Validation of Noninvasive Epi- Endocardial Electrocardiographic Imaging Accuracy Using Right Ventricular Endocardial Pacing

Invasive electroanatomical mapping of polymorphic and unstable ventricular arrhythmias is a complex and laborious task. Noninvasive epi-endocardial ElectroCardioGraphic Imaging (ECGI) is a novel beat-to-beat mapping technique. The present work is a second part of single-center single-blind cross-sectional study to verify epi-endocardial ECGI accuracy. This part is particularly dedicated to investigate ECGI accuracy during right ventricular endocardial pacing followed by polygon model quality assessment and detailed analysis of cumulative effect of many different factors. Methods. 37 patients with previously implanted pacemakers were enrolled in the study. All patients underwent epiendocardial ECGI mapping (Amycard 01C EP Lab, Amycard LLC, Russia - EP Solutions SA, Switzerland) during right endocardial ventricular pacing. The data obtained from torso and ECG-gated cardiac computed tomography (Somatom Definition 128, Siemens AG, Germany) were used to create three-dimensional ventricular models. Geodesic distance between noninvasively reconstructed early activate zone on the isopotential maps and RV reference pacing site were measured to evaluate ECGI accuracy for each patient. Results. The mean (SD) geodesic distance between noninvasively reconstructed and reference pacing site was 23 (14) mm for RV epicardial models and 9 (12) for RV endocardial surface of epi-endocardial models, median (25-75% IQR) - 21 (11-32) мм and 4 (2-8) mm respectively. ECGI accuracy on RV endocardial surface of epi-endocardial models was significantly better than on epicardial models (p <0,001). At the same time, there were no significant associations between cardiac CT, pacing parameters, clinical characteristics and accuracy values. Conclusions. The main results showed a possibility of novel epi-endocardial ECGI mapping to detect RV focal arrhythmias with high accuracy (median 3 mm) and to recognize endocardial localization with high percent of probability (more than 94%) comparable with invasive electroanatomical mapping. Therefore, this study confirms sufficient accuracy of epi-endocardial ECGI mapping technology for non-invasive topical diagnosis of RV focal arrhythmias.