Szekeres L, Csík V, Udvary E
Acta Med Acad Sci Hung. 1975;32(3-4):349-56.
Haemodynamic, metabolic and ECG alterations due to a "critical" stenosis of the left anterior descending coronary artery (LAD) with and without additional work load induced by pacing and the changes due to a total obstruction of the artery have been investigated in anaesthetized open-thorax dogs. Direct ECG recording was done from the epicardial surface of the area perfused by the constricted coronary artery; blood samples were collected from the same area for estimation of metabolites. It was shown that ischaemic biochemical changes (decrease of myocardial lactate uptake and of the ratio myocardial O2 supply/myocardial O2 demand) can be detected along with a reduction of flow in the constricted artery long before the appearance of ischaemic ST-segment elevation in the epicardial ECG. This change can be evoked by an additional work load induced by pacing but even at the stage of manifest ischaemia, left ventricular end-diastolic pressure (LVEDP) is unaffected. It increases only after complete obstruction of the LAD. Accordingly, ischaemic metabolic changes in the area with restricted blood supply seem to be the most sensitive indicator of an incipient coronary insufficiency. ECG and particularly LVEDP changes are limited value, since they only appear if the ischaemic damage and/or the ischaemic area is sufficiently large.
在麻醉开胸犬身上，研究了左前降支冠状动脉（LAD）“临界”狭窄时，有无起搏诱导的额外负荷情况下的血流动力学、代谢和心电图改变，以及该动脉完全阻塞后的变化。通过被狭窄冠状动脉灌注区域的心外膜表面直接记录心电图；从同一区域采集血样以评估代谢产物。结果表明，在心外膜心电图出现缺血性ST段抬高之前很久，随着狭窄动脉血流减少，即可检测到缺血性生化改变（心肌乳酸摄取减少以及心肌氧供应/心肌氧需求比值降低）。这种改变可由起搏诱导的额外负荷引发，但即使在明显缺血阶段，左心室舒张末期压力（LVEDP）也未受影响。只有在LAD完全阻塞后它才会升高。因此，血液供应受限区域的缺血性代谢改变似乎是早期冠状动脉供血不足最敏感的指标。心电图尤其是LVEDP改变的价值有限，因为它们只有在缺血损伤和/或缺血区域足够大时才会出现。
