Magnetic source imaging in the human heart: estimating cardiac electrical sources from simulated and measured magnetocardiogram data

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Abstract
The estimation of pseudo primary current dipoles on a 2D-manifold in the atrial and ventricular myocardium and septum, and of the transmembrane potential on the endocardium and epicardium, from the magnetic heart field is investigated. The human thorax surrounding the heart is modelled by an inhomogeneous boundary element volume conductor model, including the outer thorax surface and the surfaces of the lungs. The influence of the blood mass is neglected. In the inverse problem Tikhonov’s regularisation is applied. The regularisation parameter is determined by the L-curve method. An algorithm for iterative improvement is applied to estimate the pseudo primary current dipoles. Synthetic magnetic field and electric potential data are generated using a cellular automaton model of the entire human heart. Real world magnetic field data for a normal subject are analysed to demonstrate the practicability and effectiveness of the presented method.