Role of early afterdepolarizations on ectopic activity in ventricular tissue. A computer modeling study

The authors have used a computer model of the ventricular action potential to study conditions in which EADs developed in an area of ventricular myocardium can propagate to other areas, generating ectopic activity. They simulate the interactions between two areas of myocardium; one of them can develop EADs while the other is kept under normal conditions. Both zones are coupled through an area of inexcitable tissue, simulated by a resistance R. The results show that for values of R in the range from 38 Ωcm² to 50 Ω cm², the EAD generated in the abnormal zone is propagated to the normal area as an ectopic beat. For R values out of this range, when the action potential propagates, the EAD only inducer lengthening of action potential in some cells of the normal zone and ectopic activity on normal cells is not observed