gms | German Medical Science

Background: Sudden cardiac arrest (SCA) is the most common cause of death in patients with coronary artery disease. Mostly, ventricular tachycardia (VT) and ventricular fibrillation (VF) are the underlying etiology of SCA, which is claimed to be treated by a novel defibrillation therapy, a wearable cardioverter defibrillator (WCD 4000, LifeVest^®, CE-marked in 2011).

The assessment, performed within the European Network for HTA (EUnetHTA), aimed to provide valid data on clinical effectiveness and safety of the WCD. Furthermore, the project intended to elicit patients’ views on aspects regarding their cardiac disease and the WCD therapy as well as to identify neglected outcomes.

Methods: A synthesis of evidence on the basis of a systematic literature search in Medline via Ovid, Embase, The Cochrane Library, and CRD databases was performed. The search was complemented by a “Scopus search” (i.e. citation tracking) and handsearch (web-search).

A face2face semi-structured Focus group interview was performed with 5 cardiac disease patients in the scoping phase.

Results: Many retrospective registry studies (> 15) were identified, majority of which are based upon manufacturer’s datasets, and no prospective controlled trials were found. No study fulfilled the study inclusion criteria for evaluation of effectiveness. With regard to safety, 5 studies were included, but the quality of the body of evidence was very low. Adverse events (AEs) reported were (in % of patients): skin rash and itching (6%), false alarms (14%), palpitations, lightheadedness and fainting (9%) and discontinuation due to comfort and lifestyle issues (16-22%). Serious adverse events (SAEs) that occurred were inappropriate shocks (0-2%) and unsuccessful shocks (0-0.7%). Frequency of SAEs leading to death was 0-0.3%.

Participants of the Focus group reported that experiencing a sense of security was crucial to them. WCD therapy was not considered a long-term option due to expected restrictions in living a ‘normal’ and secured life.

Conclusion: According to the published data, no statement can be made about the device effectiveness – further research is needed. Studies suggest that the WCD could be a relatively safe intervention in the short to medium term. However, more data and more adequate reporting of AEs and SAEs are needed in order to establish the device safety. In particular, more data is needed for specific risk stratification of high risk patients in order to further narrow down the wide range of indications for WCD use.