Physiology-based regularization improves noninvasive reconstruction and localization of cardiac electrical activity

The objective of the inverse problem of electrocardiography is to noninvasively reconstruct information about electrical activity at the heart surface (epicardium), from electrical measurements on the body surface and a patient-specific torso-heart geometry. This is complicated by the ill-posedness of the inverse problem. Previously, we have shown that a realistic basis can be created from (simulated) epicardial training potentials. Potentials reconstructed with traditional methods can be projected onto this basis, improving the quality of reconstructions. Here, we propose a novel superior method called `physiology-based regularization' that renders traditional reconstruction and projection unnecessary. Instead, reconstruction of epicardial electrograms is achieved directly, by pursuing a sparse representation in terms of this realistic basis. We validate this method by invasive epicardial electrogram recordings in a canine experiment. We further demonstrate that by creating a realistic basis for a specific purpose, this method can answer clinical questions with improved accuracy. Ultimately, physiology-based regularization would improve patient care by yielding patient-specific results, inspired by electrophysiological knowledge and optimized to answer clinically relevant questions.