Use of the wearable cardioverter-defibrillator – the Swiss experience

Abstract

INTRODUCTION: Sudden cardiac death caused by malignant arrhythmia can be prevented by the use of defibrillators. Although the wearable cardioverter defibrillator (WCD) can prevent such an event, its role in clinical practice is ill defined. We investigated the use of the WCD in Switzerland with emphasis on prescription rate, therapy adherence and treatment rate. MATERIALS AND METHODS:The Swiss WCD Registry is a retrospective observational registry including patients using a WCD. Patients were included from the first WCD use in Switzerland until February 2018. Baseline characteristics and data on WCD usage were examined for the total study population, and separately for each hospital. RESULTS: From 1 December 2011 to 18 February 2018, a total of 456 patients (67.1% of all WCDs prescribed in Switzerland and 81.1% of all prescribed in the participating hospitals) were included in the registry. Up to 2017 there was a yearly increase in the number of prescribed WCDs to a maximum of 271 prescriptions per year. The mean age of patients was 57 years (± 14), 81 (17.8%) were female and mean left ventricular ejection fraction (EF) was 32% (± 13). The most common indications for WCD use were new-onset ischaemic cardiomyopathy (ICM) with EF ≤35% (206 patients, 45.2%), new-onset nonischaemic cardiomyopathy (NICM) with EF ≤35% (115 patients, 25.2%), unknown arrhythmic risk (83 patients, 18.2%), bridging to implantable cardioverter-defibrillator implantation or heart transplant (37 patients, 8.1%) and congenital/ inherited heart disease (15 patients, 3.3%). Median wear duration was 58 days (interquartile range [IQR] 31-94) with a median average daily wear time of 22.6 hours (IQR 20-23.2). Seventeen appropriate therapies from the WCD were delivered in the whole population (treatment rate: 3.7%) to a total of 12 patients (2.6% of all patients). The most common underlying heart disease in patients with a treatment was ICM (13/17, 76.5%). There were no inappropriate treatments.CONCLUSION: The use of WCDs has increased in Switzerland over the years for a variety of indications. There is high therapy adherence to the WCD, and a treatment rate comparable to previously published registry data.

Wearable Cardioverter–Defibrillator-Measured Step Count for the Surveillance of Physical Fitness during Cardiac Rehabilitation

“…The wearable cardioverter-defibrillator (WCD) offers protection from sudden arrhythmic death in patients at increased risk, but before implantable cardioverter defibrillator (ICD) implantation is warranted [15,16]. Patients enrolled in CR clinics after an acute cardiac event are therefore frequently candidates for its use.…”

Experience with a Wearable Cardioverter-defibrillator in 436 Patients

“…Interventions and Physiologic Parameters in Patients According to Automatic Implantable Cardioverter-defibrillator Status Switzerland13 including 456 patients reported an appropriate shock rate of 3.7% and an AICD rate of 46.5%. Recently, a study by Heimeshoff et al,14 which included 100 patients who had undergone cardiac sur gery, found VT episodes at a rate of 10% and lifesav ing shocks at a rate of 3%.…”

Handling SCD risk in adult congenital heart disease: Should we InVEST in the WCD?

“…This needs to be interpreted with caution due to the limited sample size; it is likely that studies with greater numbers would reveal a fair proportion of appropriate therapies, given the significant arrhythmia risk in complex CHD substrates [ 1 , 5 ]. However studies encompassing adequate number of CHD patients are difficult to perform; in a nation-wide Swiss WCD registry, only 3.3% had CHD, with no appropriate therapies recorded during the study [ 6 ]. In another WCD study confined to CHD and inherited arrhythmia syndromes, again no appropriate therapies were seen in the 43 CHD patients studied; however the mean follow-up was only 27 days [ 7 ].…”

“…Encouragingly, there were no inappropriate therapies in the present study. Again, although the small number of patients studied precludes firm conclusions, other observational studies have also shown low rates of inappropriate shocks from the WCD [ 6 , 8 ]. A useful feature of the WCD is the occurrence of an audible alarm on arrhythmia detection and a patient response button which allows a shock to be aborted in case of a well-tolerated arrhythmia or inappropriate detection, thus affording patients a sense of confidence and control.…”