清醒狗短暂缺血心肌复灌注时舒缩功能的变化

在狗的心脏上装入微超声探头和高精度微压力传感器,手术后两星期,在清醒状态下给予左冠状动脉旋支阻断三分钟。在复灌注过程中,观察到血液动力学指标与收缩期心室壁厚度(WT)迅速恢复正常;但在 dWT/dt—WT 环形图上出现舒张早期异常相,其形状与缺血过程不同。低氧和急遽冠状动脉过度充盈可以产生此种异常图形。我们推测,心肌缺血可能促使一些产物的形成,复灌注时它使冠脉过度舒张,冠脉灌注增加,从而造成舒张早期急遽充盈而形成了此种异常的形图。

CHANGES IN SYSTOLIC AND DIASTOLIC FUNCTION OF REPERFUSED MYOCARDIUM AFTER SHORT CORONARY OCCLUSIONS IN CONSCIOUS DOGS

Mongrel dogs were chronically implanted with sonomicrometer crystals anda high fidelity tip micromanometer to measure ventricular wall thickness(WT)and left ventricular pressure(LVP),respectively.Two weeks after surgical opera-tion,the left circumflex coronary artery was occluded with a hydraulic occluderfor 3 minutes in conscious condition.During reperfusion,the hemodynamicparameters and systolic wall thickening recovered to the normal level quickly,while an abnormal thickening phase during early relaxation(extra phase)appear-ed in the dWT/dt-WT loop(X-axis=WT,Y-axis=dWT/dt)with its pat-tern different from that during control and ischemic conditions.This kind ofpattern of the loop could be observed during hypoxia and during rapid overfillingof coronary artery.It is supposed that some substances,which may be producedin the ischemic myocardium,induced an extra dilation of coronary artery duringreperfusion and a rapid overperfusion in the early relaxation phase of thecardiac cycle,leading to the abnormal pattern in the loop.