Effects Of Fast Inward Current Inactivation On Propagation In A Two Dimensional Model Of Ventricular Myocardium

IN^ inactivation effects caused by subthreshold stimulation on longitudinal plane wavefront propagation characteristics were studied in a two-dimensional anisotropic sheet of tissue. The subthreshold stimulus was located either at the exit of a narrow isthmus, or half length constant (Ax/2) away from this structural complexity. Propagation characteristics changed dramatically depending on timing of the arrival of the plane wave to the stimulated site. IN^ inactivation produced conduction block when located at the exit of a narrow isthmus, and propagation delays (up to 7 msec). which were reduced as the stimulation point moved away from the narrow isthmus.