Natarajan G, Bove A A, Coulson R L, Carey R A, Spann J F
Am J Physiol. 1979 Dec;237(6):H676-80. doi: 10.1152/ajpheart.1979.237.6.H676.
The passive stress-strain relationship of right ventricular papillary muscles from 10 normal and 9 experimental cats with short-term pressure-overload right ventricular hypertrophy-failure was examined by plotting the logarithm of instantaneous stress (ln sigma) against the natural strain calculated as ln(l/l0) where l = instantaneous length and l0 = length at zero force. Such a stress-strain relationship was well approximated by a linear relationship. The slope K obtained from this linear relationship was higher in the hypertrophy-failure muscles (normal, 15.01 +/- 0.87 (SEM); hypertrophy-failure, 31.79 +/- 4.09; P less than 0.005). The value of the intercept, ln C was similar in the two groups (normal, -4.33 +/- 0.20; hypertrophy-failure, -4.71 +/- 0.10). This analysis indicates the the ln sigma-natural strain relationship is linear in the papillary muscle and the slope of this relationship, an index of stiffness, is increased in hypertrophy-failure muscles. Using a three-element muscle model, it is shown that increased diastolic stiffness may contribute to the decreased systolic performance.
通过绘制瞬时应力的对数（ln σ）与自然应变的关系图，对10只正常猫和9只患有短期压力超负荷性右心室肥大-衰竭的实验猫的右心室乳头肌的被动应力-应变关系进行了研究。自然应变的计算方式为ln(l/l0)，其中l为瞬时长度，l0为零力时的长度。这种应力-应变关系通过线性关系得到了很好的近似。从这种线性关系中获得的斜率K在肥大-衰竭肌肉中更高（正常组，15.01±0.87（标准误）；肥大-衰竭组，31.79±4.09；P<0.005）。两组的截距ln C值相似（正常组，-4.33±0.20；肥大-衰竭组，-4.71±0.10）。该分析表明，ln σ-自然应变关系在乳头肌中呈线性，且这种关系的斜率（作为刚度指标）在肥大-衰竭肌肉中增加。使用三元肌肉模型表明，舒张期刚度增加可能导致收缩期性能下降。
