title: A method for detecting chaos in canine myocardial microcirculatory red cell flux.
abstract: OBJECTIVE
  To determine whether red cell movement, as measured by laser Doppler velocimetry, in the capillary net of the beating heart is chaotic.
  
  
  METHODS
  Using two dog hearts, in situ red blood cell flux was measured at many sites. Simultaneously, epicardial arterial flow and left ventricular pressure were recorded via transit-time flowmeter and catheter manometer, respectively. The presence or absence of chaos was tested by two methods: Lyapunov exponents and correlation dimension.
  
  
  RESULTS
  For capillary red cell flux, the Lyapunov was strongly positive at most sites. It was less so for coronary arterial flow and least for left ventricular pressure. Correlation dimension calculation was less able to distinguish the presence or absence of chaos in capillary red cell tissue flux, coronary arterial flow, and left ventricular pressure.
  
  
  CONCLUSIONS
  Capillary red cell flux (movement of red cells in capillaries) is nonlinear, (i.e., chaotic). This complexity suggests that the primary control for oxygen delivery to cardiac myocytes by red blood cells resides in the microcirculation. Also, capillary red cell flux is bifractal, suggesting an ordering of control.
authors.affiliation: School of Health and Human Performance, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: K D
authors.initials: KD
authors.lastname: Barclay
authors.forename: G A
authors.initials: GA
authors.lastname: Klassen
authors.forename: C
authors.initials: C
authors.lastname: Young
mesh_terms: D000818:Animals; D001794:Blood Pressure; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000166:cytology / Q000502:physiology; D004285:Dogs; D004912:Erythrocytes / Q000502:physiology*; D017709:Fractals; D006352:Heart Ventricles / Q000166:cytology; D017078:Laser-Doppler Flowmetry; D008833:Microcirculation / Q000166:cytology* / Q000502:physiology*; D017711:Nonlinear Dynamics; D013223:Statistics as Topic; D016276:Ventricular Function