Three-Dimensional Noninvasive Imaging of Ventricular Arrhythmias in Patients With Premature Ventricular Contractions

Abstract

Objective: Noninvasive imaging of cardiac electrical activity promises to provide important information regarding the underlying arrhythmic substrates for successful ablation intervention and further understanding of the mechanism of such lethal disease. The aim of this study is to evaluate the performance of a novel 3-D cardiac activation imaging technique to noninvasively localize and image origins of focal ventricular arrhythmias in patients undergoing radio frequency ablation.

Methods: Preprocedural ECG gated contrast enhanced cardiac CT images and body surface potential maps were collected from 13 patients within a week prior to the ablation. The electrical activation images were estimated over the 3-D myocardium using a cardiac electric sparse imaging technique, and compared with CARTO activation maps and the ablation sites in the same patients.

Results: Noninvasively-imaged activation sequences were consistent with the CARTO mapping results with an average correlation coefficient of 0.79, average relative error of 0.19, and average relative resolution error of 0.017. The imaged initiation sites of premature ventricular contractions (PVCs) were, on average, within 8 mm of the last successful ablation site and within 3 mm of the nearest ablation site.

Conclusion: The present results demonstrate the excellent performance of the 3-D cardiac activation imaging technique in imaging the activation sequence associated with PVC, and localizing the initial sites of focal ventricular arrhythmias in patients. These promising results suggest that the 3-D cardiac activation imaging technique may become a useful tool for aiding clinical diagnosis and management of ventricular arrhythmias.

Fig 1

Illustrations of cardiac electrical imaging. When a cell activates, the transmembrane potential changes rapidly and generates electrical activity that can travel through the body and be detected by ECG electrodes. With numerical methods such as the boundary element method (BEM), the electrical activity can be reconstructed in the form of equivalent current densities inside the myocardium to visualize the activation pattern of the cardiac depolarization process.

Fig 2

Schematic diagram of the study. A: patients; B: body surface ECG collected pre-surgically including the arrhythmias; C: CT scan with torso and cardiac geometry; D: EP study with catheter ablation by intra-cardiac mapping technique; E: BSPM of the ectopic beats isolated from the ECG recording. F: boundary element model constructed according to the CT geometry; G: 3D co-registration of CARTO geometry and CT endocardium; H: CESI activation in 3D; I: quantitative comparisons between the CARTO mapped activation pattern and the CESI activation pattern on corresponding regions.

Fig 3

The schematic diagram and the statistics of quantitative comparisons between 12-Lead dipole localization and 3D imaging. Panel A: schematic diagram of comparing 3D imaging localizations and 12 Lead based dipole localizations. Panel B: summarized statistics of the 3D imaging localization and 12 lead ECG dipole localization.

Fig 4

Examples of imaging activation sequences during ectopic beats originating from the RV (Panel A) and the LV (Panel B) in two patients. Black circles represent the last successful ablation site. The white star indicates the site of initiation localized by CESI. The left column shows the 3D volumetric view of the myocardium activation. The cross-sections along the axial direction are presented in the middle column. In the right column, the endocardial surface is extracted from the 3D imaged activations and compared with those measured by CARTO.

Fig 5

Examples of PVC ectopic beats originating near the RV free wall (Panel A) and septum (Panel B) in two patients. Black circle represents the last ablated site recorded. The white star indicates the CESI imaged initiation. The left column shows the 3D volumetric view of the myocardium activation. The cross-sections along the axial direction are presented in the middle column. In the right column, the endocardial surface is extracted from the 3D imaged activations and compared with those measured by CARTO.