Boundary element formulation and its solution in forward problem of electrocardiography by using a realistic torso model

Abstract

The electrical currents generated in the heart propagate to the outward directionof the body by means of conductive tissues and these currents yield a potentialdistribution on the body surface. This potential distribution is recordedand analyzed by a tool called electrocardiogram. It is not a problem, if this processcontinues normally; however, when it is distorted by some abnormalities,the results will be fatal. Electrocardiography (ECG) is the technique dealingwith the acquisition and interpretation of the electrical potentials recorded atthe body surface due to the electrical activity of the heart. This can be realizedby using one of the two approaches utilized in ECG namely; forward and inverseproblems. The former one entails the calculation potentials on the body surfacefrom known electrical activity of the heart and the latter one does the reverse.In this thesis, we will construct the body surface potentials in a realistic torsomodel starting from the epicardial potentials. In order to solve the forwardproblem, one needs a geometric model that includes the torso and the heartsurfaces, as well as the intermediate surfaces or the intervening volume, andsome assumptions about the electrical conductivity inside the enclosed volume.A realistic torso model has a complex geometry and this complexity makes itimpossible to solve the forward problem analytically. In this study, BoundaryElement Method (BEM) will be applied to solve the forward problem numerically.Furthermore, the effect of torso inhomogeneities such as lungs, musclesand skin to the body surface potentials will be analyzed numerically.Keywords: Forward problem, boundary element method, realistic torso model.