title: Impact of chronic cyanosis and reoxygenation on the microheterogeneity of the myocardial blood flow: digital radiographic study in neonatal rats.
abstract: OBJECTIVE
  This study sought to show the heterogeneity of myocardial blood flow in the chronically hypoxic infantile myocardium and its response to reoxygenation using a novel type of digital radiography.
  
  
  METHODS
  Newborn rats were housed in a hypoxic chamber or in a normal chamber (controls). After 4 or 8 weeks, the control rats were ventilated with normoxic conditions, and the rats housed under hypoxia were ventilated with either hypoxic (cyanotic group) or normoxic conditions (reoxygenation group). Desmethylimipramine labeled with tritium (HDMI) was injected into the left ventricle, and both ventricular free walls were sectioned and sliced from the subepicardium to the subendocardium at 10 mm thickness. The within-layer distribution of HDMI density was measured by digital radiography, and its spatial heterogeneity (i.e., flow heterogeneity) was quantified by the coefficient of variation (CV) of flows.
  
  
  RESULTS
  There were no differences in the CV between the groups in either ventricle at 4 weeks of age and no differences in the right ventricle at 8 weeks of age. There was a trend toward a higher left ventricular CV in the cyanotic group than in the control group at 8 weeks of age (0.637 ± 0.099 vs. 0.510 ± 0.060, P = 0.06). At 8 weeks of age, the CV was lower in both ventricles in the reoxygenation group than in those of the control and cyanotic groups.
  
  
  CONCLUSIONS
  The chronically hypoxic infantile myocardium exhibits regional flow heterogeneity similar to that observed in the normal myocardium in both ventricles and exhibits reduced flow heterogeneity in response to reoxygenation.
authors: Department of Cardiovascular Surgery, Okayama University Graduate School of Medicine and Dentistry, Japan.
authors: Tomoko
authors: T
authors: Tomii
authors: Osami
authors: O
authors: Honjo
authors: Takeshi
authors: T
authors: Matsumoto
authors: Hiroyuki
authors: H
authors: Tachibana
authors: Yasuhiro
authors: Y
authors: Fujii
authors: Kozo
authors: K
authors: Ishino
authors: Yasuo
authors: Y
authors: Ogasawara
authors: Shunji
authors: S
authors: Sano
mesh_terms: D000367:Age Factors; D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D002908:Chronic Disease; D003326:Coronary Circulation; D003490:Cyanosis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D003891:Desipramine; D004195:Disease Models, Animal; D006439:Hemodynamics; D008833:Microcirculation; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D010102:Oxygen Inhalation Therapy; D011856:Radiographic Image Enhancement; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003891:Desipramine