Non-invasive electrocardiographic ventricular mapping based on the equivalent double layer model: different workflows, same accuracy
Authors: Parreira L , Restrepo A , Ernst S , Da Costa A , Voss U , Hunnybun D , Carmo P , Nunes S , Hitchen R , Martinez M , Adragao P 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background and aim
Electrocardiographic imaging (ECGI) is capable of performing activation maps with a single premature beat. The endo-epicardial ECGI system based on the equivalent double layer model (EDL), is a portable system that uses a patient-specific heart torso geometry obtained from a CT-scan or cardiac magnetic resonance (CMR), and a conventional 12-lead ECG. The simplicity of the system allows for its use either as a pre-procedural or intra-procedural tool. The aim of this study was to assess the accuracy of the system in centres using different workflows.

Methods
We studied consecutive patients referred for ablation of ventricular arrhythmias that had an ECGI performed with the endo-epicardial system based on the EDL model to guide mapping and catheter ablation, at four centres. Three centres performed the ECGI pre-procedurally, two with the use of a bedside portable ECG recorder and one on ambulatory basis with a 12-lead Holter recorder, and ablation was performed either manually or with remote magnetic navigation (RMN). The fourth centre performed the ECGI intra-procedurally, recording the ECG directly from the electrophysiology digital multichannel system, and the ablation was performed manually with the use of intracardiac echo (ICE) in all cases. VAs were localised using a segmental model, which included 22 left ventricular segments (classical 17-segment model, plus the aortic cusps and the papillary muscles), and 12 segments on the right ventricle including 4 on the right ventricular outflow tract (RVOT): Anterior, lateral, right septum and left septum. A perfect match (PM) was defined as a predicted location within the same anatomic segment, whereas a near match (NM) was defined as a predicted location within the same segment or a contiguous one. We studied the three different workflows.

Results
Sixty-three arrhythmias were studied in 58 patients. The ECGI was performed pre-procedurally with a bedside ECG recorder in 26 cases, pre-procedurally with a Holter recorder in 27 cases and intra-procedurally in 10 cases. The results according to each group are presented in the Table. The accuracy of the ECGI was not different between groups. The system correctly identified the SOO of the VAs in the same or a contiguous segment when compared to the invasive mapping in all patients, regardless of the approach used. The percentage of PM was also not significantly different. The group with ICE guidance had lower fluoroscopy and mapping times, but the success and recurrence rates were similar.

Conclusions
The results of this multicentre experience show that this ECGI system, using a conventional 12 -lead ECG is simple and accurate across different clinical workflows, and presents a useful and versatile tool to facilitate planning the ablation strategy as well as intra-procedural guidance for mapping and ablation of patients with VAs.