Predictors of ventricular tachyarrhythmia in patients treated with a wearable cardioverter defibrillator: data from an international multicentre registry

F. Kreimer (Münster)¹, K. Koepsel (Bochum)², M. Gotzmann (Bochum)³, B. Kovacs (Zürich)⁴, T. Dreher (Mannheim)⁵, C. Blockhaus (Krefeld)⁶, N. Klein (Leipzig)⁷, T. Kuntz (Leipzig)⁷, D.-I. Shin (Krefeld)⁶, H. Lapp (Bonn)⁸, S. L. Rosenkaimer (Heppenheim)⁹, M. Abumayyaleh (Mannheim)¹⁰, N. Hamdani (Bochum)¹¹, A. M. Saguner (Zürich)⁴, J. W. Erath-Honold (Frankfurt am Main)¹², F. Duru (Zürich)⁴, T. Beiert (Bonn)⁸, F. Schiedat (Gelsenkirchen)¹³, C. Weth (Saarbrücken)¹⁴, F. Custodis (Saarbrücken)¹⁴, I. Akin (Mannheim)¹⁰, A. Mügge (Bochum)¹⁵, A. Aweimer (Bochum)¹⁶, I. El-Battrawy (Bochum)^17
1Universitätsklinikum Münster Klinik für Kardiologie II - Rhythmologie Münster, Deutschland; ²Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil Medizinische Klinik II, Kardiologie und Angiologie Bochum, Deutschland; ³Kath. Klinikum Bochum Kardiologie und Rhytmologie Bochum, Deutschland; ⁴UniversitätsSpital Zürich Klinik für Kardiologie Zürich, Schweiz; ⁵Department of Cardiology, Angiology, Haemostaseology and Medical Intensive Care University Medical Center Mannheim, Medical Faculty Mannheim Mannheim, Deutschland; ⁶HELIOS Klinikum Krefeld Medizinische Klinik I Krefeld, Deutschland; ⁷Klinikum Sankt Georg Klinik für Kardiologie, Angiologie und intern. Intensivmedizin Leipzig, Deutschland; ⁸Universitätsklinikum Bonn Medizinische Klinik und Poliklinik II Bonn, Deutschland; ⁹Kreiskrankenhaus Bergstraße gGmbH Innere Medizin II Heppenheim, Deutschland; ¹⁰Universitätsklinikum Mannheim GmbH I. Medizinische Klinik Mannheim, Deutschland; ¹¹Kath. Klinikum Bochum Cellular Physiology Bochum, Deutschland; ¹²Universitätsklinikum Frankfurt Med. Klinik III - Kardiologie, Angiologie Frankfurt am Main, Deutschland; ¹³Marienhospital Gelsenkirchen GmbH Klinik für Kardiologie, Angiologie und Interne Intensivmedizin Gelsenkirchen, Deutschland; ¹⁴Klinikum Saarbrücken gGmbH Medizinische Klinik II Saarbrücken, Deutschland; ¹⁵Institut für Physiologie, Institut für Forschung und Lehre (IFL), Ruhr-Universität Bochum Abteilung für Zelluläre und Translationale Physiologie, Molekulare und Experimentelle Kardiologie Bochum, Deutschland; ¹⁶Berufsgenossenschaftlliches Universitätsklinikum Bergmannsheil gGmbH Medizinische Klinik II, Kardiologie und Angiologie Bochum, Deutschland; ¹⁷Klinikum der Ruhr-Universität Bochum Medizinische Klinik II, Kardiologie Bochum, Deutschland

Background: Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmia and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicentre WCD registry was to identify predictors of sustained ventricular arrhythmia in this population.

Methods and Results: In total, 1675 consecutive patients with WCD were included in a multicenter registry from 9 European centres, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained ventricular tachyarrhythmia (sustained ventricular tachycardia and ventricular fibrillation). Mean age of the WCD cohort was 59.3 years, and 79% of patients were male. Mean baseline left ventricular ejection fraction was 30% and increased to 42.6% at follow-up after 6-12 months. Sustained ventricular tachycardia was detected by WCD in 5.4% and ventricular fibrillation in 0.9% of all patients. Of the 507 patients (30.3%) receiving ICD-implantation during follow-up, sustained ventricular tachycardia was recorded in 47 patients (9.3%) and ventricular fibrillation in 13 patients (2.6%).
Non-ischemic cardiomyopathy (HR 0.6, 95% CI 0.4-0.9, p=0.011), left ventricular ejection fraction improvement in the first three months (HR 0.6, 95% CI 0.4-0.9, p=0.022), angiotensin-converting-enzyme-inhibitor use (HR 0.6, 95% CI 0.4-0.9, p=0.021) and aldosterone antagonist use (HR 0.7, 95% CI 0.5-1.0, p=0.034) were associated with a significantly lower risk of sustained ventricular tachyarrhythmia during follow-up. In contrast, atrial fibrillation and atrial flutter increased the risk (HR 1.9, 95% CI 1.0-3.4, p=0.031).

Conclusions: Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of sustained ventricular arrhythmias in the presence of non-ischemic cardiomyopathy and freedom from atrial fibrillation and atrial flutter. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for sustained ventricular tachyarrhythmia.

Table 1: Baseline characteristics of the cohort
Variables	n = 1675
Demographics
Male, n (%)	1326/1675 (79.2)
Age, mean±SD	59.3±14.8
Comorbidities
Coronary artery disease, n (%)	466/967 (48.2)
Myocardial infarction, n (%)	348/1078 (32.3)
Atrial fibrillation or atrial flutter, n (%)	391/1398 (28)
Drug treatment
ACE Inhibitors, n (%)	811/1157 (70.1)
Aldosterone antagonist, n (%)	754/1158 (65.1)
ß Blocker, n (%)	1440/1550 (92.9)
LVEF
LVEF at index, mean±SD	30±11.9
LVEF after 6-12 months, mean±SD	42.6±12.5
EF Improvement > 35%, n (%)	1009/1488 (67.8)
SD, Standard deviation; LVEF, left ventricular ejection fraction; ACE, Angiotensin-converting-enzyme

Table 2: Follow-up data
Variables	n = 1675
Recorded WCD Data
Wear days, mean±SD	65.1±45.9
Average wear hours, mean±SD	21.2±4.4
Arrhythmic episodes during WCD therapy
Sustained ventricular tachycardia, n (%)	90/1669 (5.4)
Ventricular fibrillation, n (%)	15/1667 (0.9)
WCD shocks
Appropriate, n (%)	44/1670 (2.6)
Inappropriate, n (%)	4/1670 (0.2)
CIED
Device implantation, n (%)	507/1612 (31.5)
Arrhythmic episodes post-CIED implantation
Sustained ventricular tachycardia, n (%)	47/359 (13.1)
Ventricular fibrillation, n (%)	13/359 (3.6)
CIED, cardiac implantable electronic device; WCD, wearable cardioverter defibrillator