Kane R L, McMahon T A, Wagner R L, Abelmann W H
Circ Res. 1976 Feb;38(2):74-80. doi: 10.1161/01.res.38.2.74.
Analysis of passive right and left ventricular pressure-volume curves for hearts of 72 Syrian golden hamsters studied in vitro showed increases in ventricular weight, volume, and compliance at mid-age. Both ventricles were filled by syringe pumps at a constant rate. Ventricular compliance (dV/dP) was determined by electronic differentiation of the intraventricular pressures and formation of the ratio (dV/dt)/(dP/dt) as a continuous function of intraventricular pressure between 0 and 30 mm Hg. By relating, with justification, the left ventricle to a thin-walled elastic sphere, ventricular elastic moduli, E, for different ages were compared at constant levels of myocardial wall stress, sigma. The elastic modulus E proved to be a linear function of sigma. The slope of the E-sigma plot yielded a stiffness constant, K, for each age group. Body weight, heart weight, end-diastolic volume, and dV/dP all varied by more than 200% up and then down as a function of age, but K was not a significant function of age. These results suggest that the aging heart does not normally undergo substantial alterations in passive properties that affect the muscle cells and fibers themselves, but rather that the observed changes in compliance are primarily attributable to alterations in ventricular size.
对72只在体外研究的叙利亚金黄地鼠心脏的被动右心室和左心室压力-容积曲线分析表明，中年时心室重量、容积和顺应性增加。两个心室均由注射泵以恒定速率充盈。心室顺应性（dV/dP）通过对心室内压力进行电子微分并形成比率（dV/dt）/（dP/dt）来确定，该比率是心室内压力在0至30 mmHg之间的连续函数。通过合理地将左心室与薄壁弹性球相关联，在心肌壁应力σ的恒定水平下比较不同年龄的心室弹性模量E。弹性模量E被证明是σ的线性函数。E-σ图的斜率为每个年龄组得出一个刚度常数K。体重、心脏重量、舒张末期容积和dV/dP均随年龄增长先增加超过200%然后下降，但K不是年龄的显著函数。这些结果表明，衰老心脏的被动特性通常不会发生影响肌肉细胞和纤维本身的实质性改变，而是观察到的顺应性变化主要归因于心室大小的改变。
