National experience with long-term use of the wearable cardioverter defibrillator in patients with cardiomyopathy.

Abstract

The wearable cardioverter defibrillator (WCD) is generally used for short periods of sudden cardiac death (SCD) risk; circumstances may occasionally result in prolonged use (over 1year). The aim of this study was to determine the benefits and risks of prolonged use in patients with systolic heart failure (HF). ZOLL's post-market US database included adult patients (≥18years) with ischemic and/or non-ischemic cardiomyopathy (ICM, NICM) and at least 1year of use. Cox-regression was used to identify factors associated with survival with WCD use, and reasons for stopping use were entered as time-dependent factors. Among 220 patients, age (mean ± SD) 55.4 ± 14.8years, WCD use 451.4 ± 289.9days, and 67.3% were male and their left ventricle ejection fraction (EF) averaged 20.9 ± 7.2%. Eighty-nine (40.5%) were continuing WCD use at the last follow-up. Thirty-six (16.4%) and 56 (25.5%) patients discontinued WCD use because of EF recovery and implantable cardioverter (ICD) implantation, respectively. Nine patients (4.1%) received appropriate shock therapy for 13 episodes of sustained ventricular tachyarrhythmia with 12 (92.3%) successful shocks. One patient died of refractory ventricular fibrillation. One patient died from sinus bradycardia transitioning to asystole. Eight patients (3.6%) had nine episodes of non-fatal inappropriate shocks. Long-term use of the WCD is safe and effective. Recovery of EF was seen in significant number of patients even after 1year of WCD use.