Comparison of dipole-based and potential-based ECGI methods for premature ventricular contraction beat localization with clinical data

Abstract

Introduction: Localization of premature ventricular contraction (PVC) origin to guide the radiofrequency ablation (RFA) procedure is one of the prominent clinical goals of non-invasive electrocardiographic imaging. However, the results reported in the literature vary significantly depending on the source model and the level of complexity in the forward model. This study aims to compare the paced and spontaneous PVC localization performances of dipole-based and potential-based source models and corresponding inverse methods using the same clinical data and to evaluate the effects of torso inhomogeneities on these performances.Methods: The publicly available EP solution data from the EDGAR data repository (BSPs from a maximum of 240 electrodes) with known pacing locations and the Bratislava data (BSPs in 128 leads) with spontaneous PVCs from patients who underwent successful RFA procedures were used. Homogeneous and inhomogeneous torso models and corresponding forward problem solutions were used to relate sources on the closed epicardial and epicardial–endocardial surfaces. The localization error (LE) between the true and estimated pacing site/PVC origin was evaluated.Results: For paced data, the median LE values were 25.2 and 13.9 mm for the dipole-based and potential-based models, respectively. These median LE values were higher for the spontaneous PVC data: 30.2–33.0 mm for the dipole-based model and 28.9–39.2 mm for the potential-based model. The assumption of inhomogeneities in the torso model did not change the dipole-based solutions much, but using an inhomogeneous model improved the potential-based solutions on the epicardial–endocardial ventricular surface.Conclusion: For the specific task of localization of pacing site/PVC origin, the dipole-based source model is more stable and robust than the potential-based source model. The torso inhomogeneities affect the performances of PVC origin localization in each source model differently. Hence, care must be taken in generating patient-specific geometric and forward models depending on the source model representation used in electrocardiographic imaging (ECGI).

A two-step inverse solution for a single dipole cardiac source

“…The first inverse solution was computed using all 128 electrodes. Our results in Table 2 indicated that using a homogeneous volume conductor slightly improves the localization (28.6 ± 12.1 mm vs. 29.0 ± 12.1 mm) which is consistent with our previous findings reported for a single dipole cardiac source (Dogrusoz et al, 2023). Then, the significance of the torso electrodes for each patient was estimated from the transfer matrix corresponding to the inversely computed origin of the PVC as it was shown that the positions of the most significant electrodes vary between patients, and they depend on the origin of the PVC (Ondrusova et al, 2021).…”

“…The first inverse solution was computed using all 128 electrodes. Our results in Table 2 indicated that using a homogeneous volume conductor slightly improves the localization (28.6 ± 12.1 mm vs. 29.0 ± 12.1 mm) which is consistent with our previous findings reported for a single dipole cardiac source ( Dogrusoz et al, 2023 ).…”

“…This could explain why a high LE was observed for some patients. In a prior study involving a single dipole cardiac source, we documented an LE of 24.5 ± 4.1 mm for the inverse solutions calculated using data with a clearly defined ground truth ( Dogrusoz et al, 2023 ). Notably, this LE was lower and exhibited a more confined range of standard deviations in contrast to the current study’s results, which reported an LE of 28.6 ± 12.1 mm for the homogeneous volume model.…”

“…For this position, the significance of the electrodes was estimated from the singular values obtained from the SVD of the transfer matrix. The average localization error of inverse solution using a single dipole cardiac source is 20–30 mm ( Svehlikova et al, 2018 ; Dogrusoz et al, 2023 ). Therefore, we assumed that the significance of the electrodes for the position of the first inverse solution would be similar to the significance of the electrodes for the position of the ground truth if these two positions are not too far apart ( Ondrusova et al, 2023 ).…”