Non-invasive electrocardiographic imaging for the characterization of complex atrial tachyarrhythmias
Authors: Reventos-Presmanes J , Invers-Rubio E , Ferro E , Borras R , Regany M , Guillem M S , Guasch E , Tolosana J M , Roca-Luque I , Porta-Sanchez A , Arbelo E , Althoff T , Climent A M , Mont L , Guichard J B 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This work was supported by the European Union NextGenerationEU/PRTR.

Background
– The non-invasive characterization of complex atrial tachyarrhythmias, including atrial flutter (AFL) and focal atrial tachycardia (AT) is challenging. Conventional 12-lead electrocardiogram (ECG) faces several limitations. Planning a precise and preprocedural strategy for complex tachyarrhythmias catheter ablation (CA) is not easy.

Purpose
To evaluate the diagnostic capacity of a novel electrocardiographic imaging (ECGI) system that does not require previous CT/MRI thoracic imaging.

Methods
– 42 patients (27 males, CHA2DS2-VASc score 2±1, LVEF 54.5 ± 11.0 % and LA area 31.3 ± 7.0 cm2) undergoing CA for focal AT or AFL were prospectively included in the study. A preprocedural ECGI was managed based on a 64-electrode vest, a torso reconstruction using a 3D real-time acquisition camera, and an artificial intelligence-based method to estimate the patient atrial geometry. The differential diagnostic capacities of non-invasive 12-lead ECG and ECGI were assessed compared with endocavity electroanatomical mapping (EAM) regarding three endpoints: 1) the identification of the involved atrial cavity, 2) the mechanism (focal/micro-reentry or macro-reentry), and (3) the ablation target site defined as the area where the earliest activation was located for focal/micro re-entrant arrhythmias, and the precise anatomical pathway for macro re-entrant tachyarrhythmias. Regarding the ECG, the three endpoints were assessed based on validated algorithms by 2 different observers blinded from the diagnosis.

Results
– 48 atrial tachyarrhythmias of which 59.5% occurred in the context of a history of CA were evaluated. The non-invasive characterization of complex atrial arrhythmias using this novel ECGI system was possible in 94% of the cases (Figure A): directly for 36 arrhythmias and after decreasing ventricular response using vagal maneuvers for 9. ECGI obtained global accuracy to identify the involved atrial cavity of 91.7%, the mechanism of 89.6%, and the ablation target of 83.3%. In challenging cases, such as in patients with history of CA for AF (n = 27) and in patients without a final diagnosis of counterclockwise typical AFL (n=38) the diagnosis capacity of ECGI is consistent compared to the whole study population. The ECGI diagnostic capacity significantly outclassed the ECG one regarding the identification of the involved cavity (p&lt;0.001), the mechanism (p&lt;0.05), and the ablation target (p&lt;0.001). ECGI was able to prevent the totality of unnecessary transseptal punctures (n=7), representing 28% of the overall punctures.

Conclusions
(Figure B) – This novel non-invasive ECGI system that does not require CT/MRI thoracic imaging accurately characterizes complex atrial tachyarrhythmia and outclasses ECG, the current noninvasive diagnostic tool of reference.