Diastolic dysfunction (DD) is a major component of heart failure with preserved ejection fraction (HFpEF). Accordingly, a profound understanding of the underlying biomechanical mechanisms involved in DD is needed in order to elucidate all aspects of HFpEF. In this study, we have developed a computational model of DD by leveraging the power of an advanced one-dimensional (1D) arterial network coupled to a four-chambered 0D cardiac model. The two main pathologies investigated were linked to the active relaxation of the myocardium and the passive stiffness of the left ventricular wall. These pathologies were quantified through two parameters for the biphasic delay of active relaxation, which simulate the early and late phase relaxation delay, and one parameter for passive stiffness, which simulates the increased non-linear stiffness of the ventricular wall. A parameter sensitivity analysis was conducted on each of the three parameters to investigate their effect in isolation. The three parameters were then concurrently adjusted to produce the three main phenotypes of DD. It was found that the Impaired Relaxation (IR) phenotype can be replicated by mainly manipulating the active relaxation, the Pseudo-Normal (PN) phenotype was replicated by manipulating both the active relaxation and passive stiffness, and, finally, the Restricted (R) phenotype was replicated by mainly changing the passive stiffness. This paper presents a simple model producing a holistic and comprehensive replication of the main DD phenotypes and presents novel biomechanical insights on how key parameters defining the relaxation and stiffness properties of the myocardium affect the development and manifestation of DD.

中文翻译：

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舒张功能不全的生物力学：一维计算建模方法。

舒张功能障碍（DD）是心力衰竭的主要组成部分，其射血分数（HFpEF）保持不变。因此，为了阐明HFpEF的所有方面，需要对DD中涉及的潜在生物力学机制有深刻的理解。在这项研究中，我们通过利用先进的一维（1D）动脉网络与四腔0D心脏模型耦合的能力，开发了DD的计算模型。研究的两种主要病理与心肌的主动舒张和左心室壁的被动僵硬有关。通过用于主动松弛的两相延迟的两个参数（模拟了早期和晚期相位松弛延迟）和用于被动刚度的一个参数来量化这些病理 模拟心室壁的非线性刚度增加。对这三个参数中的每一个进行了参数敏感性分析，以单独研究它们的作用。然后同时调整这三个参数以产生DD的三个主要表型。发现可以通过主要操纵主动松弛来复制受损松弛（IR）表型，通过操纵主动松弛和被动刚度来复制伪-正常（PN）表型，最后，是限制性（R）表型。通过主要改变被动刚度来复制表型。