Long-term use of the wearable cardioverter-defibrillator: prolonging life or prolonging indecision?

Abstract

Predicting future risk is difficult. Predicting sudden cardiac death (SCD) is a particular challenge, given its finality, suddenness, inherent unpredictability, and medicolegal ramifications. Yet the task of prognosticating SCD risk is often thrust upon electrophysiologists in the setting of a new cardiomyopathy.The implantable cardioverter-defibrillator (ICD) mitigates SCD risk in patients at increased risk for ventricular arrhythmias. Its effectiveness is largely not questioned [1], although the appropriate population who should receive an ICD is still being refined [2]. The wearable cardioverter-defibrillator (WCD) was approved by the U.S. Food and Drug Administration in 2001 as a temporary device that continuously monitors cardiac rhythm and is highly effective in terminating potentially lethal arrhythmias [3][4][5]. It has been marketed for use in patients deemed at elevated risk of SCD from ventricular arrhythmias in whom a permanent ICD is either contraindicated or under consideration. To date, there have been several publications describing its use in clinical registries [5,6], national experiences [4,7], and single-center studies [8], primarily as a short-term means of mitigating risk while patients undergo more comprehensive evaluation or titration of medical therapy. There are, at present, no currently published randomized WCD clinical trials demonstrating a mortality benefit.In this issue of the Journal of Interventional Cardiac Electrophysiology, Lamichhane et al. [9] describe the U.S. experience with long-term WCD use in patients with ischemic or non-ischemic cardiomyopathy, primary or secondary prevention indication, no prior ICD, and LVEF ≤35%. Remarkably, 220 patients were prescribed with the WCD for ≥1 year, and the median number of actual use days was 394. Despite such prolonged use, over half of all the patients wore the WCD >80% of the day.Long-term WCD use has not been heretofore described in the literature. In the present study, some reasons cited for longterm use rather than ICD implantation included continued optimization of medical therapy (7.7%), non-compliance for follow-up (10%), patient postponement or unwillingness to have an ICD (16.8%), ongoing evaluation for an ICD (34.5%), and contraindication to an ICD because of cancer, poor prognosis, or vascular access issues (23.2%). The incidence of appropriate shocks was 4.1%; 9 of the 220 patients received a shock, 3 of whom already had prior sustained ventricular arrhythmias (i.e., secondary prevention indication). Of the remaining 6 (2.9%) primary prevention patients, 4 had ischemic cardiomyopathy and 2 had non-ischemic cardiomyopathy. One non-ischemic patient had reported WolffParkinson-White syndrome, and another had chronic lymphocytic leukemia.The WCD has proven effectiveness in terminating tachyarrhythmias. In this study, the WCD successfully terminated 92% of VT/VF episodes. However, there is no mention of cost, either personal or monetary. On a psychosocial level, wearing the WCD consistently for a year requires tremendous pers...

Extended Use of the Wearable Cardioverter-Defibrillator: Which Patients Are Most Likely to Benefit?

“…So far, the optimal timing of ICD implantation in NICM patients is still under debate. Whether prolonged WCD use in NICM patients is an option to prevent unnecessary ICD implantations, while minimizing the risk of sudden cardiac death remains an open question [34–36]. Hopefully, the currently recruiting HF-Opt trial (NCT03016754) examining EF improvement beyond 90 days of WCD use will hopefully provide some additional information on this subject.…”