Action Potential and Conduction Velocity Restitution in Cardiac Tissue
Abstract
In cardiac tissue, the combination of action potential restitution and conduction velocity restitution determines the pacing rate at which action potential duration changes from a constant to a long-short alternating pattern known as alternans. In a spatially extended system, alternans can be either concordant, where all parts of the tissue oscillate in phase, or discordant, where two parts of the tissue oscillate out of phase. Much of the current mathematical theory on this instability is based on two assumptions: that both the action potential restitution curve and the conduction velocity restitution curve are unique. However, several different pacing protocols are currently used to determine restitution curves, with each protocol yielding a different curve. We have developed a new pacing protocol which allows visualization of multiple aspects of cardiac dynamics simultaneously. This "restitution portrait" establishes the relationship between currently measured restitution curves and can be used to determine the underlying cause of the transitions to concordant or discordant alternans.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MAR.L9008D