Volumetric Non-Invasive Cardiac Mapping for Accessible Global Arrhythmia Characterization

Cardiac arrhythmias are a major cause of morbidity and mortality increasing the risk of stroke, heart failure, and sudden cardiac death. Imageless electrocardiographic imaging (ECGI) provides a non invasive alternative to electrical mapping from body surface potentials, but conventional ECGI is confined to epicardial reconstructions and can miss arrhythmias originating in deeper myocardium. We address this by reconstructing three dimensional cardiac activity with a volumetric formulation that solves an inverse source problem via Green's functions, enabling full volume activation mapping and improved localization in anatomically complex regions. We evaluate the approach on simulated premature ventricular beats and on four challenging patient cases, a right ventricular outflow tract premature ventricular contraction, a left bundle branch block, a ventricular tachycardia, and Wolff Parkinson White, and additionally assess performance on an open source myocardial infarction dataset. Results show that volumetric ECGI recovers 3D activation and sharpens arrhythmia origin localization, achieving a 59.3% reduction in geodesic error between estimated and simulated origins relative to surface only methods; in patient cases, activation patterns align with clinical diagnoses. Overall, imageless volumetric ECGI offers accessible, non invasive 3D activation mapping that overcomes a core limitation of surface restricted techniques and may improve preprocedural planning, ablation target guidance, and selection or optimization of cardiac resynchronization therapy.