Different Passive Viscoelastic Properties Between the Left and Right Ventricles in Healthy Adult Ovine
Different Passive Viscoelastic Properties Between the Left and Right Ventricles in Healthy Adult Ovine
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DOI：
10.1115/1.4052004
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发表时间：
2021-12-01
影响因子：
1.7
通讯作者：
Wang, Zhijie
中科院分区：
文献类型：
--
作者：
Liu, Wenqiang;Nguyen-Truong, Michael;Wang, Zhijie
心功能不全是心力衰竭最常见的原因，导致高死亡率和高发病率。心室的力学行为对其生理功能至关重要。众所周知，心室是各向异性和粘弹性的。然而，人们对心室粘弹性的认识远不如对心室弹性的认识。此外，左、右心室（LV&RV）在胚胎起源、解剖和功能上不同，但它们在粘弹性方面是否有区别尚不清楚。我们假设，被动粘弹性是不同的健康的LV和RV。对健康成年绵羊心室进行体外循环双向拉伸力学试验（1、0.1、0.01 Hz）和应力松弛（应变为3、6、9、12、15%）。流出轨迹方向定义为纵向。获得了滞后应力-应变环和应力松弛曲线，以量化粘弹性能。我们发现，RV比LV具有更明显的频率依赖性粘弹性变化。在生理频率（1Hz）下，左心室的弹性各向异性更强，在两个方向上的刚度都大于右心室，而右心室的粘性各向异性更强，在纵向上的粘性大于左心室。LV在纵向上是准线性粘弹性的，而不是周向，RV在两个方向上都是非线性粘弹性的。本研究首次探讨了健康左心室和右心室的被动粘弹性差异，研究结果将加深对心室功能生物力学机制的理解。
Ventricle dysfunction is the most common cause of heart failure, which leads to high mortality and morbidity. The mechanical behavior of the ventricle is critical to its physiological function. It is known that the ventricle is anisotropic and viscoelastic. However, the understanding of ventricular viscoelasticity is much less than that of its elasticity. Moreover, the left and right ventricles (LV&RV) are different in embryologic origin, anatomy, and function, but whether they distinguish in viscoelastic properties is unclear. We hypothesized that passive viscoelasticity is different between healthy LVs and RVs. Ex vivo cyclic biaxial tensile mechanical tests (1, 0.1, 0.01 Hz) and stress relaxation (strain of 3, 6, 9, 12, 15%) were performed for ventricles from healthy adult sheep. Outflow track direction was defined as the longitudinal direction. Hysteresis stress-strain loops and stress relaxation curves were obtained to quantify the viscoelastic properties. We found that the RV had more pronounced frequency-dependent viscoelastic changes than the LV. Under the physiological frequency (1 Hz), the LV was more anisotropic in the elasticity and stiffer than the RV in both directions, whereas the RV was more anisotropic in the viscosity and more viscous than the LV in the longitudinal direction. The LV was quasi-linear viscoelastic in the longitudinal but not circumferential direction, and the RV was nonlinear viscoelastic in both directions. This study is the first to investigate passive viscoelastic differences in healthy LVs and RVs, and the findings will deepen the understanding of biomechanical mechanisms of ventricular function.