CONTROL OF ROTATING WAVES IN CARDIAC-MUSCLE - ANALYSIS OF THE EFFECT OF AN ELECTRIC-FIELD

The effect of an electric field on rotating waves in cardiac muscle is considered from a theoretical point of view. A model of excitation pr opagation taking into account the cellular structure of the heart is p resented and studied. The application of a direct current electric fie ld along the cardiac tissue is known to induce changes in membrane pot ential which decay exponentially with distance. Investigation of the m odel shows that the electric field induces a gradient of potential ins ide a cell which does not decay with distance, and results in modifica tion of excitation propagation which extends a considerable distance f rom the electrodes. In two dimensions, it induces a drift of rotating waves. The effect of the electric field on propagation velocity and on rotating waves cannot be obtained in any arbitrary models of cardiac muscle. For an electric field of about 1 V cm(-1) and junctional resis tances of about 20 M Omega, the change in velocity of propagation can be up to several percent, resulting in a drift velocity of rotating wa ves of the order of 1 cm s(-1). To test these predictions, experiments with cardiac preparations are proposed.