FIGURE 2.

APD alternans in ionically homogeneous sheets without (A–D) and with (E–H) a structural barrier. (A–C) Spatial distribution of APD of even beat (APD_i; A) and odd beat (APD_i+1; B) and difference between successive beats (ΔAPD; C) in tissue without a structural barrier. (D) Voltage waveforms obtained from two different locations (marked “1” and “2”) in the sheet without a barrier. (E–H) Same as for A–D but in tissue with a structural barrier. A and E, B and F, and C and G are pairwise on the same color scale. Asterisks indicate stimulus site. BCL = 250 ms.