Real-world clinical outcomes of a wearable cardiac device in a high-volume cardiology and cardiothoracic center: a single-center study
E Rexha, A Schlichting, E Veliqi, D Knappe, S Willems, S Hakmi, L KaiserAbstract
Background
The risk of sudden cardiac death (SCD) is increased in patients with newly diagnosed ischaemic (ICM) or non-ischaemic cardiomyopathy (NICM) and a reduced left ventricular ejection fraction (EF) ≤ 35%. In these cases, the wearable cardioverter-defibrillator (WCD) can be considered as a temporary solution to reduce the risk of SCD.
Aim
This study evaluates clinical outcomes in patients who received a WCD, focusing on the incidence of device-detected ventricular arrhythmias (VA) and disease progression, with or without subsequent implantation of an implantable cardioverter-defibrillator (ICD).
Methods
We performed a retrospective analysis of all patients who received a WCD at our heart center from March 2019 to August 2023. Data were collected from WCD records and follow-up visits in our heart failure outpatient clinic.
Results
A total of 244 patients (mean age 60.9 ± 11.7 years; 25.8% female) received a WCD. The WCD was prescribed in 177 (73%) by the cardiology department and in 67 (27%) by the cardiothoracic department. A primary prevention (PP) indication was present in 207 patients (85 %; mean EF 26 ± 8.1%; ICM 46.4 %, EF 27 ± 6.5 %; NICM 53.6 %, EF 26 ± 9.5 %), while 37 patients (15%; mean EF 40 ± 14.6 %; ICM 35.1%, EF 38 ± 15.2 %; NICM 64.9%, EF 41 ± 14.5 %) received the WCD for secondary prevention (SP). The mean initial EF of the total cohort was 28% ± 10.3. Twenty-four patients (9.8%) received the WCD following transvenous lead extraction. The WCD detected ventricular arrhythmias in 11 patients (4.5%; PP n=4, ICM n=4, NICM n=3; SP n=4). Shock therapy was successfully delivered in 4 patients (1.6%; PP n=1, ICM n=1; SP n=3, ICM n=1, NICM n=2). An ICD was implanted in 108 patients (44.3%) after a median of 111 days (VVI-ICD 44.4%, DDD-ICD 10.2%, S-ICD 27.8%, CRT-D 17.6%). Of these, 76 (70.4%) received an ICD for PP (ICM n=31, 40.8%; NICM n=45, 59.2%) and 32 (29.6%) for SP. In the ICD subgroup, 43 patients (39.8%) had ICM and 65 (60.2%) had NICM. A total of 154 patients (62%, mean EF 27 ± 10.1%) were followed in our heart failure outpatient clinic after a median of 53 days; the remaining 38% of the patients were followed externally or were lost to follow-up. Mean EF at first follow-up was 35% ± 10.3, reflecting an improvement of 8 %. At the last follow-up (median 435 days), mean EF increased to 39% ± 12.2%. This represents a total EF improvement of 12%. Of the 154 patients with documented follow-up, 73 (47.4%) underwent ICD implantation (PP n= 53, 71.6% ; SP n= 20, 27.4%). In 81 patients (52.6%), ICD implantation could be avoided, due to an EF improvement above 35%.
Conclusion
Although the WCD was effective, the low arrhythmic event rate suggests that EF alone may not be sufficient for patient selection. Additional risk markers are needed to better identify individuals who benefit from WCD therapy. Furthermore, this analysis demonstrates the importance of close and structured follow-up.