Wearable defibrillators, an effective alternative for children with arrhythmias

Wearable cardioverter defibrillators (WCDs) may be a safe and effective alternative to the surgically implanted device for the treatment of ventricular arrhythmias in pediatric patients that otherwise could lead to sudden cardiac death in them, according to a new study. WCDs are vest-like devices that deliver electric shocks to interrupt a dangerous heart rhythm.

The study, published in the journal Circulation: Arrhythmia and Electrophysiology, is the first to describe appropriate therapy with a wearable cardioverter defibrillator in a pediatric population.

David Spar, assistant professor of pediatrics at the University of Cincinnati, and colleagues conducted the study to examine the effectiveness, safety, and compliance of the WCD in the identification and treatment of life-threatening ventricular arrhythmias in pediatric patients.

Sudden cardiac arrests in children are usually caused by heart abnormalities that the child is born with. It is often triggered by an electrical malfunction that results in a rapid heartbeat that causes ineffective pumping of the heart. With its pumping action disrupted, the heart cannot pump blood to the brain, lungs and other organs, and this can result in death if the heart's rhythm is not restored or corrected.

Surgically implanted cardioverter defibrillators -- the main therapy for children at high-risk for sudden cardiac death due to heart rhythm disorders, known as arrhythmias, are effective in averting deaths from potentially lethal heart rhythms, but invasive surgery or prolonged hospitalization is required.

However, many young patients are not good candidates for these surgically implanted devices because they need only a temporary "bridge" to help their heart. For example, if they are waiting for a heart transplant, are a newly diagnosed heart failure patient who is recovering cardiac function or if they have an infected implanted cardioverter defibrillator, they wouldn't be good candidates, Spar explained.

"Our results, which stem from the largest study to date among children in the United States using wearable cardioverter defibrillators, suggest that these external devices can help save the lives of children who are at the time, not good candidates for surgically implanted defibrillators because of their medical condition," said Dr. Spar.

For the study, all U.S. pediatric patients <18 years who wore a WCD, from 2009 to 2016 were retrospectively reviewed. In total, 455 patients were identified. The median age was 15 (3–17) years, median duration of WCD use was 33 (1–999) days and median patient wear time was 20.6 (0.3–23.8) hours per day. The population was divided into 2 groups: (1) patients with an implantable cardioverter-defibrillator problem, n=63 and (2) patients with a nonimplantable cardioverter-defibrillator problem, n=392. Wear time per day was >20 hours in both groups. Wear duration was shorter in the implantable cardioverter-defibrillator problem group, 26 days versus 35 days, P<0.05.

Key Results:

• There were 7 deaths (1.5%); all not wearing WCD at time of death.


• Eight patients (1.8%) received at least 1 WCD shock treatment to interrupt a dangerous heart rhythm.


• Of the 6 patients (1.3%) who had appropriate therapy, there were 7 episodes of either polymorphic ventricular tachycardia or ventricular fibrillation with a total of 13 treatments delivered.


• In all cases, the dangerous heart rhythm was successfully interrupted, normal heart rhythm restored and the patient survived.

Even though wearable cardioverter defibrillators were approved by the U.S. Food and Drug Administration for use in pediatric patients in 2015, data about their safety and efficacy in children has remained limited. This gap in knowledge has been particularly troublesome in how effective the device would be in younger patients in treating dangerous arrhythmias. If effective, the wearable cardioverter defibrillator could avoid prolonged hospitalizations while still offering arrhythmia protection, researchers said.

"The WCD has overall adequate compliance with appropriate wear times and wear durations in pediatric patients. The WCD is safe and effective in treating ventricular arrhythmias that can lead to sudden cardiac death in pediatric patients," concluded the authors.