Long-term clinical outcomes after placement of an implantable cardioverter-defibrillator: does the etiology of heart failure matter?

Abstract

Background: European and American guidelines for the placement of implantable cardioverter‑defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT‑D) in patients with heart failure (HF) remain unchanged despite controversy and ongoing debate on the etiology of HF. However, there are limited data on the long‑term follow‑up in patients who received primary defibrillator therapy with regard to ischemic cardiomyopathy (ICM) and nonischemic cardiomyopathy (NICM). The prognostic significance of the etiology of HF is not well established.

Aims: The aim of the study was to assess the predictive value of the cause of HF.

Methods: A total of 1073 patients with the first implantation of ICD/CRT‑D between January 2009 and December 2013 from the COMMIT‑HF (Contemporary Modalities In Treatment of Heart Failure) registry were selected for the study. Patients were divided into 2 groups depending on the etiology of HF: ischemic (n = 705; 65.7%) and nonischemic (n = 368; 34.3%). The primary endpoint was long‑term all‑cause mortality.

Results: The median follow‑up was 60.5 months. The primary endpoint occurred more often in the ICM as compared with the NICM group (35.7% vs 26.6%; P = 0.008). A higher out‑of‑hospital mortality in patients with ICM tended to be statistically significant (15.5% vs 10.6; P = 0.05). The multivariate analysis revealed that, among others, an ischemic etiology of HF was an independent factor of long‑term mortality (hazard ratio, 1.43; 95% CI, 1.30–1.81; P = 0.003). Other independent predictors for mortality are: age older than 65 years, impaired left ventricular ejection fraction, chronic kidney disease, atrial fibrillation, diabetes mellitus.

Conclusions: In the real‑world population, significantly worse survival of patients with ICM in comparison with those with NICM is observed, and an ischemic etiology of HF is a strong independent predictor of mortality among individuals following the placement of ICD/ CRT‑D.