Fusion Imaging of Non-Invasive and Invasive Cardiac Electroanatomic Mapping in Patients with Ventricular Ectopic Beats: A Feasibility Analysis in a Case Series

Abstract

In patients with premature ventricular contractions (PVCs), non-invasive mapping could locate the PVCs' origin on a personalized 3-dimensional (3D) heart model and, thus, facilitate catheter ablation therapy planning. The aim of our report is to evaluate its accuracy compared to invasive mapping in terms of assessing the PVCs' early activation zone (EAZ). For this purpose, non-invasive electrocardiographic imaging (ECGI) was performed using the Amycard 01C system (EP Solutions SA, Switzerland) in three cases. In the first step, a multichannel ECG (up to 224 electrodes) was recorded, and the dominant PVCs were registered. Afterward, a cardiac computed tomography (in two cases) or magnetic resonance imaging (in one case) investigation was carried out acquiring non-contrast torso scans for 8-electrode strip visualization and contrast heart acquisition. For the reconstructed epi/endocardial meshes of the heart, non-invasive isochronal maps were generated for the selected multichannel ECG fragments. Then, the patients underwent an invasive electrophysiological study, and the PVCs' activation was evaluated by a 3D mapping system (EnSite NavX Precision, Abbott). Finally, using custom-written software, we performed 3D fusion of the non-invasive and invasive models and compared the resulting isochronal maps. A qualitative analysis in each case showed the same early localization of the dominant PVC on the endocardial surface when comparing the non-invasive and invasive isochronal maps. The distance from the EAZ to the mitral or tricuspid annulus was comparable in the invasive/non-invasive data (36/41 mm in case N1, 73/75 mm in case N2, 9/12 mm in case N3). The area of EAZ was also similar between the invasive/non-invasive maps (4.3/4.5 cm² in case N1, 7.1/7.0 cm² in case N2, 0.4/0.6 cm² in case N3). The distances from the non-invasive to invasive earliest activation site were 4 mm in case N1, 7 mm in case N2, and 4 mm in case N3. Such results were appropriate to trust the clinical value of the preoperative data in these cases. In conclusion, the non-invasive identification of PVCs before an invasive electrophysiological study can guide clinical and interventional decisions, demonstrating appropriate accuracy in the estimation of focus origin.

Keywords: electroanatomic mapping; fusion imaging; non-invasive electrocardiographic imaging; ventricular ectopic beats.

Figure 1

Case N1. Sinus rhythm, monomorphic premature ventricular contractions with bigeminy pattern.

Figure 2

Schematic representation of the workflow, starting from the electrocardiographic (ECG) registration, proceeding to imaging and 3D segmentation, to invasive mapping, and, finally, to the fusion imaging of non-invasive and invasive data.

Figure 3

Upper row: example of recording computer tomography (CT). (A,B)—CT torso acquisition to capture applied metal 8-electrode strips (‘LungLowDose’ scan without contrast); (C)—contrast CT heart acquisition. Lower row: example of recording magnetic resonance imaging (MRI). (D,E)—torso series (t1_vibe_fs_cor_bh) in coronal plane to capture applied carbon MRI-compatible 8-electrode strips; (F)—MRI contrast heart acquisition with t1_vibe_fs_tra_p2_bh_iso_320 sequence.

Figure 4

Case N1. Sinus rhythm, premature ventricular contraction. Three-dimensional representation of the non-invasive isochronal map on the left, and of the invasive isochronal map on the right. EAZ—early activation zone (red color). Approximately 41 mm distance from EAZ to mitral annulus on non-invasive isochronal map; 36 mm distance from EAZ to mitral annulus on invasive isochronal map.

Figure 5

Case N1. Sinus rhythm, premature ventricular contraction. Three-dimensional representation of the endocardial non-invasive isochronal map on the left, of the invasive isochronal map in the middle, and the fusion of non-invasive and invasive maps on the right. EAZ—early activation zone. White marker—the earliest activation site of EAZ. Approximately 4 mm distance between non-invasive and invasive earliest activation site on fusion model.

Figure 6

Case N2. Sinus rhythm, monomorphic premature ventricular contractions with bigeminy pattern and right bundle branch morphology.

Figure 7

Case N2. Sinus rhythm, premature ventricular contraction. Three-dimensional representation of the endocardial non-invasive isochronal map on the left, of the invasive isochronal map in the middle, and the fusion of non-invasive and invasive maps on the right. EAZ—early activation zone. White marker—the earliest activation site of EAZ. Approximately 7 mm distance between non-invasive and invasive earliest activation site on fusion model.

Figure 8

Case N3. Sinus rhythm, monomorphic premature ventricular contractions.

Figure 9

Case N3. Sinus rhythm, premature ventricular contraction. Three-dimensional representation of the endocardial non-invasive isochronal map on the left, of the invasive isochronal map in the middle, and the fusion of non-invasive and invasive maps on the right. EAZ—early activation zone; LV—left ventricle; RV—right ventricle; RVOT—right ventricular outflow tract. White marker—the earliest activation site of EAZ. Approximately 4 mm distance between non-invasive and invasive earliest activation site on fusion model.