Fig. 11.

Statistical analysis addressing the effect of chamber and time on the drug-induced action potential duration (APD) changes for each experimental group. A–D: group-wise means ± SE of the average APD₈₀ values in the right ventricle (RV) (blue) and the left ventricle (LV) (red) in sham (A), calyculin (B), KN93 (C), and H89 (D) groups. For each heart, the average RV and LV APD values were computed by averaging over all pixels in the respective regions of the APD maps. Black arrows indicate the time point from which the representative optical action potentials depicted in each panel were recorded. All data shown were obtained during pacing from an LV pacing site at a cycle length (CL) of 400 ms. For each group, a two-way ANOVA was performed to assess the role of chamber, time, and the chamber-time interaction in the distribution of mean conduction delay values. *P < 0.05 vs. baseline at the same chamber (Tukey-Kramer post hoc test).