The wearable defibrillator: a most affordable vest
Neth Heart J
The wearable defibrillator: a most affordable vest
J. R. de Groot 0 1
0 Heart Center, Department of Cardiology, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands
1 J. R. de Groot
-
Published online: 13 April 2017
© The Author(s) 2017. This article is available at SpringerLink with Open Access.
The implantable cardioverter-defibrillator (ICD) has
become a cornerstone in the prevention of sudden cardiac
death in patients with ischaemic and non-ischaemic
cardiomyopathy, as well as in survivors of idiopathic
ventricular arrhythmias and carriers of a genetic arrhythmia
syndrome. Current guidelines recommend ICD
implantation in patients with a left ventricular ejection fraction
35%, despite optimal medical treatment for 3 months,
and at least 40 days after myocardial infarction or
revascularisation [
1
].
These delays have been implemented because ejection
fraction may improve over time upon treatment, and ICD
implantation shortly after myocardial infarction has been
demonstrated futile, mainly due to death as a consequence
of pump failure. As physicians, we can accept this.
However, the fact that our patients nonetheless have a high risk
of preventable arrhythmic death in the meantime, is harder
to accept. The same risk applies to patients in whom an
infected ICD system has been extracted, who face long-term
antibiotic treatment during which no new device can be
implanted. That is why several strategies are employed to
overcome the issue of unprotected arrhythmia risk, among
which monitored hospitalisation and the temporary use of
a wearable cardioverter-defibrillator (WCD). In a European
Heart Rhythm Association (EHRA) survey of WCD use in
European countries, Lenarczyk et al. describe that less than
50% of the centres responding used the WCD [
2
]. The most
important barriers were reimbursement issues, followed by
patient compliance, and only 55% of centres reported a
patient compliance of >90% per day.
In this issue of the Netherlands Heart Journal, Quast and
colleagues report on the experience with a wearable
defibrillator in two high-volume Dutch centres [
3
]. The report
follows the initial description of the first experience with
this technology in the Netherlands [
4
]. The majority of the
patients Quast et al. report on are patients with newly
diagnosed cardiomyopathy without a sufficiently long duration
of optimal medical therapy, whereas in the remainder the
WCD was used as a bridge to implantation in patients with
a contraindication for immediate implantation due to
infection or planned radiotherapy. During a median wearing
time of 79 days, compliance was excellent with 23.3 h/day.
Two patients received an appropriate shock, and one an
inappropriate shock (all with ischaemic cardiomyopathy).
This translated into an annual appropriate and
inappropriate shock rate of 13.6 and 6.7%, respectively. There were
no unsuccessful treatment episodes.
Can the description of a relatively low number of
patients, with an established therapeutic intervention,
contribute to our understanding? And what do the real-life data
from the Netherlands tell us? In an era of limited health-care
system funds on the one hand, and indications for ICD
implantation, particularly driven by low ejection fractions
(irrespective of the cause), on the other, the data that Quast and
colleagues present teach us two important lessons. First, the
patients concerned were indeed at a very high risk of sudden
arrhythmic death. Not only was the reported annual rate of
appropriate therapy for ventricular fibrillation considerably
higher than in most contemporary studies, but also one of
the three patients who refused ICD implantation after WCD
treatment subsequently died from sudden cardiac death
during follow-up (median follow-up was 1.6 years). These
numbers justify any form of protection against
arrhythsubcutaneous ICDs, the appropriate shock rate was
considerably lower than in the patients Quast et al. describe [
5
].
This does not imply that the indication criteria for ICD
implantation were less strict in those patients, nor can it be
concluded that all patients awaiting ICD implantation are at
similar risk of having arrhythmias as the patients described
by Quast et al. Postponing ICD implantation beyond the
guideline-directed time periods, however, clearly prevents
unnecessary implantations and with that, future
device-related complications. It seems safe to conclude, therefore,
that the WCD is an effective and affordable bridge to
destination therapy.
Funding ZonMw (NL) (016.146.310)
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