局部心肌顿抑对全身血流动力学及心肌氧供需平衡的影响

Effects of Regional Myocardial Stunning on Systemic Hemodynamics and Myocardial Oxygen Balance in Experimental Dogs

目的 观察局部心肌顿抑对全身血流动力学及心肌氧供需平衡的影响。方法 杂种犬 33条 ,常温下 L AD阻断 1 5 min,观察再灌注后全身血流动力学、冠脉流量及缺血心肌氧供需平衡的变化。结果 MAP在冠脉阻断期间稍下降 ,再灌注后升至基础水平 ;HR在缺血 /再灌注过程中均明显增快 ;冠脉阻断后 ,CO、SV、L VSWI均迅疾下降 ,再灌注 5 min略有升高 ,之后进行性下降 ;再灌注后 SVR及 PVR均呈进行性增高 ;再灌注 5 min冠脉流量、MDO2 和MVO2 均显著升高 ,然后同步下降 ;MERO2 在缺血 /再灌注过程中无明显变化。电镜检查 :再灌注 30 min,心肌纤维肿胀 ,间质明显水肿 ,毛细血管淤血 ,线粒体大量空泡。结论 局部心肌顿抑可引起明显的血流动力学变化 ;再灌注初期存在明显的氧耗反常 ,而再灌注后期心肌氧供。

Objective To investigate the effects of regional myocardial stunning on systemic hemodynamics and myocardial oxygen balance.Methods In 33 open chest anesthetized dogs subjecting to 15 min left anterior descending (LAD) coronary artery occlusion under normal temperature,the systemic hemodynamics,coronary blood flow (CBF),myocardial oxygen delivery and consumption were determined after reperfusion.Results MAP decreased slightly during LAD occlusion, but returned to baseline after reperfusion.After LAD was occluded,CO,SV and LVSWI reduced rapidly and significantly,and increased a little 5 min after reperfusion,then a more severe reduction was seen,accompanied with a proceeding increasing of AVR and PVR.At the early stage of reperfusion (5 min.),CBF,MDO 2 and MVO 2 increased significantly,then decreased in parallel rapidly,after 10 min.of reperfusion,all the parameters were lower than the basic value.Myocardial oxygen extraction rate (MERO 2) did not change markedly during LAD occlusion/reperfusion period.Histological changes of ischemic area at 30 min after reperfusion showed interstitial and intracellular edema,mitochondrial vacuolization,and capillary stasis under electronic microscopy.Conclusion Regional myocardial stunning may result in signigicant change of systemic hemodynamics.At the early stage of reperfusion,there is an apparent “O 2 consumption paradox”, but CBF matches MVO 2 10 min after reperfusion according to this study.