When is a wearable defibrillator indicated?

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ABSTRACT

Introduction

Wearable cardioverter-defibrillator (WCD) is a novel tool that may be of interest in situations with atransient risk of sudden cardiac death. It offers a temporary and easy to remove protection against malignant ventricular arrhythmias. In this review, the authors describe evidence in literature and different international guidelines and consensus.

Areas covered

The authors searched PubMed, Cochrane Central Register of controlled trials, and Google Scholar for relevant studies and comments.

Expert Opinion

If a WCD is indicated, the observance must be as perfect as possible. Thus, patients need proper education in wearing the WCD.

The temporary use of a WCD is reasonable in patients with a high risk for SCD, even with a low level of evidence with only one randomized clinical trial (VEST), as its disadvantages are limited to a transitory impairment in quality of life and a low risk of inappropriate shock.

Indications are now well accepted: ischemic cardiomyopathy with LVEF below 35% before reassessment, recent onset of NICM or presumed myocarditis with LVEF ≤35% before reassessment, after ICD explant until reimplantation (e.g. infection), and bridge to transplant.

Future guidelines on WCD in the prevention of SCD may be warranted to harmonize clinical practice especially in debated indications..

KEYWORDS:

• Sudden cardiac death
• defibrillation
• wearable cardioverter-defibrillators
• myocardial infarction
• ventricular tachyarrhythmia

Article highlights

• If used, the WCD observance must be as perfect as possible. Thus, patients need proper education in wearing the WCD.

• Disadvantages of WCD are limited to a transitory impairment of quality of life and a low risk of inappropriate shock.

• The results of VEST with nonsignificant results on arrythmic death has challenged nowadays WCD indications in ischemic cardiomyopathy after acute myocardial infarction with LVEF below 35% before reassessment. However, the as-treated and per-protocol analyses confirmed its effectiveness.

• Some other indications are also well accepted even with a low level of evidence: ischemic cardiomyopathy with LVEF below 35% before reassessment, recent onset of NICM or presumed myocarditis with LVEF ≤35% before reassessment, after ICD explant until reimplantation (e.g. infection), and bridge to transplant.

• Some are still debated, and further studies will be needed: tachymyopathy, peripartum cardiomyopathy, during period of risk stratification in cases of syncope/cardiac arrest of unknown origin, potentially dangerous ECG changes with drugs (e.g. QT prolongation), patients with LV assist device, etc. In our opinion, this should be discussed with the patient as the evidence of benefits in such rare situations will be hard to be shown in future studies.

Declaration of interest

L Fauchier is a consultant or speaker for AstraZeneca, Bayer, BMS/Pfizer, Boehringer Ingelheim, Medtronic, Novartis, and Zoll. A. Bisson is a consultant or speaker for Bayer, AstraZeneca, BMS/Pfizer, and Medtronic. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.