Utility of wearable cardioverter defibrillators in European patients early after myocardial infarction

Background: Post-myocardial infarction (MI) and post-revascularization patients (pts) with low ejection fractions (EF) can be protected from death due to sudden cardiac arrest (SCA) immediately post-discharge with a wearable cardioverter defibrillator (WCD) until decisions on long-term risk management can reasonably be formulated. This study examines the utility of providing a WCD to European pts identified by their caregivers to be at high risk for SCA during these waiting periods. Methods: The European WCD medical order database was searched for pts who were coded as "recent MI with EF≤35%" or "recent revascularization with EF≤35%", then matched to device-recorded data. Only pts who completed or ended use, and wore the WCD for ≥15 minutes were used for this analysis. SCA was defined as all sustained ventricular tachycardia/fibrillation (VT/VF) or asystole occurring within 24 hours of the index arrhythmia. WCD resuscitation was defined as regaining consciousness after treatment for SCA. Results: Between 2/2010 and 12/2012, 576 unique pts matched study criteria. Pts (age 60±12 years, 85% male) wore the WCD for a median of 51 days. The WCD appropriately treated 13 pts for VT/VF. No asystole events occurred during use. Resuscitation success was 100%. The median time to SCA was 15 days after initiating WCD use. ![Figure][1] Figure 1. Timing of SCA events Conclusions: SCA occurred in 2.3% of pts having a compromised EF after MI and/or revascularization, and the majority of SCA occurred during the first month of use. The WCD resuscitated 100% of pts that experienced SCA. [1]: pending:yes