title: Ventricular Fibrillation Waveform Changes during Controlled Coronary Perfusion Using Extracorporeal Circulation in a Swine Model.
abstract: BACKGROUND
  Several characteristics of the ventricular fibrillation (VF) waveform have been found predictive of successful defibrillation and hypothesized to reflect the myocardial energy state. In an open-chest swine model of VF, we modeled "average CPR" using extracorporeal circulation (ECC) and assessed the time course of coronary blood flow, myocardial metabolism, and myocardial structure in relation to the amplitude spectral area (AMSA) of the VF waveform without artifacts related to chest compression.
  
  
  METHODS
  VF was induced and left untreated for 8 minutes in 16 swine. ECC was then started adjusting its flow to maintain a coronary perfusion pressure of 10 mmHg for 10 minutes. AMSA was calculated in the frequency domain and analyzed continuously with a 2.1 s timeframe and a Tukey window that moved ahead every 0.5 s.
  
  
  RESULTS
  AMSA progressively declined during untreated VF. With ECC, AMSA increased from 7.0 ± 1.9 mV·Hz (at minute 8) to 12.8 ± 3.3 mV·Hz (at minute 14) (p < 0.05) without subsequent increase and showing a modest correlation with coronary blood flow of borderline statistical significance (r = 0.489, p = 0.0547). Myocardial energy measurements showed marked reduction in phosphocreatine and moderate reduction in ATP with increases in ADP, AMP, and adenosine along with myocardial lactate, all indicative of ischemia. Yet, ischemia did not resolve during ECC despite a coronary blood flow of ~ 30% of baseline.
  
  
  CONCLUSIONS
  AMSA increased upon return of coronary blood flow during ECC. However, the maximal level was reached after ~ 6 minutes without further change. The significance of the findings for determining the optimal timing for delivering an electrical shock during resuscitation from VF remains to be further explored.
authors.affiliation: Resuscitation Institute at Rosalind Franklin University or Medicine and Science, North Chicago, Illinois, United States of America.|Section of Critical Care Medicine at the CAPT James A. Lovell Federal Health Care Center, North Chicago, Illinois, United States of America.
authors.forename: Raúl J
authors.identifier: http://orcid.org/0000-0002-3848-7227
authors.initials: RJ
authors.lastname: Gazmuri
authors.affiliation: ZOLL Medical Corporation, Chelmsford, Massachusetts, United States of America.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Kaufman
authors.affiliation: Resuscitation Institute at Rosalind Franklin University or Medicine and Science, North Chicago, Illinois, United States of America.
authors.forename: Alvin
authors.initials: A
authors.lastname: Baetiong
authors.affiliation: Resuscitation Institute at Rosalind Franklin University or Medicine and Science, North Chicago, Illinois, United States of America.
authors.forename: Jeejabai
authors.initials: J
authors.lastname: Radhakrishnan
mesh_terms: D000818:Animals; D016887:Cardiopulmonary Resuscitation; D003326:Coronary Circulation / Q000502:physiology*; D005112:Extracorporeal Circulation; D006439:Hemodynamics / Q000502:physiology; D008297:Male; D009206:Myocardium / Q000378:metabolism; D013552:Swine; D014693:Ventricular Fibrillation / Q000503:physiopathology*