THE SENSITIVITY OF THE PASSIVE BIDOMAIN EQUATION TO VARIATIONS IN SIX CONDUCTIVITY VALUES

摘要

Previous work has shown that variations in cardiac conductivityvalues have significant effects on the resulting epicardialpotential distributions arising from subendocardialischaemia. This work carries on from a previous study inthis area by allowing for variation in (the more physiologicallyrealistic) six, rather than four, conductivity values.This is achieved by relaxing the usual assumption that thecardiac conductivity values in both normal directions, onenormal to the fibres within the sheet and the other normal tothe sheet, are equal. An extended non–dimensional formulationis derived for the passive bidomain equation, leadingto a normal direction dimensionless conductivity ratio,in addition to the previously found ratios in the transverseand longitudinal directions. Two six–conductivity datasetsare used to set up a parameter space for the above ratios,from which epicardial potential distributions are derivedand compared. Results from this study appear to supportthe conclusions of the previous four–conductivity study;that is, differences in the epicardial potential distributionsare best explained by variations in the ratio of the intracellularlongitudinal conductivity to the intracellular transverseconductivity.