Persistent myocardial ischemia following chronic hyperoxia in conscious dogs.
Following acute occlusion of the proximal left anterior descending (LAD) coronary artery, dogs were exposed continuously for 4 days in an environmental chamber to either 21% or 40% oxygen. Regional transmural myocardial blood flow was then determined by means of radioactive microspheres (8 to 10 microD) while each animal breathed room air (approximately equal to 21% oxygen). Blood flows in the anterolateral and apical regions of the left ventricle in normoxic animals (n = 5) averaged 0.95 +/- 0.03 and 0.69 +/- 0.13 ml/min X gm-1, respectively. In hyperoxic dogs (n = 5), blood flows in these regions were significantly lower, averaging 0.71 +/- 0.07 and 0.28 +/- 0.08 ml/min X gm-1, respectively in the anterolateral free wall, the greatest disparity in perfusion between experimental groups occurred in the subendocardial layers, and macroscopic evidence of necrosis was more widespread after hyperoxia.
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000503:physiopathology; D001783:Blood Flow Velocity; D001835:Body Weight; D002908:Chronic Disease; D003326:Coronary Circulation; D003327:Coronary Disease / Q000139:chemically induced* / Q000150:complications / Q000503:physiopathology; D004285:Dogs; D008297:Male; D009203:Myocardial Infarction / Q000209:etiology / Q000503:physiopathology; D010100:Oxygen / Q000008:administration & dosage*; D010477:Perfusion
D010100:Oxygen