title: Coronary zero flow pressure and intramyocardial pressure in transiently arrested heart.
abstract: OBJECTIVE
  The aim of the study was to examine the relation between zero flow pressure and intramyocardial pressure in the inner and outer layers of the myocardium.
  
  
  METHODS
  Zero flow pressure was obtained in maximally vasodilated excised hearts by decreasing perfusion pressure (at 2 mm Hg.s-1) during transient heart arrest. Intramyocardial pressures in inner and outer myocardium were measured simultaneously with needle tip pressure transducers at depths of 8.0(SD 2.6) and 3.3(1.2) mm from the epicardium respectively. Ventricular and atrial pressure could be controlled at will.
  
  
  METHODS
  The excised hearts of eight mongrel dogs, body weight 14.0(0.8) kg, were used.
  
  
  RESULTS
  During left ventricular pressure elevation (0, 15, 30 mm Hg), zero flow pressures were 9.1(2.4), 13.8(2.2), and 19.1(5.1) mm Hg, respectively. Corresponding values of intramyocardial pressure at the outer myocardium were in good agreement with the zero flow pressures, at 9.1(3.4), 13.4(2.8), and 20.8(5.4) mm Hg. Values at the inner myocardium increased from 7.4(2.4) to 18.9(8.6) and 32.9(13.0) mm Hg. The latter two values were significantly higher than the corresponding values of zero flow pressure and intramyocardial pressure at the outer myocardium (p less than 0.05, p less than 0.01). In isotransmural pressure elevation, the three pressures increased almost equally.
  
  
  CONCLUSIONS
  The results show that zero flow pressure is strongly affected by intramyocardial tissue pressure, and if uneven intramyocardial pressure distribution is present the value of zero flow pressure depends on the lower values of intramyocardial pressure.
authors.affiliation: First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Satoh
authors.forename: Y
authors.initials: Y
authors.lastname: Maruyama
authors.forename: J
authors.initials: J
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Keitoku
authors.forename: K
authors.initials: K
authors.lastname: Hangai
authors.forename: T
authors.initials: T
authors.lastname: Takishima
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D004285:Dogs; D005260:Female; D006321:Heart / Q000502:physiology*; D006324:Heart Arrest, Induced; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium; D010477:Perfusion; D011312:Pressure