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Fiber orientation and cell-cell coupling influence ventricular fibrillation dynamics
Journal of Cardiovascular Electrophysiology
|August 2, 2003
Summary
Cell coupling and fiber orientation directly impact ventricular fibrillation (VF) dynamics. Analysis revealed elliptical gradients aligned with fiber direction, showing cell-cell coupling
Area of Science:
- Cardiovascular Physiology
- Computational Biology
- Biophysics
Background:
- Ventricular fibrillation (VF) structure is influenced by regional action potential differences, restitution kinetics, and fiber anisotropy.
- Understanding VF spatial organization is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the spatial organization of ventricular fibrillation (VF).
- To measure cross-correlation (CC) and mutual information (MI) of membrane potential (Vm) oscillations to understand VF dynamics.
Main Methods:
- Rabbit hearts were perfused and stained, with VF induced by burst pacing.
- Optical recordings of Vm oscillations were captured using photodiode arrays and CCD cameras.
- Calculated maximum CC (CCmax) and MI (MImax) between recording sites to map spatial organization.
Main Results:
- CCmax and MImax decreased monotonically with increasing distance between pixels.
- Maps of CCmax and MImax revealed elliptical gradients closely aligned with cardiac fiber orientation.
- No discrete regions of high CC or MI were observed.
Conclusions:
- Anisotropy of cardiac fiber orientation directly influences VF dynamics.
- Cell-cell coupling plays a direct role in the spatial organization and dynamics of VF.
- CC and MI analysis offer new insights into fibrillation mechanisms.