The ventricular tachycardias (VT) that originate in the 5-day epicardial border zone (EBZ) of the healing canine infarcted heart are due to reentrant excitation. We previously showed that the heterogeneities in I_Na and I_CaL channels of the center and outer pathway cells result in a homogenization of the refractory period which in turn stabilizes VTs for about 10 beats. To understand how the heterogeneities in transverse gap junctional conductance (GJ) remodeling reported experimentally contribute to the stability of VT, we studied the dynamics of reentry in 2D computer models of the EBZ. Results: In a computer model with homogeneous ionic channel properties (IZ model). These simulations show that, in the absence of heterogeneities in ionic channel properties, reentrant waves tend to drift to localized regions of uncoupling and stabilize there. With a more realistic representation of the heterogeneous EBZ including cellular models for both the center (IZc) and outer (IZo) pathway cells. These simulations show that neither a region of uniform uncoupling nor a step transition between two regions with different side-to-side (transverse) cell coupling stabilizes reentry in this substrate. However, an area of localized uncoupling did stabilize reentry in such a model. Conclusions: We propose that in addition to the heterogeneities in I_Na and I_CaL channel properties, heterogeneities in Gj in the EBZ causing regions of localized uncoupling stabilize VT in the EBZ. This is consistent with previous experimental in situ activation maps of the EBZ show that the lines of block form in regions of slow transverse propagation.