Comparison of complications and shocks in paediatric and young transvenous and subcutaneous implantable cardioverter-defibrillator patients

Background: Young implantable cardioverter-defibrillator (ICD) patients are prone to complications and inappropriate shocks (IAS). The subcutaneous ICD (S-ICD) may avoid lead-related complications. This study aims to describe the incidence and nature of device-related complications in young transvenous ICD (TV-ICD) and S‑ICD patients. Methods: Single-chamber TV-ICD and S‑ICD patients up to and including the age of 25 years implanted between 2002 and 2015 were retrospectively analysed. Complications were defined as device-related complications requiring surgical intervention. IAS were defined as shocks for anything other than ventricular tachycardia or ventricular fibrillation. Follow-up data were collected 5 years post-implantation. Kaplan-Meier estimates for complications at 5‑year follow-up were calculated with a corresponding 95% confidence interval. Results: Eighty-one patients (46 TV-ICD, 35 S-ICD) were included (median age 19.0 (IQR 16.0–23.0) and 16.5 (IQR 13.0–20.2) years respectively). Median follow-up was 60 and 40 months respectively. All-cause complication rate was 34% in the TV-ICD group and 25% in the S‑ICD group (p = 0.64). TV-ICD patients had more lead complications: 23% (10–36%) versus 0% (p = 0.02). The rate of infections did not differ between TV-ICD and S‑ICD: 2% (0–6%) versus 10% (0–21%) (p = 0.15). No systemic infections occurred in the S‑ICD patients. The rates of IAS were similar, TV-ICD 22% (9–35%) versus S‑ICD 14% (0–30%) (p = 0.40), as were those for appropriate shocks: 25% (11–39%) versus 27% (6–48%) (p = 0.92). Conclusion: The rates of all-cause complications in this cohort were equal, though the nature of the complications differed. S‑ICD patients did not suffer lead failures or systemic infections. An era effect is present between the two groups.