Complexity analysis of electrical activity during endocardial and epicardial biventricular mapping of ventricular fibrillation

Vasanth Ravikumar; Xiangzhen Kong; Nick Y Tan; George Christopolous; Thomas P Ladas; Zhi Jiang; Jason A Tri; Alan M Sugrue; Samuel J Asirvatham; Christopher V DeSimone; Elena G Tolkacheva

doi:10.1007/s10840-023-01606-9

Complexity analysis of electrical activity during endocardial and epicardial biventricular mapping of ventricular fibrillation

J Interv Card Electrophysiol. 2023 Jul 11. doi: 10.1007/s10840-023-01606-9. Online ahead of print.

Authors

Affiliations

¹ Department of Electrical Engineering, University of Minnesota, Minneapolis, USA.
² Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.
³ Department of Biomedical Engineering, University of Minnesota, 312 Church St SE, Minneapolis, MN, 55455, USA. talkacal@umn.edu.
⁴ Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, USA. talkacal@umn.edu.
⁵ Institute for Engineering in Medicine, University of Minnesota, Minneapolis, MN, USA. talkacal@umn.edu.

PMID: 37434040
DOI: 10.1007/s10840-023-01606-9

Abstract

Background: Ventricular fibrillation (VF) is a lethal cardiac arrhythmia that is a significant cause of sudden cardiac death. Comprehensive studies of spatiotemporal characteristics of VF in situ are difficult to perform with current mapping systems and catheter technology.

Objective: The goal of this study was to develop a computational approach to characterize VF using a commercially available technology in a large animal model. Prior data suggests that characterization of spatiotemporal organization of electrical activity during VF can be used to provide better mechanistic understanding and potential ablation targets to modify VF and its substrate. We therefore evaluated intracardiac electrograms during biventricular mapping of the endocardium (ENDO) and epicardium (EPI) in acute canine studies.

Methods: To develop thresholds for organized and disorganized activity, a linear discriminant analysis (LDA)-based approach was performed to the known organized and disorganized activities recorded in ex vivo Langendorff-perfused rat and rabbit hearts using optical mapping experiments. Several frequency- and time-domain approaches were used as individual and paired features to identify the optimal thresholds for the LDA approach. Subsequently, VF was sequentially mapped in 4 canine hearts, using the CARTO mapping system with a multipolar mapping catheter in the ENDO left and right ventricles and EPI to capture the progression of VF at 3 discrete post-induction time intervals: VF period 1 (just after induction of VF to 15 min), VF period 2 (15 to 30 min), and VF period 3 (30 to 45 min). The developed LDA model, cycle lengths (CL), and regularity indices (RI) were applied to all recorded intracardiac electrograms to quantify the spatiotemporal organization of VF in canine hearts.

Results: We demonstrated the presence of organized activity in the EPI as VF progresses, in contrary to the ENDO, where the activity stays disorganized. The shortest CL always occurred in the ENDO, especially the RV, indicating a faster VF activity. The highest RI was found in the EPI in all hearts for all VF stages, indicating spatiotemporal consistency of RR intervals.

Conclusion: We identified electrical organization and spatiotemporal differences throughout VF in canine hearts from induction to asystole. Notably, the RV ENDO is characterized by a high level of disorganization and faster VF frequency. In contrast, EPI has a high spatiotemporal organization of VF and consistently long RR intervals.

Keywords: Electro-anatomical mapping; Linear discriminant analysis; Mutual information; Spatiotemporal organization; Ventricular fibrillation.