Abstract 186: Baseline ECG Predictors of 90-Day Survival in Wearable Cardioverter-Defibrillator Patients Experiencing a Sudden Cardiac Arrest
Purpose: Factors affecting survival after SCA resuscitation continues to be an active area of investigation. The current wearable cardioverter defibrillator (WCD) records ECG periodically. The objective of this study was to determine whether there are any basic ECG differences in patients (pts) that died <90d after first shock versus those that were alive 90d post-shock. We analyzed ECGs at baseline (Base), one week prior to SCA (1WK), and immediately prior to first shock for ventricular tachyarrhythmias VT/VF (pre-S).
Methods: 100 sequential WCD pts (68% male, age 59 ± 16 years) shocked for VT/VF between November 2009 and June 2011 were retrospectively analyzed. Heart rate, QRS duration, QRS amplitude, corrected QT duration (QTc), ectopic activity and rhythm were manually measured at Base, 1WK, and pre-S. The WCD has four non-adhesive ECG electrodes, and measurements were made on both the side-to-side (ss) and front-to-back (fb) leads. Only pts wearing the WCD ≥1 week were included for analysis.
Results: 77 pts survived ≥90 days post shock (68% male, age 58 ± 16 years), and 23 pts died <90 days after first shock (70% male, age 63 ± 13 years). Those pts that died <90 days after first shock had a longer QTc and a shorter QRS amplitude at Base than those surviving ≥90 days post-shock (Table 1)(p≤0.05).
Conclusions: The WCD provides an opportunity to monitor ECG rhythms in at-risk pts prior to defibrillation. Similar to studies of overall mortality, this small study suggests that QT duration and QRS amplitude may be important predictive markers of survival post-SCA.
- © 2012 by American Heart Association, Inc.