DENVER — A wearable cardioverter defibrillator appears to provide safe, continuous arrhythmia monitoring and automatic defibrillation for use as a bridging strategy, according to 18-month data from the WEARIT-II Registry.
WEARIT-II is the first national registry of US patients prescribed the wearable cardioverter defibrillator (LifeVest, Zoll Medical). It was designed to provide prospective data on the safety and efficacy of the LifeVest as a bridging strategy in a real-world setting. Outcome measures included clinical and arrhythmic events; appropriate and inappropriate device discharge; and need for ICD after device discontinuation.
Researchers studied 882 patients who wore the LifeVest for 2 to 6 months from August 2011 to March 2013. The patients’ mean age was 61 years, 31% were women and mean left ventricular ejection fraction was 25%. The majority (87%) presented with acquired dilated cardiomyopathy and the rest presented with inherited arrhythmias.
On average, patients wore the LifeVest for 81 days, for 21 hours each day.
“Compliance to the LifeVest was relatively high,” Ilan Goldenberg, MD, research professor at University of Rochester Medical Center, New York, said during a scientific session at the Heart Rhythm Society’s Annual Scientific Sessions.
During the follow-up period, 70 sustained ventricular tachyarrhythmic events occurred in 21 patients. One-quarter of the events were treated with appropriate shocks from the device and the rest were terminated spontaneously because patients intentionally withheld shock therapy with a response button on the wearable device. The rate of inappropriate wearable cardioverter defibrillator therapy (0.3%) and death (0.5%) were low, according to a press release. Three patients died while wearing the LifeVest and one death was related to asystole while not wearing the device.
Patients with inherited arrhythmias had a higher rate of arrhythmic events compared with those with acquired heart disease. In the patients with acquired heart disease, those with ischemic cardiomyopathy had significantly higher rates of arrhythmic events, including sustained ventricular tachycardia, nonsustained ventricular tachycardia and AF, according to the release.
Following termination of the LifeVest, more than 40% of patients did not receive an ICD because of improvements in EF. Rate of improved EF was significantly higher among patients with acquired heart disease. The highest rate of ICD use was among patients who received appropriate therapies from the LifeVest and lowest among those with no arrhythmias detected by the device, according to data presented.
“Our data indicate that in the real-world setting, the LifeVest can be safely used to bridge the decision for therapy in high-risk populations, including those with acquired inherited congenital heart disease,” Goldenberg said. “The LifeVest allows the safe termination of life-threatening arrhythmic events, the avoidance of unnecessary therapies for non-life-threatening arrhythmias with a very low rate of inappropriate therapies.”
The WEARIT-II Registry is ongoing and has been extended to Europe and Israel. – by Deb Dellapena
For more information:
Goldenberg I. LB02-02. Presented at: Heart Rhythm Society’s Annual Scientific Sessions; May 8-11, 2013; Denver.
Disclosure: Goldenberg reports receiving grants from Boston Scientific and Zoll Medical.