title: The ventricular fibrillation waveform approach to direct postshock chest compressions in a swine model of VF arrest.
abstract: BACKGROUND
  In retrospective swine and human investigations of ventricular fibrillation (VF) cardiac arrest, the amplitude-spectral area (AMSA), determined from the VF waveform, can predict defibrillation and a return of spontaneous circulation (ROSC).
  
  
  OBJECTIVE
  We hypothesized that an algorithm using AMSA in real time to direct postshock chest compression (CC) duration would shorten the time to ROSC and improve neurological outcome in a swine model of VF cardiac arrest with acute myocardial infarction (AMI) or nonischemic myocardium.
  
  
  METHODS
  AMI was induced by occlusion of the left anterior descending artery. VF was untreated for 10 min. Animals were randomized to either traditional resuscitation with 2 min of CC after each shock or to an AMSA-guided algorithm where postshock CCs were shortened to 1 min if the preshock AMSA exceeded 20 mV-Hz.
  
  
  RESULTS
  A total of 48 animals were studied, 12 in each group (AMI vs. normal, and traditional vs. AMSA-guided). There was a nonsignificant shorter time to ROSC with an AMSA-guided approach in AMI swine (17.2 ± 3.4 vs. 18.5 ± 4.7 min, p = NS), and in normal swine (13.5 ± 1.1 vs. 14.4 ± 1.2, p = NS). Neurological outcome was similar between traditional and AMSA-guided animals. AMSA predicted ROSC (p < 0.001), and a threshold of 20 mV-Hz gave a sensitivity of 89%, with specificity of 29%.
  
  
  CONCLUSIONS
  Although AMSA predicts ROSC in a swine model of VF arrest in both AMI and normal swine, a waveform-guided approach that uses AMSA to direct postshock CC duration does not significantly shorten the time to ROSC or alter neurological outcome.
authors.affiliation: The Sarver Heart Center at the University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Meghan
authors.initials: M
authors.lastname: McGovern
authors.affiliation: The Sarver Heart Center at the University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Daniel
authors.initials: D
authors.lastname: Allen
authors.affiliation: The Sarver Heart Center at the University of Arizona College of Medicine, Tucson, Arizona; West Virginia University Heart Institute, Morgantown, West Virginia.
authors.forename: Fahd
authors.initials: F
authors.lastname: Chaudhry
authors.affiliation: The Sarver Heart Center at the University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Zacherie
authors.initials: Z
authors.lastname: Conover
authors.affiliation: The Sarver Heart Center at the University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Ronald
authors.initials: R
authors.lastname: Hilwig
authors.affiliation: The Sarver Heart Center at the University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Julia H
authors.initials: JH
authors.lastname: Indik
mesh_terms: D000465:Algorithms; D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006323:Heart Arrest / Q000209:etiology / Q000628:therapy*; D006336:Heart Massage; D008297:Male; D023421:Models, Animal; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology*; D011237:Predictive Value of Tests; D013552:Swine; D013997:Time Factors; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology*
keywords: cardiopulmonary resuscitation; defibrillation; heart arrest; myocardial infarction; ventricular fibrillation