The entirely subcutaneous ICD^TM system in patients with congenital heart disease: experience from a large single-centre analysis

The subcutaneous implantable cardioverter-defibrillator (S-ICD^TM) is an important advance in device therapy for the prevention of sudden cardiac death (SCD). Although current guidelines recommend S-ICD^TM use, long-term data are still limited, especially in subgroups such as adult patients with congenital heart diseases. This cohort is of high interest because of the difficult anatomic conditions in these patients.

All S-ICD^TM patients with an underlying congenital heart disease (CHD) resulting in an indication for ICD implantation (n = 20 patients) in our large-scaled single-centre S-ICD^TM registry (n = 249 patients) were included in this study. Baseline characteristics, appropriate and inappropriate shocks, and complications were documented in a mean follow-up of 36 months. Primary prevention of SCD was the indication for implantation of an S-ICD^TM in six patients (30%). Of all 20 patients with an overall mean age of 40.5 ± 11.5 years, 12 were male (60%). The mean left ventricular ejection fraction was 46.5 ± 11.3%. Nine episodes of ventricular tachycardia (two monomorphic and seven polymorphic) were adequately terminated in three patients (15%). In two patients, T-Wave-Oversensing resulting in an inappropriate shock was observed, which could be managed by changing the sensing vector or activation of the SMART PASS^TM filter. There were no S-ICD^TM system-related infections. In one patient, surgical revision was necessary due to a persistent haematoma.

The S-ICD^TM seems to be a valuable option for the prevention of SCD in patients with various CHDs and complex anatomical anomalies. The S-ICD^TM is safe and works effectively, also in these complex patients. Inadequate shock delivery was rare and could be managed by reprogramming.