BACKGROUND: Implantable cardioverter-defibrillator (ICD) systems are established for the prevention of sudden cardiac death. Data on patients with inherited arrhythmogenic syndromes is sparse as these diseases are rare but of eminent importance as this group of patients is young and normally not affected by heart failure. Furthermore, ventricular arrhythmias often consist of ventricular fibrillation so that these patients may not to benefit from antitachycardia pacing options of transvenous ICDs.

METHODS AND RESULTS: The present study represents a single-center experience of patients with inherited arrhythmia syndromes (n = 42) with Brugada syndrome, Long QT syndromes and catecholaminergic polymorphic ventricular tachycardias (CPVT9 being most common. Follow-up data included regular in-house follow-up visits as well as unscheduled hospitalizations and telemedicine interrogations in our center. Mean age at implantation was 36.4 ± 14.9 years and 17 patients (40%) were male. Mean follow-up duration was 5 years. One patient died during the observation period due to septic shock, no cardiovascular death occurred. 22 patients were implanted for primary prevention, while 20 patients suffered from sustained ventricular arrhythmias before (n=12 VF, n=8 monomorphic VT, n=2  polymorphic VT). Appropriate shocks occurred in 6 patients (14.3%), inappropriate shocks in 4 patients (9.5%). T-wave oversensing was the main cause for inappropriate shock delivery (3 out of 4 patients), in the other patient myopotentials during sport were the reason for inappropriate therapy. In one patient with short-coupled variant of torsade de pointes, there was one ineffective shock during electrical storm so that the system was changed to a transvenous ICD thereafter. There were no other system changes. In one patient with appropriate shocks, successful VT ablation prevented further S-ICD shocks.

CONCLUSION: The S-ICD shows a reliable performance during a relatively long-term follow-up. All but one episodes of ventricular arrhythmia could be terminated with the first shock. T-wave oversensing was the most common reason for inappropriate shock delivery and could be prevented by changing the sensing vector.