COMPARATIVE SIMULATION OF EXCITATION AND BODY-SURFACE ELECTROCARDIOGRAM WITH ISOTROPIC AND ANISOTROPIC COMPUTER HEART MODELS

Comparative simulations between isotropic and anisotropic computer hea rt models were conducted to study the effects of myocardial anisotropy on the excitation process of the heart and on body surface electrocar diogram, The isotropic heart model includes atria, ventricles, and a s pecial conduction system, and is electrophysiologically specified by p arameters relative to action potential, conduction velocity, automatic ity, and pacing, The anisotropic heart model was created by incorporat ing rotating fiber directions into the ventricles of the isotropic hea rt model, The orientation of the myocardial fibers in the ventricles o f the model was gradually rotated counterclockwise from the epicardial layer to the endocardial layer for a total rotation of 90 degrees. Th e anisotropy of conduction velocity and intracellular electric conduct ivity was included in the simulation, Comparative simulations of the n ormal heart, LBBB, and RBBB showed no significant differences between the two models in the excitation processes of the whole heart or in th e body surface electrocardiograms. However, it was easier to induce ve ntricular fibrillation in the anisotropic model than in the isotropic model, The comparative simulation is useful for investigating the effe cts of myocardial anisotropy at the whole heart level and for evaluati ng limitations of the isotropic heart model.