Long-term follow-up of subcutaneous ICD systems in patients with hypertrophic cardiomyopathy: a single-center experience

Abstract

Background: The totally subcutaneous implantable defibrillator (S-ICD) was introduced as a new alternative to conventional implantable defibrillators and is employed worldwide. This system is especially attractive for young patients. However, in patients with hypertrophic cardiomyopathy (HCM), T-wave oversensing may occur. To address the question whether the S-ICD system is suitable for HCM patients, the data of a standard of care prospective single-center S-ICD registry were evaluated.

Methods and results: In the present study, 18 HCM patients who received an S-ICD for primary (n = 14) or secondary prevention (n = 4) and a minimal follow-up duration of 6 months were analyzed. The mean follow-up duration was 31.7 ± 15.4 months. Ventricular arrhythmias were adequately detected in 4 patients (22%). In 7 patients (39%), T-wave oversensing was noticed and led to at least one inappropriate shock in 4 patients (22%). Further adverse events included surgical revision due to a mobile sensing electrode and resulting noise detection as well as one case of early battery failure requiring pulse generator change.

Conclusion: Patients with HCM and S-ICD systems have an increased risk of T-wave oversensing and inappropriate shock delivery. Thorough monitoring as well as exercise tests may help to improve device settings and thereby prevent T-wave oversensing.

Keywords: Device complications; Hypertrophic cardiomyopathy; S-ICD; Sudden cardiac death; T-wave oversensing.