The findings of new research suggests that wearable defibrillators do not appear to provide any extra protection against death for patients who recently suffered a heart attack.
In a study published in the New England Journal of Medicine on September 27, researchers who were part of the VEST clinical trials indicate that they failed to find a lower rate of heart-related deaths among patients who were given wearble cardioverter-defibrillators up to three months following a heart attack.
Patients with a low ejection fraction who have recently suffered a myocardial infarction are at a higher risk of death. While such patients may eventually be implanted with a heart device, implantable cardioverter-defibrillators are contraindicated until 40 to 90 days after a heart attack.
In this new study, researchers sought to see if the wearable devices would reduce the risk of death among those patients. They conducted a clinical trial known as VEST, which was funded by the National Institutes of Health and Zoll Medical. The study involved 2,302 participants, 1,524 assigned to the device group and 778 assigned to a control group.
According to the findings, arrhythmic death occurred in 1.6% of patients wearing the defibrillators, compared to 2.4% in the control group. Of the 48 in the device group who died, 12 were wearing the defibrillator at the time of death. The device delivered appropriate shocks to 20 participants in the device group, or about 1.3%, and delivered inappropriate shocks to nine study participants, or 0.6% of the device group.
“Among patients with a recent myocardial infarction and an ejection fraction of 35% or less, the wearable cardioverter–defibrillator did not lead to a significantly lower rate of the primary outcome of arrhythmic death than control,” the researchers concluded.
Earlier this year, Zoll Medical, one of the backers of the study, had to issue a Zoll LifeVest 4000 recall after it was discovered that the devices may stop supplying life-saving shock treatments. At least one fatality was linked to the recall, which sparked an FDA safety communication on January 17.
The recalled vests are wearable cardioverter defibrillators used to treat life-threatening abnormal heartbeats in adults and children that are at risk of sudden-cardiac arrest and not candidates for an implantable defibrillator.
The devices are designed to continuously monitor the patient’s heart and, in the event a fast, or life-threatening heart rhythm is detected, will deliver a shock treatment to restore the patient’s heart beat to a normal rhythm.