Noninvasive epi-endocardial electrocardiographic imaging of ventricular septal pacing

Noninvasive epi-endocardial ElectroCardioGraphic Imaging (ECGI) allows reconstruction of electrograms and high-resolution visualization of various isoparametric maps based on multichannel ECG recordings and tomography. This study shows results of ECGI accuracy verification based on septal ventricular pacing in patients with pre-implanted pacemakers using new algorithm for solving the inverse problem of electrocardiography. Methods . 10 patients in this study underwent epi-endocardial ECGI mapping (Amycard 01C EP Lab, Amycard LLC, Russia - EP Solutions SA, Switzerland). An iterative Equal Single Layer algorithm (ESL-iterative) and new Fast Route algorithm in combination with vector approach (FRA-V) were used to reconstruct isopotential and correlation similarity maps. Geodesic distance between noninvasively reconstructed early activate zone and RV reference pacing site were measured to evaluate ECGI accuracy. Results . The mean (SD) geodesic distance between noninvasively reconstructed and reference pacing site was 22 (15) mm for ESL-iterative and 12 (7) for FRA-V algorithm, median (25-75% IQR) - 23 (8-29) mm and 10 (8-14) mm respectively. Accuracy of ECGI mapping based on FRA-V algorithm was significantly better than ESL-iterative algorithm (p=0,01). Detailed visual analysis of correlation similarity and isopotential maps showed significantly more accurate localization of early activation zones using new FRA-V algorithm. Conclusions . These results showed a possibility of novel epi-endocardial ECGI mapping to detect early activation zone during septal ventricular pacing with sufficient accuracy (median 10 mm) using new FRA-V algorithm. Therefore, FRA-V algorithm is significantly better for epi-endocardial ECGI mapping and shows a significant advantage of this technique compared to other non-invasive methods of topical diagnostics. Moreover, simultaneous beat-to-beat mapping of entire ventricular septum allows using of this technique for preoperative topical diagnosis of complex unstable and polymorphic ventricular arrhythmias.