冠状动脉粥样硬化无疑是造成心肌梗塞的最重要的条件。但是心肌梗塞的发生还决定于许多附加的、有时还是决定性的致病因素:冠状血管痉攣,血栓形成的趋向增高,侧枝循环的状况,心肌功能过度紧张。在冠状血管有粥样硬化时,如果形成了很好的侧枝联系,就可以防止坏死性病变的发生。如果冠状血管变狭窄的过程进行得很缓慢,侧枝血管才来得及形成;如果变狭窄的过程进展迅速,由于侧枝吻合不良,就有发生心肌坏死的危险。目前对于冠状血管内血栓形成的原因和机制的看法已经有所改变。那种认为凝血因子含量增加对于血 Coronary atherosclerosis is undoubtedly the most important condition that causes myocardial infarction. However, the occurrence of myocardial infarction is also determined by a number of additional and sometimes decisive risk factors: coronary vasospasm, increased tendency for thrombosis, collateral circulation, and over-strained myocardial function. Coronary atherosclerosis, if the formation of a good collateral ties, can prevent the occurrence of necrotic lesions. If the process of coronary stenosis progresses very slowly, the collateral vessels have a chance of being formed; if the process of stenosis progresses rapidly, there is a risk of myocardial necrosis due to anastomosis of the lateral branches. The current view on the causes and mechanisms of coronary thrombosis has changed. That the increase in blood clotting factor for the blood