Abstract 16751: Life-Threatening Arrhythmias During Wearable Cardioverter Defibrillator Use
Background: Recent emergency medicine studies have suggested that asystoles are increasing as the presenting arrhythmia of sudden cardiac arrest (SCA), with a proportional reduction in shockable ventricular arrhythmias (VT/VF). This is an important trend since successful resuscitation approaches are directly related to the presenting rhythm. The current wearable cardioverter defibrillator (WCD) is designed to record and alarm for both sustained VT/VF and asystole, providing a treatment shock for VT/VF and voice alerts to “Call for help. Perform CPR” for asystole. The objective of this study was to determine whether there has been a change in the proportion of VT/VF versus asystole as the initial presenting arrhythmia over the past 8 years of commercial WCD use.
Methods: All asystole or treated VT/VF events that were recorded by the WCD (LifeVest®, ZOLL) from 2006-2013 were retrospectively analyzed. An event was defined as all arrhythmias occurring within a 24 hour period. Events were classified as asystole if the initial presenting rhythm was asystole (with at least a 5 second pause) and as VT/VF if the initial presenting rhythm was sustained VT/VF.
Results: Over eight years, 2184 patients (pts) (74% male, age 64 ± 13 years) had 1686 treated VT/VF events and 702 asystole events. Pts who had an asystole event were older than those who had a VT/VF event (67 ± 11 versus 63 ± 13, respectively)(p<0.05). There was no difference in sex between the two groups. The yearly percentage of asystoles varied from 23-32%, a difference that is not significant (p=0.48).
Conclusions: The WCD provides a unique opportunity to record ECG rhythms at the onset of a potential SCA and prior to defibrillation. This study suggests that the majority of arrhythmias initially present as VT/VF, which is amenable to defibrillation therapy, and the rate of asystoles as the presenting rhythm has not significantly changed over the past eight years of WCD use.
Author Disclosures: N.R. Bianco: Employment; Significant; ZOLL. J. Sun: Employment; Significant; ZOLL. S.J. Szymkiewicz: Employment; Significant; ZOLL.
- © 2014 by American Heart Association, Inc.