Simulations were designed to identify the minimum number of cardiac cells that sustained propagation. Cells were connected as a loop with elevated junction resistances. The decrease in the spatial extent of the action potential associated with increasing the junction resistances to 1200 MΩ allowed propagation to be sustained in loops as small as 11 cells. Membrane kinetics spontaneous adjusted to the premature stimulation intrinsic to reentrant propagation, and thereby allowed propagation to be sustained with further decrease in the loop size. The simulations used the DiFrancesco-Noble membrane model. A minimum of 9 cells sustained propagation when the junction resistances were 1000 MΩ.