title: Subsequent ventricular fibrillation and survival in out-of-hospital cardiac arrests presenting with PEA or asystole.
abstract: BACKGROUND
  The prognostic implications of conversion to ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OHCA) patients with an initial non-shockable rhythm are unclear.
  
  
  OBJECTIVE
  Among OHCA patients with an initial non-shockable rhythm, survival is better in individuals who subsequently develop VF and are defibrillated.
  
  
  METHODS
  
  
  
  METHODS
  Utstein style population-based cohort study.
  
  
  METHODS
  adults (age>or=18 years) with OHCA of presumed cardiac etiology and initial rhythm of pulseless electrical activity (PEA) or asystole treated by emergency medical services systems in Osaka, Japan from January 1, 2001 to December 31, 2005. Primary outcome measure was one-month neurologically favorable survival (CPC<or=2). Outcome of patients with subsequent VF (SHOCK group) was compared to that of patients with sustained non-shockable rhythm (NON-SHOCK group) using logistic regression to adjust for potential confounding variables.
  
  
  RESULTS
  Of 14,316 OHCA, 12,353 cases had PEA or asystole as the initial rhythm. Of these, 11,766 (95%) remained in a non-shockable rhythm throughout the resuscitation effort while 587 (5%) subsequently developed VF and were defibrillated. Neurologically favorable survival at one month was significantly better in the SHOCK group (6% versus 1%, p<0.001). Subsequent VF remained a significant predictor (OR, 4.3; 95% CI, 2.8-6.7) of neurologically favorable survival after adjustment for potential confounders.
  
  
  CONCLUSIONS
  Based on a large-scaled population-based cohort of OHCA, subsequent VF with defibrillation was associated with better outcomes among patients with an initial non-shockable rhythm.
authors.affiliation: Department of Traumatology and Acute Critical Medicine, Osaka University, Graduate School of medicine, Suita, Japan. kajihanapu@yahoo.co.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kajino
authors.forename: Taku
authors.initials: T
authors.lastname: Iwami
authors.forename: Mohamud
authors.initials: M
authors.lastname: Daya
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nishiuchi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ikeuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimazu
authors.forename: Hisashi
authors.initials: H
authors.lastname: Sugimoto
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D004554:Electric Countershock / Q000379:methods*; D004632:Emergency Medical Services; D005260:Female; D006323:Heart Arrest / Q000150:complications* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D011379:Prognosis; D011446:Prospective Studies; D011674:Pulse; D015996:Survival Rate; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*