Three-dimensional transmural omnipolar mapping: establishing a new paradigm in cardiac electrophysiology
E Ramirez, J Tonko, R Alos, J Millet, F CastellsAbstract
Background
Omnipolar technology together with high density catheters has gained relevance for electroanatomical mapping due to its independence of the wavefront propagation direction. However, current implementations of omnipolar electrograms (EGMs) are limited to a single layer, either endocardial or epicardial.
Purpose
In this proof-of-concept study, we present the reconstruction of three-dimensional omnipolar EGMs by integrating endocardial and epicardial recordings to resolve transmural mapping.
Methods
In-silico simulations of three-dimensional meshes composed of a 4×4×4 electrode array were developed with two interelectrode spacings: (1) 0.1 mm to assess quasi-ideal spatial gradients, and (2) 4 mm to reproduce realistic conditions consistent with standard commercial multielectrode catheters. The propagation direction was varied across multiple incidence angles covering the full 3D sphere, and conduction velocities were simulated within a range of 0.1 to 1.5 m/s . For each simulation the proposed 3D omnipolar EGM was computed by extending 2D omnipolar techniques into a 3D framework. At each inner node of the cubic array, a 3D activation loop was obtained, from which the omnipolar EGM was computed as the projection of the activation onto the three-dimensional propagation vector. Omnipolar EGM reconstruction was evaluated by comparing it with the temporal derivative of the corresponding unipolar EGM, considered the ground truth. Finally, the clinical translational applicability of this approach is illustrated in recordings obtained from a combined endocardial-epicardial ventricular ablation procedure, where unipolar interpolation was used to generate a regular 3D mesh for subsequent analysis.
Results
A total of 4,374 simulations were performed. The proposed method successfully estimated a three-dimensional omnipolar with a root mean square error (RMSE) of 0.0258±0.0003 mV and a Pearson Correlation Coefficient (PCC) of 99.97±0.03% in the 0.1 mm configuration. In the 4 mm scenario, the RMSE increased to 0.1536±0.1295 mV, with a corresponding PCC of 86.54±20.72%. These findings indicate that the computed omnipolar closely corresponds to the true omnipolar EGM, and that larger interelectrode spacing degrades estimation accuracy. The translation of the initial validation of 3D omnipolar EGMs from geometric simulations to clinical data highlights both the feasibility and robustness of the proposed approach for characterizing transmural electrical activation.
Conclusions
This study introduces and validates a proof-of-concept for transmural omnipolar mapping, representing, to our knowledge, the first description of a 3D omnipolar EGM in the literature. The proposed methodology offers a novel framework for comprehensive characterization of myocardial electrical activity, with potential implications for understanding intramural propagation and provide insight for the diagnosis and treatment of complex cardiac arrhythmias.