Abstract 233: Initial Arrest Rhythm and Outcome in Patients Undergoing Primary PCI for ST-Segment Elevation Myocardial Infarction Complicated by Out-of-Hospital Cardiac Arrest

Abstract

Background : The prognosis of patients with out of hospital cardiac arrest (OHCA) varies by the initial arrest rhythm. Patients with shockable rhythms such as ventricular tachycardia (VT) or ventricular fibrillation (VF) have better survival than those with nonshockable rhythms including asystole and pulseless electrical activity (PEA). The impact of initial arrest rhythm on outcome in ST-segment elevation myocardial infarction (STEMI) complicated by OHCA is unknown. Methods : The Los Angeles County Emergency Medical Services STEMI Receiving Center System coordinates and provides care for patients with STEMI and OHCA within a network of 33 primary PCI centers serving the 9.8 million residents of Los Angeles County. Between April and December 2011, a total of 61 patients with STEMI with OHCA and restoration of spontaneous circulation (ROSC) were treated with primary PCI. Patient characteristics and outcomes were analyzed based on initial arrest rhythm. Results: 61 patients with STEMI, OHCA and ROSC were treated with primary PCI during the study period. Over 80% of these patients had a door to balloon time of ≤ 90 minutes. 50 patients had a shockable initial arrest rhythm (VT, VF or AED analyzed/defibrillated) and 11 had a nonshockable rhythm (asystole, PEA). Initial neurologic status following ROSC was similar between groups but patients with initial asystole or PEA had worse neurologic status at discharge. The presence of a shockable initial rhythm was associated with a numerically superior rate of hospital survival but this did not reach statistical significance. Conclusions: Similar to the general cardiac arrest population, a shockable initial arrest rhythm is associated with better outcomes in patients with STEMI and OHCA. Analyses of patients with STEMI complicated by OHCA should be stratified by initial arrest rhythm as significant pathophysiologic differences may exist between these groups.