Reconstructing Heart's Electrical Activity with Fewer Body Surface Measurements, Papers of Biology

Download Reconstructing Heart's Electrical Activity with Fewer Body Surface Measurements and more Papers Biology in PDF only on Docsity! www.ece.neu.edu/students/aghodrat/research.htm Inverse Electrocardiography (ECG) The idea of inverse electrocardiography is to reconstruct the electrical activity of the heart from the observations on the body surface. This electrical activity in our formulation is represented by the potentials on the heart surface (epicardium). In order to solve the inverse problem we need to have a forward model. The forward model used in our research is potential based and in the discrete form, relates the potentials of the heart surface to the potentials of the torso surface via an ill-conditioned matrix A. y=A*x Where A is forward matrix, x holds heart surface potentials and y holds torso potentials. The forward matrix A is ill-conditioned thus we need regularization in order to get a stable inverse solution. There are standard methods of regularization like Tikhonov and TSVD that are used in inverse ECG problem. One of the challenges is to improve the inverse solution by including temporal information or adding prior physiological knowledge to the problem. Abstract—the goal of the inverse problem of electrocardiography is noninvasive discrimination and characterization of normal/abnormal cardiac electrical activity from measurements of body surface potentials. Smoothing and attenuation in the torso volume conductor cause the problem to be ill posed. Standard regularized solutions employ an a priori constraint to achieve reliability and may be biased by the constraint chosen as well as the regularization parameter used to weight it. Spatial and temporal regularization Standard methods of regularization smooth the inverse solution. In order to prevent the smoothness we need to incorporate prior knowledge to the problem as constraints. These constraints could be temporal that assumes a certain behavior of the solution in time, spatial that assumes a specific model for the potential map or combination of both of them. We use real measurements of the heart to design these constraint.