Computer Modelling of Cardiac Recovery Processes and Repolarization Sequences

A computer model has been developed which simulates both excitation and recovery processes within a block of heart muscle tissue. The model emphasizes the electro physiologic features of repolarization processes. It is comprised of artificial images of myocardial tissue consisting of several thousand elements and introduces phenomena that are omitted or seriously simplified in most of the existing computer models of cardiac electrophysiology. These phetiomeria include the abnormal shapes of action‐potential curves corresponding to premature excitation of cells that have not fully recovered, different durations of the repolarization phase in endoepicardial layers of tissue, and the tissue anisotropy of excitation transmission and electric resistivity. The model has been used in several experiments. Results of simulation studies are presented in the form of modelled 3‐lead electrocardiographic records. In spite of simple assumptions used at model construction, the results of simulation experiments reproduce natural phenomena. The experimental series include: simulation of regular activation sequences, models of ischemia and infarction, models of pnemature beats, simulation of effects due to fast sequential excitation, and simulation of reentry mechanisms with special reference to the initiation of ventricular fibrillation. The future development of more realistic models of cardiac recovery processes is also discussed.