Significantly less inappropriate shocks in ischemic patients compared to non-ischemic patients: The S-ICD experience of a high volume single-center

Background: The subcutaneous cardioverter-defibrillator (S-ICD) continues to be preferentially used in relatively young patients, with less advanced heart disease. Objective: We, therefore, studied the short and long-term efficacy and safety of the S-ICD in subgroups of patients, which are underreported at present. Methods: A total of 218 patients between November 2010 and February 2019 undergoing S-ICD with a follow up of at least 6 months implantation were included in a prospective registry. Mean follow up was 38 months. Results: The most common indication for S-ICD implantation was ischemic cardiomyopathy (n = 106, 49%). Complication rate needing invasive intervention was 9% (n = 21). Appropriate shock rate in patients with an S-ICD was 3.5%/year. A total of 30 inappropriate shocks (IAS) occurred in 19 patients (8.7%; 2.7%/year). The proportion of appropriate and inappropriate shock rates in patients with different cardiomyopathies shows remarkable variances. There were significant more IAS (3.6%/year vs. 1.7%/year, p =.048) in patients with non-ischemic cardiomyopathy versus patients with ischemic cardiomyopathy. Multivariate analysis identified, besides type of cardiomyopathy, atrial fibrillation (AF) as predictor for IAS. Conclusion: In this real-world prospective registry we analyzed S-ICD performance in the more traditional ICD patient. Patients with ischemic cardiomyopathy had significantly less inappropriate therapy compared to patients with non-ischemic cardiomyopathy and appear to be appropriate patients for this type of device.