Study design
Between April 2012 and March 2019, we included 708 patients with HFrEF who received a WCD (ZOLL Life Vest ™system, Pittsburgh, USA) at the University Medical Centre in Mannheim, Heidelberg University, Department of Cardiology, University Hospital Frankfurt, Department of Arrhythmias & Invasive Cardiology, St. Georg Hospital Leipzig, and Department of Cardiology, University Hospital of Zurich. This multicenter register is designed as a retrospective cohort registry without any financial support. Patients were treated according to the current European guidelines for heart failure [11].
We divided the collective according to gender (male=579; female=129). Furthermore, all patients were divided into age quartiles for analysis: 161 patients in 14-51 years old group, 375 patients in 52-72 years old group, and 172 patients in 73-91 years old group. Baseline characteristics such as indications for WCD use were gathered. Wear time of WCD and WCD shocks during WCD use were documented. Echocardiographic assessments were collected. The death rate due to a cardiovascular cause during a 2-year-follow-up was evaluated. These data were assessed by chart and/or telephone review at mean 2-year-follow-up. LVEF > 35% led to stop WCD wearing and was recorded as an improvement of the LVEF.
LVEF was calculated by using biplane Simpson’s method, using echocardiography and/or cardiac MRI. This study was executed in compliance with the fifth revision of the Declaration of Helsinki regarding investigations in human subjects and the study protocol was approved by the Ethics Committee in all involved centers [12].