急性心肌梗塞时心肌单相动作电位变化的实验研究

本文通过结扎12支家兔左冠状动脉前降支造成实验性心肌梗塞模型,使用接触电极引导心外膜单相动作电位和同步记录体表心电图,并以微机实时分析。结扎冠脉后,缺血区很快出现MAPA减小,Vmax降低,负相波出现,平台期后段抬高,MAPD不同程度延长。非缺血区MAT则无此改变。实验发现,MAP的改变早于心电图的改变;MAP变化程度受缺血程度的影响,病理切片示不同组织学改变,上述结果表明MAP是判断早期缺血的敏感而直接的指标。

EXPERIMENTAL STUDY OF CHANGES OF MYOCARDIAL MONOPHASIC ACTION POTENTIAL DURING ACUTE MYOCARDIAL INFARCTION

Experimental model of myocardial infarction was established by ligating the left anterior descending coronary arteries of 12 rabbits. Then the contact electrode was used to record the monophasic action potential(MAP)on the epicardium, the electrocardiogram(ECG)was recorded synchronously; and real-time analysis with a microcomputer was made. As soon as those arteries were occluded, there appeared in the infarction zone a significant diminution of the monophasic action potential amplitude and the maximal depolarization rate of phase 0, followed by a negative wave and elevation of the plateau phase, but the monophasic action potential duration(MAPD) was prolonged to various degrees. They remained unchanged in the non-infarction area. It was also discovered that the changes in MAP were prior to those on ECG, and were affected by the severity of ischemia. Pathological slices showed various histologic changes. These results showed that MAP was a sensitive direct index for the detection of early ischemia.