The heart is a muscular organ which acts as a biomechanical pump. Electrical impulses are generated in specialized cells and flow through the heart myocardium by the ion changes on the cell membrane which is the beginning of both the electrical and the mechanical activity. Both the electrical and the mechanical states of the organ will directly affect the pumping activity. The main motivation of this thesis is to better understand physiological and pathological properties of the heart muscle via studying the electro-mechanics of the heart. This model could be used to gain better solutions of the ill-posed inverse problem of ECG and Body Surface Potential Maps (BSPM) or to estimate the electrical propagation and mechanical response on patient specific heart geometry models which can be obtained by using MRI technique. Cellular automaton technique will be used to simulate the physiological function of the left ventricle to estimate the cardiac functions. To model the heart tissue firstly the anatomical knowledge of the heart will be used such as properties of the myocardium, fiber orientations, etc. to simulate the three dimensional electrical propagation. Then the mechanical activity consisting of contraction and relaxation will be simulated according to the material properties of the heart. Using this simulation, the effects of the cardiac arrhythmias such as reentry will be generated.
In this study, electrical and mechanical properties of the heart tissue are modeled for normal heart beat and heart beat in case of ischemic heart tissue. Contraction of the tissue via electrical activation has also been considered in terms of time synchronization. &ldquo / Cellular automaton&rdquo / method is used for modeling the electromechanical interactions in the heart tissue. A simplified
left ventricle model is used to observe the electrical and the mechanical behavior. Using this method, both the normal heart beat&rsquo / s electrical activation and the arrhythmia excitation could be taken on, without using complex differential equations. To consider the anisotropy of the heart tissue, fiber orientations have also been added to the model. In this thesis work, electro-mechanic models at cellular, macroscopic and heart left ventricle level are presented. The electro-mechanical adaptation is performed by cellular electrophysiology and cellular force development due to intercellular excitation propagation. Varying densities of transmembrane proteins, changes on concentration of calcium, metabolic and hormonal effects are neglected. Also in simplified ventricular model the fluid mechanics and mechanoelectrical feed-back is not taken into-account.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12612657/index.pdf |
| Date | 01 October 2010 |
| Creators | Bora, Ceren |
| Contributors | Serinagaoglu Dogrusoz, Yesim |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
Page generated in 0.0113 seconds