The genesis of injury potentials: the role of recording electrodes at different locations.

The objective of the present study was to elucidate the mechanisms underlying the so-called injury potentials, including the origin of monophasic action potentials and the role of recording electrodes. Two-dimensional computer simulation was performed for cardiac tissue containing an inactivated region due to high extracellular K concentration. Myocardial activation was reproduced using a membrane model. The bidomain model was utilized for the calculation of intra-and extracellular potentials. A bipolar lead from electrodes at injured and intact regions showed a monophasic curve corresponding to the transmembrane potential of the fiber under the electrode of the intact region. Unipolar leads from injured and intact regions showed monophasic and biphasic curves, respectively. Lowering the extracellular conductivity was associated with an increase in the wave amplitude. The injured region of myocardium was associated with monophasic potential variations. A bipolar lead with electrodes at injured and intact regions reflected the activity of the intact region.