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目的观察和评价米力农联合肾上腺素对心肌顿押的治疗效果。方法杂种犬21条，制作局部心肌顿抑模型后，随机分成4组，分别给予生理盐水(I)、肾上腺素(Ⅱ)、米力农(Ⅲ)和米力农+肾上腺素(Ⅳ)治疗。分别于用药后5、10、30、60 min及停药30 min测定血流动力学和缺血区心肌氧供、氧耗变化。并于用药前和停药30 min切取左室心外膜下心肌组织作电镜检查。结果三治疗组用药后CO、冠脉流量(CBF)均显著增加，增加幅度依次为：Ⅳ＞Ⅲ＞Ⅱ，Ⅲ、Ⅳ两组SVR显著降低，Ⅱ组无明显变化。MERO2和MDO2／MVO2各治疗组均呈下降趋势。心肌超微结构：停药30 min I、Ⅱ两组，毛细血管仍淤血，间质水肿，并伴粒细胞浸润，但线粒体空泡较前明显减少；Ⅲ、Ⅳ两组停药30 min电镜下可见心肌细胞及间质水肿明显消退，毛细血管瘀血消失，偶见线粒体空泡。结论顿抑心肌对β受体激动剂反应性降低；正性肌力药物可促进顿抑心肌收缩功能的恢复，联合用药优于单独用药。“,”Objective To study the effects of differernt kinds of positive inotropics,epinephrine and milrinone,on myocardial stunning when given alone or in combination to experimental dogs. Methods 21 open chest anesthetized dogs that had been subjected to 15 min left anterior descending coronary artery occlusion and 30 min reperfusion to produce regional myocardial stunning were allocated into 4 groups :control group ( I ) ,epinephrine group (Ⅱ) ,milrinone group (Ⅲ) ,and milrinone＋epinephrine group (Ⅳ). The systemic hemodynamics, CBF,myocardial oxygen delivery and consumption of ischemic area were measured at 5,10, 30,60 min respectively after inotropics administration and 30 min after the drug was stopped. Results Epinephrine and milrinone given alone or in combination significantly increased cardiac output,stroke vol ume,myocardial oxygen delivery and left ventricular stroke work index,the order of incresing amplitude being as follows: Milrinone＋epinephrine＞Milrinone＞Epinephrine. In the combination group,CO,SV increased almost as much as the sum of both inotropics given separately. Systemic vascular resistance and pulmonary vascular resistance decreased in milrinone and milrinone＋epinephrine groups, but not in epinephrine group. MERO/MDO showed a tendency of decreasing after inotropics administration as compared with those in control group. Electronic microscopic examination showed that after inotropics treatment,the myocardial ultrastructure of ischemic area did not improve significantly in epinephrine group versus the control group,but in milrinone and milrinone＋epinephrine groups,the interstitial and intracellular edema reduced markedly,the capillary stasis vanished,and very few vacuoles could be seen in mitochondria. Conclusion The responsiveness of stunned myocardium to β agonists decreases, but milrinone,the phosphodiesterase inhibitor,may be the optimal agent for treatment of myocardial stunning. Inotropic simulation can restore regional work by restoring mechanical synchrony and improving energy efficiency,without greatly affecting regional MVO2. The effects of combined inotropics are better than the inotropics given separately in myocardial stunning. The results of our study might be helpful in clinical trial in treating myocardial stunning after ischemia reperfusion.