[Computer simulation for localization and extensiveness of myocardial ischemia]

Features of genesis of the electrocardiosignal in conditions of the myocardial ischemia under changing localization and extensiveness of the ischemia foci, as well as an impact of this process on the repolarization parameters of the electrocardiosignal were investigated using a system for 3D simulation of the heart electrical activity. The model of the ventricles of the heart is a cellular automaton with the matrix about of 10(5) elements of the "Myocardium", "His", and "Purkinje" types and with prescribed rules of their interaction. In process of the study a developed earlier method of segmentation of the modeled ventricles was used. For estimating the contribution of the "ischemic" segments to the total signal of different leads of the electrocardiograms the previously suggested method of the partial curves was used. The ischemia foci were simulated by changing the characteristics of the transmembrane action potential in selected areas of the ventricles, such as the resting potential, transmembrane action potential amplitude, duration of the plateau phase, and the steepness of the final phase of rapid repolarization in accordance with literature data. Electrocardiosignals generated by the model were processed to obtain previously selected parameters, characterizing repolarization process. The influence of size and localization of the myocardial ischemia on the parameters obtained are examined, as well-as some hypotheses about their relation with an electrophysiological state of the heart muscle are discussed.