Wearable cardioverter defibrillator does not reduce sudden death mortality

15th March 2018

A new study unveiled at the American College of Cardiology in Florida found that wearable heart defibrillator’s reduced the overall risk of early death for heart attack survivors – but not the risk of sudden cardiac death.

The Vest Prevention of Early Sudden Death Trial (VEST) is the first randomised, controlled, trial of the wearable cardioverter defibrillator. It was designed to test whether this device could effectively reduce sudden death in patients who had recently suffered a heart attack and had reduced heart function (defined as a low ejection fraction of 35 percent or less) where the heart wasn't able to pump sufficient blood to the rest of the body, which is indicative of a sizable heart attack.

Wearable cardioverter defibrillators (WCD) devices have become increasingly popular, since this device can be used in a situation where a patient is waiting for an implantable one due to surgical contraindication and prevent the risk of cardiac arrest. It sounds an alarm and can verbally announce the need for medical care if needed. If a life-threatening abnormal heart rhythm is detected, the defibrillator delivers a shock to restore a normal heart rhythm.

While the study did not find a significant benefit in terms of reducing sudden cardiac death, which was the primary endpoint of the study, it did find that the wearable defibrillator was associated with fewer overall deaths.  

Jayne Partridge, Cardiomyopathy UK Support Nurse said: “The LifeVest WCD should not be seen as an alternative to an ICD, but could be used if there is a temporary reason that an ICD cannot be implanted.

WCD’s do have guidelines for use within the United States, however there are no current guidelines for use in the UK at present.

This large randomised controlled trial found that the wearing of the device was associated with fewer deaths and reduced symptoms of shortness of breath amongst the wearer, the study did however demonstrate challenges for the wearer such as the WCD’s bulky nature and itching whilst being worn which reduced patient compliance of the device over the duration of the trial.

Future trials could influence UK guidelines for the use of WCD’s, further trials are likely to follow which could focus on patients with reduced heart function guiding use for people diagnosed with cardiomyopathy with reduced ejection fraction who are unable or unwilling to have an ICD implanted.”