Myocardium passive mechanical response has been a major topic of study for decades due to its major impact on cardiac physiology. Here, we propose a novel modeling methodology that integrates both in vivo and in vitro data to estimate the tissue mechanical parameters for a particular orthotropic hyperelastic model as those proposed by Costa and by Holzapfel & Ogden, although it can be easily extended to any other. In vitro biaxial and triaxial shear extension tests were conducted in biopsied samples and in vivo pressure-volume recordings were obtained. Left ventricle (LV) geometry was reconstructed using magnetic resonance imaging (MRI) and pressure gradients during ventricular inflation were recorded with the Catheter Conductance Method (CCM). Finally, a Finite Element (FE) in vivo LV model was implemented to get the material model parameters using an inverse approach that uses a minimization process combining both the in vivo and in vitro available data. Our results demonstrate that the parameters obtained solely from in vitro testing (IVT), or from in vivo passive inflation (IVV) do not provide satisfactory fits for both responses simultaneously (${R^2}_{IVT}^{tests}=0.977,{R^2}_{IVT}^{PV}=0.697$ and ${R^2}_{IVV}^{tests}=0.687,{R^2}_{IVV}^{PV}=0.995$). On the contrary, the proposed combined in vitro & in vivo optimization process (MIN) converges to a solution that effectively captures both the in vivo and in vitro behaviors $({R^2}_{MIN}^{tests}=0.815,{R^2}_{MIN}^{PV}=0.992$). Thus, this novel combined approach offers a comprehensive framework for accurately characterizing myocardial mechanical behavior. The obtained parameters can serve as a basis for further cardiac simulations and contribute to a better understanding of cardiac mechanics and function.

心肌被动机械反应由于其对心脏生理学的重大影响，几十年来一直是研究的主要课题。在这里，我们提出了一种新颖的建模方法，该方法集成了体内和体外数据，以估计特定正交各向异性超弹性模型的组织力学参数，如 Costa 和 Holzapfel & Ogden 提出的模型，尽管它可以轻松扩展到任何其他模型。在活检样品中进行体外双轴和三轴剪切延伸测试，并获得体内压力-体积记录。使用磁共振成像（MRI）重建左心室（LV）几何形状，并使用导管电导法（CCM）记录心室膨胀期间的压力梯度。最后，实施有限元 (FE)体内LV 模型，使用逆向方法获取材料模型参数，该逆向方法使用结合体内和体外可用数据的最小化过程。我们的结果表明，仅从体外测试（IVT）或体内被动充气（IVV）获得的参数不能同时为两种反应提供令人满意的拟合（${{右}^2}_{我V\mathrm{时间}}^{tests}=0.977,{{右}^2}_{我V\mathrm{时间}}^{磷V}=0.697$和${{右}^2}_{我VV}^{tests}=0.687,{{右}^2}_{我VV}^{磷V}=0.995$）。相反，所提出的体外和体内组合优化过程（MIN）收敛到一个有效捕获体内和体外行为的解决方案$（{{右}^2}_{\mathrm{中号}我氮}^{tests}=0.815,{{右}^2}_{\mathrm{中号}我氮}^{磷V}=0.992$）。因此，这种新颖的组合方法为准确表征心肌机械行为提供了一个全面的框架。获得的参数可以作为进一步心脏模拟的基础，并有助于更好地理解心脏力学和功能。