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High-Resolution Endocardial and Epicardial Optical Mapping in a Sheep Model of Stretch-Induced Atrial Fibrillation
Published on: July 29, 2011
15.3K
Optical Mapping of Ventricular Fibrillation Dynamics.
1F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
Advances in Experimental Medicine and Biology
|August 5, 2015
Summary
Ventricular fibrillation (VF) dynamics vary by species, with rabbit hearts showing 2D patterns and pig hearts exhibiting 3D patterns. Findings suggest action potential duration restitution and spatial dispersion may not be essential causes of VF dynamics.
Area of Science:
- Cardiovascular Electrophysiology
- Cardiac Arrhythmia Research
- Computational Biology
Background:
- Limited understanding of human ventricular fibrillation (VF) dynamics.
- Reliance on animal models and simulations for VF mechanism hypotheses.
- Challenges in quantifying complex VF spatial-temporal patterns.
Purpose of the Study:
- To compare quantitative analyses of VF patterns across four animal models.
- To investigate the role of action potential duration restitution and spatial dispersion in VF.
- To explore species-specific differences in VF dynamics.
Main Methods:
- Utilized optical mapping and video imaging for high-resolution transmembrane recordings.
- Derived phase maps to identify phase singularities as a measure of VF complexity.
- Analyzed electrophysiological quantities and spatial dispersion during VF in rabbit and pig models.
Main Results:
- Action potential duration restitution slope was negative during VF in all models.
- No significant difference in spatial dispersion of electrophysiological parameters during early VF compared to pre-VF pacing.
- VF exhibited 2D dynamics in small rabbit hearts and 3D dynamics in large pig hearts.
Conclusions:
- Action potential duration restitution and spatial dispersion may not be essential drivers of VF dynamics.
- Heart size influences VF dimensionality, with larger hearts supporting more complex, self-sustaining dynamics.
- Findings provide physiological insights into species-specific VF mechanisms.
