Meyer T E, Föex P, Ryder W A
Department of Medicine, University of Massachusetts Medical Center, Worcester 01655.
Coron Artery Dis. 1994 Jun;5(6):471-9.
Limited information is available about the earliest manifestations of ischemia in an area of myocardium supplied by a critically constricted vessel following abrupt occlusion of another vessel. The aim of this study was to describe quantitatively the mechanical behavior of different non-ischemic zones, with and without critical stenosis of the supplying artery.
Regional myocardial function was measured in 14 open-chest anesthetized dogs, with piezoelectric length and thickness crystals placed within the perfusion beds of the proximal left anterior descending and left circumflex arteries. After baseline recordings, the left circumflex artery was critically constricted and the left anterior descending artery was abruptly occluded for 60 s. The same procedure was repeated after 30 min without stenosis of the artery. After 45 min of recovery, the same protocol was repeated for a narrowed left anterior descending artery.
Regional performance was assessed by analyzing the phases of segmental contraction. In the non-ischemic zone, isovolumic shortening and thickening and systolic shortening increased following left anterior descending artery occlusion, whereas, in the presence of critical constriction of the circumflex artery, isovolumic and systolic shortening and thickening did not increase. Occlusion of the left circumflex artery resulted in a significant increase in isovolumic shortening and thickening, ejection shortening, systolic shortening and thickening, whereas, with critical constriction of the left anterior descending artery, the same segment did not exhibit hyperkinesis.
The compensatory potential of the non-ischemic zone seems to be dependent on whether there is restriction to its vascular supply.
关于在另一血管突然闭塞后，由严重狭窄的血管供应的心肌区域缺血的最早表现，目前可用信息有限。本研究的目的是定量描述不同非缺血区域在供应动脉有无严重狭窄情况下的力学行为。
在14只开胸麻醉的犬中测量局部心肌功能，将压电长度和厚度晶体置于左前降支近端和左旋支动脉的灌注床内。在记录基线后，将左旋支动脉严重狭窄，然后将左前降支动脉突然闭塞60秒。在动脉无狭窄的情况下30分钟后重复相同程序。恢复45分钟后，对狭窄的左前降支动脉重复相同方案。
通过分析节段性收缩的各阶段来评估局部性能。在非缺血区域，左前降支动脉闭塞后等容缩短、增厚和收缩期缩短增加，而在左旋支动脉存在严重狭窄时，等容和收缩期缩短及增厚并未增加。左旋支动脉闭塞导致等容缩短、增厚、射血缩短、收缩期缩短和增厚显著增加，而在左前降支动脉严重狭窄时，同一节段未表现出运动亢进。
非缺血区域的代偿潜力似乎取决于其血管供应是否受到限制。
