Ectopic activity generated by early after-depolarizations in ventricular tissue: a computer simulation study

A computer model of two partially coupled ventricular fibers was used to study conditions in which EADs generated in a zone of ventricular myocardium may propagate to other zones, inducing ectopic activity. The model consists of two one-dimensional arrays of cells coupled by a resistance R. EADs are induced in one of the segments while the other is kept under normal conditions. For values of R in the range from 38 /spl Omega/ cm/sup 2/ to 50 /spl Omega/ cm/sup 2/, the second EAD that appears in the EAD segment propagates to the normal segment as an ectopic beat. For R values out of this range the EAD only increases the action potential duration in some cells of the normal zone and ectopic activity in the normal cells is not observed.