title: Median frequencies of prolonged ventricular fibrillation treated by V-A ECMO correspond to a return of spontaneous circulation rate.
abstract: BACKGROUND
  The aim of our study was to analyze, in a pig model of prolonged ventricular fibrillation (VF) treated by veno-arterial extracorporeal membrane oxygenation (ECMO), the time dependent changes of VF wavelet frequency obtained from intracardial signals and its relations to return of spontaneous circulation (ROSC).
  
  
  METHODS
  11 female pigs (50.3 ± 3.4 kg) under general anesthesia had undergone 15 min of VF with ECMO flow of 5 to 10 ml/kg per min simulating "untreated" VF followed by continued VF with full ECMO flow of 100 ml/kg per min. The median frequency (MF) of VF from right ventricular apex, coronary perfusion pressure, myocardial oxygen metabolism and resuscitability were determined.
  
  
  RESULTS
  Median (interquartile range) of MF of fibrillatory wavelets in minute 15 of low ECMO flow [9.7 Hz (8.3; 10.1)] was not significantly changed in comparison to minute 1 [10.5 Hz (9.8; 12.4)], p = 0.12. Five minutes after full ECMO initiation MF increased [11.6 Hz (10.6; 13.5)], p = 0.04 (compared to minute 15 of VF) and did not deteriorate during the rest of ECMO treatment. Out of all subjects, three animals did not reach ROSC. Those subjects demonstrated deeper decrease of MF at the VF minute 15 as compared to others [-2.4 Hz (-2.5; -2.3) vs. -0.6 Hz (-1.6; -0.1)] and continuously significantly higher increase in MF on full ECMO support [4.3 Hz (2.9; 5.6) vs. 1.1 Hz (0.6; 1.6)] with p = 0.05 for both observations, respectively.
  
  
  CONCLUSIONS
  The veno-arterial ECMO reperfusion influences MF of VF wavelet obtained from right ventricular apex. The course of changes in wavelet frequency corresponds to a presence of later ROSC.
authors.affiliation: 1 Second Department of Medicine - Department of Cardiovascular Medicine, First Faculty of Medicine, Charles University, Prague - Czech Republic.
authors.forename: Stepan
authors.initials: S
authors.lastname: Havranek
authors.forename: Jan
authors.initials: J
authors.lastname: Belohlavek
authors.forename: Mikulas
authors.initials: M
authors.lastname: Mlcek
authors.forename: Michal
authors.initials: M
authors.lastname: Huptych
authors.forename: Tomas
authors.initials: T
authors.lastname: Boucek
authors.forename: Tomas
authors.initials: T
authors.lastname: Svoboda
authors.forename: Jaromir
authors.initials: J
authors.lastname: Fichtl
authors.forename: Matej
authors.initials: M
authors.lastname: Hrachovina
authors.forename: Ales
authors.initials: A
authors.lastname: Linhart
authors.forename: Otomar
authors.initials: O
authors.lastname: Kittnar
mesh_terms: D000818:Animals; D062186:Arterial Pressure / Q000502:physiology; D016887:Cardiopulmonary Resuscitation / Q000379:methods; D004195:Disease Models, Animal; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D005260:Female; D020127:Recovery of Function / Q000502:physiology; D013552:Swine; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000628:therapy*