Modulation of repolarization by electrotonic interactions.

The expression of repolarization properties in different regions of the ventricle is a complex interaction between the spatial distribution of intrinsic properties of the cells and the spatial distribution of the coupling resistance among the cells of the cardiac syncytium. Our theoretical studies show that electrotonic modulation of repolarization among cells with intrinsically different repolarization properties can make the expressed properties of cells at a given location quite different from the intrinsic properties of these cells. These interactions are simulated both for a simple two cell system as well as for more complex geometries, showing that the spatial distribution of expressed repolarization properties is quite extensive, and, more specifically, is much more extensive than would be expected by passive electrotonic interactions.