Figure 1

Idealised arrangement of cardiac tissue with regional differences in APD restitution. (a) Two-dimensional tissue sheet, with regions R1 and R2 outlined in red and blue respectively, and stimulus electrode at the bottom. (b) Cartoon of APD restitution of regions R1 (red) and R2 (blue), showing APDs in each region resulting from stimulus at long and short DI. (c) Cartoon of action potentials elicited in R1 and R2 with S1 S2 S3 stimulus protocol.