Related Experiment Video
Updated: Jul 23, 2025
High-Resolution Endocardial and Epicardial Optical Mapping in a Sheep Model of Stretch-Induced Atrial Fibrillation
Published on: July 29, 2011
Complexity analysis of electrical activity during endocardial and epicardial biventricular mapping of ventricular
Vasanth Ravikumar1, Xiangzhen Kong1, Nick Y Tan2
1Department of Electrical Engineering, University of Minnesota, Minneapolis, USA.
Insights
Ventricular fibrillation (VF) exhibits distinct spatial and temporal electrical organization. The endocardium shows disorganized, rapid activity, while the epicardium displays organized, slower electrical patterns during VF progression.
Area of Science:
- Cardiac Electrophysiology
- Computational Cardiology
- Arrhythmia Mechanisms
Background:
- Ventricular fibrillation (VF) is a major cause of sudden cardiac death.
- Current mapping technologies limit comprehensive in situ VF spatiotemporal analysis.
Purpose of the Study:
- Develop a computational method to characterize VF spatiotemporal organization using commercial technology.
- Investigate VF substrate and potential ablation targets through detailed electrical mapping.
- Evaluate intracardiac electrograms during biventricular mapping in a canine model.
Main Methods:
- Developed a linear discriminant analysis (LDA) model using optical mapping data to differentiate organized and disorganized electrical activity.
- Performed biventricular endocardial (ENDO) and epicardial (EPI) mapping in 4 canine hearts during VF.
- Applied LDA, cycle length (CL), and regularity index (RI) to intracardiac electrograms at three VF progression intervals.
Main Results:
- Organized electrical activity was observed in the epicardium (EPI) as VF progressed, contrasting with the endocardium (ENDO).
- The endocardium, particularly the right ventricle (RV), exhibited shorter cycle lengths (CL), indicating faster VF activity.
- The epicardium showed higher regularity indices (RI) across all VF stages, suggesting consistent spatiotemporal electrical patterns.
Conclusions:
- Identified distinct electrical organization and spatiotemporal differences in canine hearts during VF progression.
- The RV endocardium is characterized by high disorganization and faster VF frequency.
- The epicardium demonstrates high spatiotemporal organization and consistent, longer RR intervals during VF.
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.
More Related Videos
10:17Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
06:57Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction
Published on: January 31, 2019
Related Concept Videos
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
01:28Electrocardiogram Fundamentals
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin...
01:19Electrophysiology of Normal Cardiac Rhythm
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
01:29Dysrhythmias III: Characteristics of Dysrhythmias
01:29Electrocardiogram
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and...