Are defibrillators less useful in patients with non-ischemic heart disease?

Abstract

Introduction and objective: The benefits of implanted defibrillators in patients with ischemic heart disease (IHD) are well known. However, the evidence is less robust in patients with non-ischemic heart disease (non-IHD). We aimed to determine whether patients with non-IHD have a similar incidence of appropriate shocks and all-cause mortality compared to those with IHD.

Methods: In a retrospective single-center study we analyzed all patients with implantable cardioverter-defibrillators or cardiac resynchronization therapy-defibrillators implanted for primary prevention between 2004 and 2014. The population was divided into two groups: patients with IHD and patients with non-IHD. The composite endpoint was appropriate shock and all-cause mortality.

Results: Two hundred and eighty-one patients were studied, of whom 187 (66%) had IHD. Patients with IHD were older, more frequently male and with more cardiovascular risk factors. Mean follow-up was 55±42 months. Thirty-four patients (18%) with IHD and 20 patients (21%) with non-IHD had an appropriate shock (p=0.64). Eighty-nine patients (47%) with IHD and 36 (38%) with non-IHD died during follow-up (p=0.19). The rate of shocks or death over time was similar in patients with IHD and non-IHD according to Kaplan-Meier survival curve analysis (log-rank p=0.10).

Conclusion: In this population, there were no differences in appropriate shocks or all-cause mortality in the two groups.

Keywords: Appropriate shock; Cardiopatia isquémica; Cardiopatia não isquémica; Cardioversor desfibrilhador implantável; Choque apropriado; Death; Implantable defibrillator; Ischemic heart disease; Morte; Non‐ischemic heart disease.