The wearable cardioverter defibrillator (WCD) is intended to provide protection against sudden cardiac death in high-risk patients. In 2018, the first RCT was available (VEST/ Prevention of Early Sudden Death Trial), showing no reduction in sudden cardiac death when compared to medical therapy alone. Due to the fact that VEST was limited by poor compliance, it is still unclear whether anticipated patient-relevant benefits of using the WCD is supported by scientific evidence.

The project at hand aimed at synthesising the current available evidence regarding the use of the WCD: An update systematic review regarding the effectiveness and safety of the WCD was performed. The best available RCT evidence still consists of VEST solely. Low certainty evidence derived from one RCT (n=2,348) indicated that WCD therapy might not be associated with a clinical benefit in arrhythmic mortality in post-myocardial infarction (MI) patients with an ejection fraction of ≤35%.
Six new observational studies were identified, yielding 11 observational studies meeting our inclusion criteria (range of enrolled patients: 102-2,000). New observational studies indicate that compliance with WCD is well above 20 hours per day, with poor compliance being a major limitation of the only available randomised evidence for WCD use. Most of the evidence is however observational and consists of studies including mixed-populations in the analysis, leading to the inability to draw firm conclusions on indication-specific utility of the WCD.

In the absence of comparative effectiveness evidence, more RCT data are needed to justify continuing or expanding the use of WCD therapy in Austria.