ICD Implantation May Increase Heart Failure Admissions in Patients with Left Ventricular Systolic Dysfunction Who Demonstrate Reverse Remodeling

Abstract

In patients with an implantable cardioverter defibrillator (ICD), worsening heart failure (HF) is an important cause of death. Patients who demonstrate reverse remodeling (RR) have fewer admissions for HF, however, the effect of an ICD implant on HF outcomes in this group is not known. The aim of our study was to evaluate whether an ICD implant affects the likelihood of heart failure hospitalizations in patients who subsequently demonstrate RR compared to those who do not. Consecutive patients (n = 600) with newly documented LVEF ≤ 0.35 with at least one follow up echocardiogram ≥ 3 months later were identified. We excluded patients with ICDs implanted prior to enrollment and for secondary prevention (n=72), and those with a bi-ventricular ICD (n= 25). RR was defined as an increase in LVEF to > 0.35. Patients who demonstrated reverse remodeling (RR group) (n = 246) and those who did not (No-RR group) (n = 257) were evaluated. In each group, the subset with and without an ICD were compared for the likelihood of a future HF hospitalization using Cox-proportional hazard analysis. In patients who had an ICD, HF admissions prior to receiving the ICD were censored. Mean follow up period was 27 months. Overall, patients in the RR group compared to the No-RR group had fewer annualized HF admissions per patient (0.15 vs. 0.43, p< 0.001). In the No-RR group, survival free-from-HF admissions was similar between the ICD (n= 71) and No ICD (n = 186) subgroups (HR 1.0; 95% CI 0.7- 1.6; p NS). However, in the RR group, patients in the ICD subgroup (n= 13) had increased HF admissions demonstrated by a trend towards reduced survival-free-from-HF admissions (HR 0.54; 95% CI 0.2-1.4; p = 0.07) when compared to the No ICD subgroup (n = 233). In patients with LV systolic dysfunction without reverse remodeling, HF admissions were unaffected by ICD implantation. On the contrary, in patients who demonstrated reverse remodeling, there was an important trend towards increased HF admissions following ICD implantation. This trend is concerning and needs further evaluation in a larger population.