title: Real-time electrogram analysis for monitoring coronary blood flow during human ventricular fibrillation: implications for CPR.
abstract: BACKGROUND
  Effective chest compressions during prolonged ventricular fibrillation (VF) have been shown to increase the chances of successful defibrillation to a rhythm associated with a sustainable cardiac output. There is currently no effective method of recording the degree of antegrade coronary artery flow during chest compression in VF.
  
  
  OBJECTIVE
  This study sought to quantify the relationship between the antegrade coronary flow and the characteristics of human VF using near real-time wavelet-based electrocardiographic markers.
  
  
  METHODS
  VF experiments were conducted in 8 isolated human hearts. The Langendorff perfusion enabled different flow rates (perfusion) during VF, which allowed for the simulation of chest compression with different efficacies. After the initiation of VF, the hearts were maintained in ischemia (no flow) for 3 minutes, followed by a 2-minute reperfusion and defibrillation. The experiments were repeated at flows of 0%, 30%, and 100% of baseline perfusion, and volume-conducted surface electrograms were recorded and analyzed using continuous wavelet transform in 5-second frames.
  
  
  RESULTS
  Near real-time wavelet features were derived that demonstrated significant differences in the multicomponent nature of VF signals and predicted perfusion rate characteristics for different flow rates (i.e., 0%, 30%, and 100%; P < .0006). A pattern classifier was trained using the feature values from 5 hearts, and the flow rates for 3 additional hearts were predicted with an accuracy of 90%.
  
  
  CONCLUSIONS
  VF electrogram characteristics as measured by wavelet analysis relate to antegrade coronary flow rate during VF. These findings suggest that chest compression efficacy of physiological importance could be monitored using near real-time wavelet analysis.
authors.affiliation: Ryerson University, Toronto, Ontario, Canada.
authors.forename: Karthikeyan
authors.initials: K
authors.lastname: Umapathy
authors.forename: Farbod H
authors.initials: FH
authors.lastname: Foomany
authors.forename: Paul
authors.initials: P
authors.lastname: Dorian
authors.forename: Talha
authors.initials: T
authors.lastname: Farid
authors.forename: Gopal
authors.initials: G
authors.lastname: Sivagangabalan
authors.forename: Krishnakumar
authors.initials: K
authors.lastname: Nair
authors.forename: Stephane
authors.initials: S
authors.lastname: Masse
authors.forename: Sridhar
authors.initials: S
authors.lastname: Krishnan
authors.forename: Kumaraswamy
authors.initials: K
authors.lastname: Nanthakumar
mesh_terms: D016887:Cardiopulmonary Resuscitation; D003326:Coronary Circulation; D004562:Electrocardiography; D006801:Humans; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*