Passive characteristics of conditioned skeletal muscle for ventricular assistance.
Passive characteristics of conditioned skeletal muscle for ventricular assistance.
复制标题
条件骨骼肌用于心室辅助的被动特征。
DOI：
10.1097/00002480-199907000-00017
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Hill,JD
中科院分区：
文献类型：
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作者：
Reichenbach,SH;Farrar,DJ;Hill,JD
以骨骼肌为动力驱动心室辅助装置（VAD）的系统已经提出并正在开发中。在VAD填充期间，这些系统必须对抗被动肌肉力来控制预收缩长度并优化功率输出。为了确定电刺激的肌肉调节如何改变基本的生物力学特征和影响可用功率，在植入肌刺激器训练8周后，对山羊背阔肌进行了体内评估。条件性肌肉表现出增加的被动僵硬。调节后，在被动力为10 N时，指数被动力-长度关系的斜率从5.1 N/cm显著增加到7.6 N/cm （p= 0.003）。同样，当被动力为10 N时，相对于零发展力长度，长度从5.5 cm减少到4.2 cm （p< 0.014）。斜率（dF/dL）和力(F)之间的线性关系也表现出显著的截距偏移。后一种关系与绝对长度无关。与其他研究一致的是，调节也会导致抗疲劳性、纤维类型转变、最大发展力和缩短速度的降低。在心脏辅助可用功率的情况下，研究结果表明，被动特性的影响在调节后会加剧，并且对可用功率有实质性影响。ASAIO Journal 1999；45: 344 - 349。
Systems to drive a ventricular assist device (VAD) with power from skeletal muscle have been proposed and are under development. During VAD filling, these systems must counter passive muscle force to control the precontraction length and optimize power output. To determine how muscle conditioning with electrical stimulation alters basic biomechanical characteristics and influences available power, goat latissimus dorsi were evaluated in vivo after an 8 week training protocol with an implanted myostimulator. Conditioned muscles displayed increased passive stiffness. After conditioning, the slope of the exponential passive force-length relation, at a passive force of 10 N, significantly increased from 5.1 to 7.6 N/cm (p= 0.003). Similarly, for a passive force of 10 N, the length relative to the zero developed force length decreased from 5.5 to 4.2 cm (p< 0.014). The linear relationship between slope (dF/dL) and force (F) also demonstrated a significant intercept shift. The latter relationship is independent of absolute length. Consistent with other studies, conditioning also resulted in fatigue resistance, fiber type transformation, and reductions in maximum developed force and shortening velocity. In the context of available power for cardiac assist, the results demonstrate that the influence of passive characteristics is accentuated after conditioning and has a substantial effect on available power. ASAIO Journal 1999; 45: 344–349.