Ventricular tachycardia in a parallel processing environment

A one-dimensional ring of cardiac tissue was modeled on parallel processors in order to investigate double-wave reentry (DWR). The ring contained 1600 Beeler-Reuter cells, coupled by resistive gaps. The conditions required for DWR were studied using S1-S4 programmed stimulation. The results indicated the following: (1) A vulnerable window for DWR can be opened by S3, after wave collision is induced in the ring. Located between the points of collision and stimulation, the window is open for several ms following S3. (2) Acceleration of tachycardia beyond DWR can be accomplished by adding a third reentrant wave in the same circuit, with the S3-S4 pacing protocol and sufficient substrate values. The number of reentrant waves and the degree of acceleration are limited only by the ratio of action potential duration to excitable gap.