantable cardioverter-defibrillator (S-ICD) is expanding rapidly. However, data on long-term performance or complications related to elective generator replacement are lacking. Methods: Follow-up (FU) data of all patients implanted between December 2008 and April 2011 were collected. Complications were defined as those requiring surgical intervention. Kaplan-Meier estimates for complication and shock rates, with corresponding 95% confidence intervals (CI), were calculated. Results: One hundred and eighteen patients were included. Median FU was 6.1 years (IQR 5.6–6.5 years). Short-term complication rate (0–30 days) was 3% (CI 0–6%). Long-term complication rate at 6 years was 19% (CI 12–26%), corresponding with an annual complication rate of 3%. One patient in this cohort developed a need for a transvenous ICD (TV-ICD) in order to provide pacing for bradycardia (1%). Six patients were implanted with a TV-ICD after experiencing an S-ICD complication for which extraction was necessary. In total, 10 S-ICDs were extracted; none resulted in a complication. Eight patients had a nonsystemic ICD-related infection and no lead failures were observed. The majority, 68 (58%) patients, received an elective generator replacement. Two patients had a complication related to generator replacement (3%). Battery longevity was 5.6 years (IQR 5.2–6.1). Appropriate and inappropriate shock rates of 6-year estimates were 17% (CI 9–25%) and 21% (CI 15–27%), respectively. Conclusions: This cohort represents the longest follow-up to date and shows a low annual complication rate without lead failures or systemic infections. Battery longevity of the first S-ICD generation results in relative early generator replacement procedures.

Additional Metadata
Keywords battery longevity, complications, long-term performance, replacement, subcutaneous ICD, ventricular tachycardia
Persistent URL dx.doi.org/10.1111/jce.13498, hdl.handle.net/1765/109272
Journal Journal of Cardiovascular Electrophysiology
Citation
Quast, A.-F.B.E. (Anne-Floor B. E.), van Dijk, V.F, Yap, S-C, Maass, A.H, Boersma, L, Theuns, D.A.M.J, & Knops, R.E. (2018). Six-year follow-up of the initial Dutch subcutaneous implantable cardioverter-defibrillator cohort: Long-term complications, replacements, and battery longevity. Journal of Cardiovascular Electrophysiology, 29(7), 1010–1016. doi:10.1111/jce.13498