176-44: Evaluation of monitoring function of wearable cardioverter-defibrillator in patient at high risk of sudden cardiac death: A single-center Japanese experience

Abstract

Background: The Wearable cardioverter-defibrillator (WCD; Life Vest 4000, Zoll, PA, USA) plays a role not only as a cardioverter-defibrillator but as an arrhythmic event monitor and symptomatic event ECG recorder. Detection of non-sustained asymptomatic tachyarrhythmias, however, is not equipped algorithmically, and its usefulness remains unclear. Method: We studied 47 patients at high risk of ventricular tachyarrhythmias who were prescribed WCD (9 for out of hospital use; 35 for secondary prevention) from April 2014 to December 2015. We analyzed transmitted events via Lifevest network, which consisted of automatic detection and patient-initiated detection by holding the response button for .3 seconds. In the former 20 patients, a single tachycardia detection for tachycardia .200 beats/minute (bpm) was programmed, while in the latter 27, dual tachycardia detection (ventricular tachycardia (VT) for .130 and ventricular fibrillation (VF) for .200 bpm) was programmed. Results: During a median wearing duration of 16 (IQR 9-36) days, 548 events were transmitted. Of these, 501 were detected automatically and the other 80 by patient initiation. Most of the automatically detected transmissions (n = 484, 97%) were caused by noise detection, and most of patient-initiated ones (n = 72, 90%) were by frequent interruption of gong alarm for dislocated electrodes. Twenty-three (4.2%) true arrhythmic events were transmitted (sustained VT, 11; asystole, 4; non-sustained VT, 1; intermittent 2:1 atrioventricular block, 2; atrial fibrillation, 2; premature contractions, 3). There was no difference in the arrhythmia detection rate between the 2 detection program groups. Conclusion: Monitoring function of WCD is limited and seems to be insufficient in judging the necessity of implantable cardioverter-defibrillator by itself.