Abstract 362: Multicenter, Retrospective Study of Ventricular Fibrillation Visualized by Echocardiogram With a Non-Shockable Elelctrocardiogram Following Out-of-Hospital Cardiac Arrest

Abstract

Introduction: Cardiac rhythm by ECG can be different from cardiac rhythm visualized by echocardiography (echo). Cardiac arrest interventions are largely based on the ECG rhythm and some patients with ventricular fibrillation (vfib) demonstrating a non-shockable ECG may not be rapidly defibrillated. Hypothesis: A significant percentage of out of hospital cardiac arrest (OHCA) with vfib are unrecognized by ECG. Goals - To measure the prevalence and survival outcomes for patients with a non-shockable ECG but vfib by echo. Methods: Analysis of echo images recorded during a previous multi-center, observational study of OHCA patients. ECG and echo during initial pause in CPR at arrival to the Emergency Department (ED) were reviewed. Echo imaging was reviewed for the presence of visible vfib blinded to all patient information. Image interpretation was performed by two experienced physicians with adjudication by a third. ECG interpretation was unblinded to patient information. Primary outcome was survival to hospital admission. Data is presented as mean (95%CI) Results - Vfib was unrecognized by ECG in 31% of patients in vfib at ED arrival (22 of 71). See Figure. Survival to hospital admission for patients with ECG vfib (18.2%, 95%CI 10.2-30.3) and echo vfib (18.2%, 95%CI 6.7-39.1) was similar. All 55 patients who presented in ECG vfib were defibrillated immediately, and 11 of 22 patients with a non-shockable ECG but echo vfib were defibrillated, but during a subsequent pause in CPR. Patients with ECG vfib had no echo before defibrillation. Patients with echo vfib demonstrated ECG PEA (n=9, 41%), asystole (n=7, 32%), or ECG vfib defibrillated to a non-shockable ECG with continued echo vfib that was not subsequently defibrillated (n=6, 11%). Conclusion: A significant percentage of OHCA vfib was not recognized at arrival to the ED, with 31% demonstrating a non-shockable ECG rhythm but vfib on echo. OHCA survival rate for echo vfib is similar to ECG vfib.