Wearable cardioverter defibrillators

Topic Status Complete

Wearable cardioverter defibrillators for people at risk of cardiac death

Outcome of the appraisal


The evidence supports the adoption of wearable cardioverter-defibrillators, in some but not all, adult patients at high risk of sudden cardiac death.
For patients who require an implantable cardioverter-defibrillator to be explanted and there is a delay to re-implantation, the use of wearable cardioverter-defibrillators is considered
clinically and cost effective, and HTW supports their use for this indication.
For patients in whom there is an unavoidable delay in decision-making about the possible need for a permanent implantable cardiac defibrillator, there is uncertainty around the benefits of
wearable cardioverter-defibrillator devices and they do not appear to be cost-effective. HTW does not recommend routine use for this population.

Why was this topic appraised?


The most common causes of sudden cardiac death are rhythm disturbances originating from the main pumping chambers of the heart, the ventricles. Abnormal electrical activity in the
ventricles can lead to ventricular fibrillation or ventricular tachycardia, and these are linked to a number of different cardiac diseases. The risk of developing these rhythm disturbances can be reduced with drug treatments but not eliminated.

Standard additional treatment in some patients is the placement of an implantable cardiac defibrillator (ICD) in the heart that is able to deliver an electric shock to the inside of the heart to terminate life-threatening ventricular rhythm disturbances should they occur.
Situations may arise, however, when people are at high risk of sudden cardiac death and implantation of a permanent ICD may be either not necessary or desirable. For example, following an acute event such as a heart attack or an episode of acute inflammation of the heart muscle, the risk of sudden death may diminish with time, as the heart recovers and medication is optimised. Under these circumstances, a permanent ICD may prove not to be necessary but a period of uncertainty is unavoidable. Similarly, in patients who already have an ICD in place and the system becomes infected and needs to be extracted, there is an obligatory period of time during which the infection needs to be treated before it is safe to implant a replacement device. All of these situations expose people to relatively short periods of time during which the risk of sudden cardiac death remains.

The wearable cardioverter-defibrillator is a vest-like device worn in direct contact with the skin that continuously monitors heart rhythm and automatically delivers an external electric shock, within one minute, of an arrhythmia being detected. The wearable-cardioverter defibrillator is intended to be worn as an interim measure during a period of recovery and optimisation of medication or while awaiting ICD implantation/re-implantation.
This topic was submitted to HTW by the Welsh Health Specialised Services Committee (WHSSC)

Plain language summary


People who have a problem with their heart, leading to an irregular heart rhythm, may be at high risk of their heart stopping suddenly. This population may include people with cardiomyopathy, heart failure, inflammation of the heart, coronary artery disease, valvular heart disease, certain genetic conditions affecting the heart, certain heart conditions in pregnancy, and people who have had a recent heart attack whose heart continues not to pump blood effectively.

To prevent further instances of irregular heart rhythm and heart problems, doctors may recommend a period of time where people take certain medicines. For some people, these medicines may help to resolve the issue. For others with a permanent high risk of their heart stopping suddenly, doctors may recommend longer term solutions, like implantable cardioverter defibrillators (ICD) that are fitted permanently in people’s chest. There is also a group of people who have had an ICD removed who are also at high risk. While people wait for medicines to work or for an ICD to be fitted, they are at a high risk of death. Currently, some patients may be monitored in hospital during this time and wearable cardioverter-defibrillators may help manage this risk.

Wearable cardioverter-defibrillators are devices that continuously monitor heart rhythm and automatically deliver an electric shock, within one minute, when certain irregular heart rhythms are detected. They are worn externally, like a vest, against the skin. Wearable cardioverter-defibrillators are interim measures, not intended for long-term use. They must be worn all of the time, except when the user is bathing. Because they are wearable, people can take them home to monitor their condition, meaning that some people may not need to stay in hospital whilst awaiting an ICD or for medication to work. Currently, the LifeVest is the only wearable-cardioverter defibrillator available for use in the UK.

Health Technology Wales looked for evidence on the clinical and cost effectiveness of wearable cardioverter-defibrillators for adults at high risk of sudden cardiac death. The evidence supports the adoption of wearable cardioverter-defibrillators, in some but not all, adult patients at high risk of sudden cardiac death. 



Topic Exploration Report

TER355 05.2022

Evidence Appraisal Review

EAR048 11.2022


GUI048 11.2022


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