title: Conversion to shockable rhythms is associated with better outcomes in out-of-hospital cardiac arrest patients with initial asystole but not in those with pulseless electrical activity.
abstract: The prognostic implication of conversion from initially non-shockable to shockable rhythms in patients with out-of-hospital cardiac arrest (OHCA) remains unclear. Our objective is to determine whether the conversion to shockable rhythms is a reliable predictor of short- and long-term outcomes both in patients who initially presented with pulseless electrical activity (PEA) and in those with asystole.
  
  
  
  A secondary analysis was performed on non-traumatic OHCA cases ≥18 years old with PEA or asystole as initial rhythms, who were treated in the field and enrolled in the Resuscitation Outcomes Consortium (ROC) PRIMED study (clinicaltrials.gov/ct2/show/NCT00394706). We reported the characteristics and outcomes for those patients with or without shocks delivered in the field. Logistic regression analysis assessed the association of shock delivery with pre-hospital return of spontaneous circulation (ROSC), survival to hospital discharge and favorable neurological outcome as well.
  
  
  
  Of the 9902 included cases, 3415 (34.5%) were initially in PEA and 6487 (65.5%) were in asystole. 744 (21.8%) PEA and 1134 (17.5%) asystolic patients underwent rhythm conversions and received subsequent shocks. For asystolic patients, the adjusted odds ratios (ORs) of shock delivery for pre-hospital ROSC, survival to discharge and favorable neurological outcome were 1.862 (95%CI 1.590-2.180), 3.778 (95%CI 2.374-6.014) and 4.154 (95%CI 2.192-7.871) respectively, while for PEA patients they were 0.951 (95%CI 0.796-1.137), 1.115 (95%CI 0.720-1.726) and 1.373 (95%CI 0.790-2.385) respectively.
  
  
  
  Conversion to shockable rhythms was associated with better outcomes in initially asystolic OHCA patients, whereas such associations were not observed in patients initially in PEA.
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Ruiying
authors.initials: R
authors.lastname: Zheng
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Shengyuan
authors.initials: S
authors.lastname: Luo
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Jinli
authors.initials: J
authors.lastname: Liao
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Liu
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Xu
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhan
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China.
authors.forename: Xiaoxing
authors.initials: X
authors.lastname: Liao
authors.affiliation: The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510080, China; University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8579, USA. Electronic address: xiongyan@mail.sysu.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8579, USA.
authors.forename: Ahamed
authors.initials: A
authors.lastname: Idris
mesh_terms: D000328:Adult; D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D002681:China; D004554:Electric Countershock / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D055724:Electrophysiological Phenomena; D004632:Emergency Medical Services / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006323:Heart Arrest / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000175:diagnosis / Q000209:etiology; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality / Q000628:therapy*; D017063:Outcome Assessment, Health Care; D016019:Survival Analysis
keywords: Asystole; Cardiac arrest; Defibrillation; Outcomes; Pulseless electrical activity