Kawashima S, Yokoyama M, Sakamoto S, Okada T, Akita H, Mizutani T, Fukuzaki H
Jpn Heart J. 1982 Nov;23(6):951-60. doi: 10.1536/ihj.23.951.
This study was designed to determine how distal vasodilatory stimuli can alter coronary hemodynamics and the appearance of myocardial ischemia in the presence of severe coronary stenosis. In anesthetized open chest dogs, left circumflex coronary artery (LCx) flow, distal LCx perfusion pressure (DCPP), heart rate, and aortic pressure were monitored and regional myocardial ischemia was estimated from ST segment deviation in the epicardial and intramyocardial electrograms obtained from the electrodes located in the area supplied by LCx. In the presence of severe LCx constriction, intracoronary administration of adenosine (0.01 mg/Kg/min) and dipyridamole (0.05 mg/Kg) failed to augment LCx flow and induced further reduction in DCPP without changing systemic hemodynamics. In parallel with these hemodynamic changes, significant ST elevation was observed in the inner layer of the area supplied by the LCx. These results show that subepicardial vasodilation following vasodilatory stimuli can induce transmural flow redistribution and lead to subendocardial ischemia in the presence of severe coronary stenosis.
本研究旨在确定在严重冠状动脉狭窄情况下，远端血管舒张刺激如何改变冠状动脉血流动力学以及心肌缺血的表现。在麻醉开胸犬中，监测左旋冠状动脉（LCx）血流、LCx远端灌注压（DCPP）、心率和主动脉压，并根据位于LCx供血区域的电极所记录的体表心电图和心内膜下心电图的ST段偏移来评估局部心肌缺血。在严重LCx狭窄的情况下，冠状动脉内注射腺苷（0.01 mg/Kg/分钟）和双嘧达莫（0.05 mg/Kg）未能增加LCx血流，且在不改变全身血流动力学的情况下导致DCPP进一步降低。与这些血流动力学变化同时，在LCx供血区域的内层观察到显著的ST段抬高。这些结果表明，在严重冠状动脉狭窄情况下，血管舒张刺激后心外膜下血管舒张可导致跨壁血流重新分布并引起心内膜下缺血。
