Introduction:

Every year the number of newly diagnosed patients with heart failure with reduced ejection fraction (LV-EF <35%) is app. 300,000 in Germany alone. Guideline directed medical therapy has proven to reduce mortality and rehospitalization regardless of the disease’s etiology and has the goal to reduce clinical symptoms by increasing the ejection fraction. Patients with a transient risk of ventricular tachycardia and sudden cardiac death because of low ejection fraction (LV-EF <35%) can be protected by a defibrillator vest (LifeVest®, Fa Zoll). The defibrillator vest provides the ability to detect and terminate ventricular arrhythmias during Guideline Directed Medical Therapy (GDMT).

Methods:339 patients with an EF <35% were fitted with a wearable cardioverter defibrillator (WCD) between August 2017 and September 2020. The average patient age was 63.2 years (SD +11,9 years). 129 pts (38%) had ICM, 196 (54%) had NICM (incl 66 pts [19%] with DCM and 51 pts [15%] with Myocarditis), 14 pts (4%) had other indications (e.g. Tachycardiomyopathy). 21 pts (6%) had an LV-EF of less than 16%, 130 pts (38%) between 16-25%, and 183 pts (54%) between 26-35%. For all patients GDMT started at baseline. Reevaluation of the left ventricular ejection fraction (LV-EF) was carried out by transthoracic echocardiography at week 4 and 8. Upon discharge uptitration in the outpatient setting was recommended. We analyzed baseline medication as per GDMT and its up-titration to the maximum dosage tolerated by the patient. 

Results:Baseline medication started in the in-hospital setting included treatment with Beta-Blocker 327 pts (96,5%), ACE-inhibitors/Angiotensin/ARNI 283 pts (83,5%) and Mineralcorticcoid receptor antagonists (MRA) 334 pts (88,4%). Up-titration has occurred in all groups at a rate of 82,3%, 91,1% and 81,0% after 4 weeks and 64,7%, 50,3%, 66,3% after 8 weeks respectively (Figure 1).  After 8 weeks 171 pts (50,4%) had an EF increase of 5% or more (mean 14,2%). In 122 pts 35,9% the EF recovered to >35%. NICM patients had a slightly higher increase in average EF than patients with ICM (14,6% and 13,3% respectively) After 8 weeks 35,9% (n=122) recovered to an LVEF >35%. 101 pts (29,8%) received an implantable Cardioverter Defibrillator (ICD) because of persistently reduced systolic LV-EF <35% whereas 232 pts (68,4%) did not receive a device. The rate of ICD recipients was slightly higher in the group that received any uptitration though not statistically significant (65,1% vs. 67,4%). In less than 1% of the patients a reduction of GDMT occurred.  

Discussion:Due to the defibrillator vest, patients with ICD indication can be protected transiently (e.g. for medicinal heart failure therapy) from ventricular arrhythmias. Consequent start of GDMT reduces the need for ICD implantation. Interestingly we found no significant difference in LV-EF recovery between the group in which GDMT was uptitrated at week 4 and 8 and the group with no GDMT uptitration. which may depend on the high number of GDMT at the timepoint of discharge from hospital or on the low case count in our study, as we would generally expect the improvement of LV-EF depending on the maximum GDMT dose. After 3 months, the number of primary prophylactic ICD indications is reduced to less than a third. Our results show, that the LV-EF improvement is depending on strict adherence to GDMT from the point of discharge and does not depend on the underlying reason for heart failure.