Computational modeling of cardiac dysfunctions

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2014

Öğrenci: EZGİ BERBEROĞLU YILMAZ

Danışman: SERDAR GÖKTEPE

Özet:

Computational modeling of the cardiovascular system has improved remarkably with the advances in the computer technology and mathematical modeling. The cardiac models can play a crucial role in understanding the major electromechanical, biophysical, and biochemical processes for the both healthy and pathological cases. The capability of heart models to capture the real physiological behavior depends on physiologically sound constitutive models accounting for the intrinsically non-linear, electromechanically coupled response of anisotropic cardiac tissue. It is also necessary to incorporate the efficient, robust, and stable numerical algorithms into these models. To this end, we propose a micro-structurally based, unified implicit finite element approach to the fully coupled problem of cardiac electromechanics incorporating cardiac dysfunctions. In this thesis, we formulate the coupled problem of cardiac electromechanics through the conservation of linear momentum and the excitation equation in the Eulerian setting. These equations are solved monolithically through an entirely finite element-based implicit algorithm. Different from the existing literature, the deformation gradient is multiplicatively decomposed into active and passive parts in addition to the additive split of the free energy function to model the electromechanical coupling. This framework allows us to combine the advantages of the active-stress and the active-strain approaches. The left ventricular pressure evolution is modeled by incorporating a Windkessel-like model. The proposed model is then employed to investigate different pathological cases that cover myocardial infarction, eccentric and concentric hypertrophy. The computational results are shown to be in agreement with the clinical symptoms observed in the associated dysfunction.