Simulation of Propagation in a Realistic-geometry Computer Heart Model with Parallel Processing

The simulation of the propagation of electrical activity in a realistic-geometry computer model of the ventricles of the human heart using the governing reaction-diffusion equation is described. Each model point is represented by the phase 1 LuoRudy membrane model, appropriately modified to represent human action potentials. A separate longer-duration action potential waveform was used for the M cells found in the ventricular mid-wall. Cardiac fiber rotation across the ventricular wall was implemented via an analytic equation, resulting in a spatially-varying anisotropic conductivity tensor and consequently anisotropic propagation. Since the model comprises approximately 12 million points, parallel processing was used to cut down on simulation time. The model generated acceptablynormal electrocardiograms, vectorcardiograms and body surface potential maps on the surface of a numerical human torso model. Interestingly, it was found that the intrinsic difference in action potential duration between M cells and other myocardial cells was greatly diminished due to electrotonic coupling.