Application of a Theoretic T-Wave Model to Experimentally Induced T-Wave Abnormalities

Abstract

A series of experiments was performed to test the validity of a theoretic T-wave model. This model was based on the sequence of depolarization and on multiple action potentials taken in appropriate time phase. The previously introduced concept of the component gradient vector was extended so that this quantity included base-line and local gradient vectors. Component gradient vectors were defined as those vectors produced by a disparity in the configuration of coexisting action potentials. They were directed along the same axis as the depolarization vectors in the area where the component gradient existed. The magnitude of the component gradient vectors was determined by the degree to which the plateau durations and downstrokes of coexisting action potentials differed. Those component gradient vectors that arose from the normal disparity in configuration of ventricular action potentials were defined as base-line gradient vectors, while vectors that arose from a deviation from that state were defined as local gradient vectors. In the experiments reported, the predicted T-wave changes occurred. The maximal T vector tended to move along an imaginary line that was perpendicular to the line closing normal activation fronts in the area in which the local gradient was introduced. In a quantitative test of the model, FRP was measured and used as an indirect measure of the duration of the action potential plateau. The observed changes in T area were proportional to the magnitude of changes in functional refractory period (FRP). The results of these limited experiments indicate that the model should be useful in accounting for the configuration of T waves in states in which localized alterations of action potential configurations occur.