A new paper from the group has been accepted for publication
|The paper «Blind Analysis of Atrial Fibrillation Electrograms: Sparsity-Aware Formulation» by D. Luengo, S. Monzon, T. Triganoz, J. Via and A. Artés-Rodríguez has been accepted for publication by the Journal of Integrated Computer-Aided Engineering.|
The problems of blind sparse analysis of electrogram (EGM) signals under atrial fibrillation (AF) conditions is considered in this paper. First of all, a mathematical model for the observed signals that takes into account the multiple foci typically appearing inside the heart during AF is introduced. Then, a reconstruction model based on a fixed dictionary is developed and several alternatives for choosing the dictionary are discussed. In order to obtain a sparse solution, which takes into account the biological restrictions of the problem at the same time, the paper proposes using LASSO regularization followed by a post-processing stage that removes low amplitude coefficients violating the refractory period characteristic of cardiac cells. Finally, spectral analysis is performed on the clean activation sequence obtained from the sparse learning stage in order to estimate the number of latent foci and their frequencies. Simulations on synthetic and real data are provided to validate the proposed approach.