The WEARIT-II prospective registry of more than 2,000 US patients has found over 90% survival rate at one-year in patients prescribed with the LifeVest wearable defibrillator (Zoll). Patients who experienced ventricular tachycardia/ventricular fibrillation (VT/VF) during use of the wearable defibrillator also had a 92% survival rate at one-year follow-up. There was no difference in survival between patients with ischaemic or non-ischaemic cardiomyopathy.
Valentina Kutyifa (University of Rochester Medical Center, Rochester, USA) presented the follow-up of WEARIT-II during a late-breaking session at CARDIOSTIM-EHRA EUROPACE (8‒11 June, Nice, France).
The wearable defibrillator, explained Kutyifa, can be temporarily used for further risk stratification for an implantable cardioverter defibrillator (ICD) in patients with low ejection fraction. Possible clinical scenarios include post myocardial infarction, patients following coronary revascularisation, in new onset dilated cardiomyopathy patients, in those with high risk for sudden cardiac death until stabilisation or in patients with inherited arrhythmic or congenital disorders with a temporary high risk for sudden cardiac death.
Previously reported short-term results from the WEARIT-II registry demonstrated a high sustained VT/VF event rate, with 22 events per 100 patient-years—2.1% of patients had a VT/VF event. One in 14 patients experienced a clinically meaningful arrhythmia requiring intervention while wearing the wearable defibrillator. These results also showed that the most common reason for no ICD implantation following a typical three months of wearable defibrillator use was improvement in ejection fraction and, most importantly, the arrhythmias detected by the wearable cardioverter defibrillator facilitated the decision for an ICD implantation.
Data collection, Kutyifa said, occurred from August 2011 until February 2016 and included 805 (40.3%) patients with ischaemic cardiomyopathy, 927 (46.4%) non-ischaemic cardiomyopathy patients and 268 (13.4%) patients with congenital or inherited cardiac disease at high risk for sudden cardiac death. The patients were on average 60-years old and about 30% of them were female.
At one-year follow-up, all-cause mortality was 4%, three deaths happened when patients were using the wearable cardioverter defibrillator. Thirty two per cent of the deaths were cardiac related, 17% were non-cardiac related and 47% are unknown.
When looking at all-cause mortality by disease aetiology, Kutyifa said, it was found that patients with congenital or inherited cardiac disease had a trend towards higher rate of mortality as compared to ischaemic and non-ischaemic patients.
Kutyifa also highlighted that ischaemic and non-ischaemic patients presented with similar survival rates with or without an implanted ICD following wearable defibrillator use, while congenital inherited patients had a higher mortality rate without ICD. Therefore, she concluded: “Short-term use of the wearable defibrillator seems to be an appropriate management strategy for risk stratification for most patients at high risk for sudden cardiac death.”
The wearable defibrillator is included in the 2015 European Society of Cardiology guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death, and has received formal recommendations in the 2016 American Heart Association Science advisory for the wearable cardioverter defibrillator, with endorsement from the Heart Rhythm Society.