Forward problem of electrocardiography in terms of 3D transmembrane potentials using comsol

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Elektrik ve Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2015

Öğrenci: GİZEM BEDİR

Danışman: YEŞİM SERİNAĞAOĞLU DOĞRUSÖZ

Özet:

Computation of body surface potentials from equivalent cardiac sources is called as forward problem of electrocardiography (ECG). There exist different solution meth- ods for solving the forward ECG problem. These solution methods depend on the choice of the equivalent cardiac sources. In this study, bidomain model based trans- membrane potential (TMP) distribution is used as equivalent cardiac source to exam- ine the cellular electrophysiology macroscopically. With this type of source defini- tion, the TMP values are linearly related to the body surface potentials, and this linear relationship is modeled by a forward transfer matrix, T. Then the forward problem of ECG is solved in order to obtain T, using finite element method (FEM). In the first part of this study, both the heart and torso are assumed as two concentric spheres and electrically isotropic regions. First forward problem of ECG is solved both analytically and numerically, and then a transfer matrix that relates the TMPs to the body surface potentials is constructed. Accuracy of the transfer matrix is ver- ified by the analytical solution. Numerical solutions are done using COMSOL Mul- tiphysics Software which provides easy mesh generation by discretizing the solution domain with FEM. Flexibility of arranging both mesh element sizes and numbers in the solution domain makes COMSOL preferable for this study. In the second part of the study, a spherical heart is placed inside a realistic torso geometry and the forward problem is solved again to obtain the transfer matrix.