Volumetric Non-Invasive Cardiac Mapping for Accessible Global Arrhythmia Characterization

TL;DR

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.

Abstract

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.

Figures (9)

• Figure 1: Workflow of volumetric ECGI technology. The process begins with body surface potential acquisition using a multi-electrode vest, capturing electrical signals from the torso. Simultaneously, patient-specific cardiac and torso geometries are estimated. These data are processed through a volumetric transfer matrix, enabling the estimation of cardiac sources throughout the myocardium. Finally, local activation times are computed, generating three-dimensional activation maps that depict the electrical wave propagation within the heart.
• Figure 2: Comparison of local activation times (LATs) derived from different cardiac variables in a simulated PVC beat. The top row presents the governing equation of electrical propagation in the body, with each highlighting the variable under analysis. Middle row shows spatial maps of the variable at a fixed time instant together with temporal traces at a fixed myocardial location. Bottom row shows the derived LAT maps. LATs are computed as the time of maximum upstroke for the action potential, and as the time of maximum positive rate of deflection for both the cardiac source and the electric potential. Although the variables differ in physical meaning, all provide consistent activation patterns across the myocardium.
• Figure 3: Volumetric ECGI activation sequence across multiple horizontal slices of the myocardium. The left panel illustrates the global activation sequence, visualized through horizontal slices, originating from a stimulation site on the left ventricular free wall. The right panel presents six individual slices (a–f), depicting activation propagation at different myocardial depths. Cardiac sources extracted from black, brown, and gray dots correspond to early, intermediate, and late activation times, respectively, showing distinct deflections that align with activation timing at varying depths within the myocardium.
• Figure 4: Comparison of LATs from the gold standard, epicardial and volumetric ECGI for ventricular ectopic beats localization. Activation maps reconstructed using different methodologies are presented in columns: gold standard simulations (left column), epicardial ECGI (middle column), and volumetric ECGI (right column). The rows correspond to three different simulations of ectopic beats originating from the ventricular base (top), free wall (middle), and septum (bottom). Red spheres mark the true and estimated sites of earliest activation.
• Figure 5: Localization errors in PVC detection using epicardial and volumetric ECGI. Boxplots compare Euclidean (solid lines) and geodesic (dashed lines) distance errors for PVC localization across three ventricular regions: base, free wall, and septum. Results are shown for epicardial ECGI (blue) and volumetric ECGI (orange).