Suga H
Am J Physiol. 1979 Mar;236(3):H494-7. doi: 10.1152/ajpheart.1979.236.3.H494.
The possibility has been proposed earlier that the specific pressure-volume (P-V) area bounded by the left ventricular end-systolic and end-diastolic P-V curves and the isovolumic relaxation part of the P-V loop represents mechanical potential energy that has been built during systole and is stored at end systole in the wall of the ventricle. In the present study on canine left ventricles, as much as 70% of the P-V area was actually converted into external mechanical work when ventricular volume was allowed to decrease at an appropriate speed (about 55 ml/s in 70 g left ventricle) during relaxation. Less external work was extracted from the same P-V area when the speed of volume reduction was either higher or lower than that speed. These results indicate that the P-V area is equivalent to a form of potential energy, which is wasted with isovolumic relaxation but most of which is convertible to external mechanical work if the ventricle is allowed to eject against an appropriately decreasing afterload during relaxation.
早些时候有人提出一种可能性，即由左心室收缩末期和舒张末期压力-容积（P-V）曲线以及P-V环的等容舒张部分所界定的特定压力-容积（P-V）面积代表了在收缩期建立并在收缩末期存储于心室壁中的机械能。在目前对犬左心室的研究中，当在舒张期心室容积以适当速度（70g左心室中约为55ml/s）减小时，高达70%的P-V面积实际上转化为了外部机械功。当容积减小速度高于或低于该速度时，从相同P-V面积中提取的外部功较少。这些结果表明，P-V面积相当于一种势能形式，其在等容舒张期会被浪费，但如果在舒张期允许心室在适当降低的后负荷下射血，其中大部分可转化为外部机械功。
