Deussen A, Flesche C W, Loncar R
Institut für Physiologie, Medizinische Fakultät Carl Gustav Carus, TU Dresden.
Anaesthesist. 1999 Jul;48(7):449-51. doi: 10.1007/s001010050729.
The myocardium of the left ventricle exhibits spatial heterogeneity of blood flow under physiological conditions. This study was designed to investigate, whether oxygen supply is jeopardized in low flow areas (blood flow < 50% of mean) under physiological conditions and whether areas of high flow (> 150% of mean) exhibit perfusion in excess of demand ("luxury perfusion").
The study was performed in anesthetized and ventilated beagle dogs. Local blood flow was reduced by mechanically narrowing of the r. circumflexus of the left coronary artery; myocardial blood flow was measured by the tracer-microsphere technique, free concentrations cellular adenosine by the SAH-technique, regional metabolism of substrates by the desoxyglucose-technique.
Low flow areas exhibited normal oxygenation of the myocardium, while in high flow areas no luxury perfusion could be demonstrated.
Myocardial blood flow and metabolism demonstrate significant spatial heterogeneity. There appears to be no absolute threshold of blood flow, where regional myocardial ischemia develops. Probably biochemical evidence of myocardial ischemia is determined by a local ratio of oxygen supply and demand.
在生理条件下，左心室心肌呈现血流的空间异质性。本研究旨在调查在生理条件下低血流区域（血流<平均血流的50%）的氧供应是否受到威胁，以及高血流区域（>平均血流的150%）是否存在灌注超过需求的情况（“奢侈灌注”）。
本研究在麻醉并通气的比格犬中进行。通过机械性狭窄左冠状动脉回旋支来降低局部血流；采用示踪微球技术测量心肌血流，采用SAH技术测量细胞内腺苷的游离浓度，采用脱氧葡萄糖技术测量底物的区域代谢。
低血流区域心肌氧合正常，而在高血流区域未发现奢侈灌注。
心肌血流和代谢表现出显著的空间异质性。似乎不存在区域心肌缺血发生时血流的绝对阈值。心肌缺血的生化证据可能由局部氧供需比决定。
