Figure 6

Characterization of the response to an increase in pacing frequency and to β-adrenergic stimulation in pig slices. Left panel: boxplots showing APD in tissue block slices (p/n/N = 36/12/4) and transmural biopsy slices from the same pigs (p/n/N = 36/12/4). Central panel: boxplots showing normalized APD in response to a change in the pacing frequency from 1 to 2 Hz in tissue block slices (p/n/N = 30/10/4) and transmural biopsy slices (p/n/N = 27/9/4) from the same pigs. Right panel: boxplots showing normalized APD in response to 100 nM isoproterenol in tissue block slices (p/n/N = 33/11/4) and transmural biopsy slices (p/n/N = 33/11/4) from the same pigs. ***p < 0.001 and n.s. non-statistically significant differences, either in the comparison of APD for 2 Hz versus 1 Hz or isoproterenol versus baseline in the same tissue slices (shown on top of a boxplot) or in the comparison of normalized APD in tissue block slices versus transmural biopsy slices (in between two boxplots) according to Wilcoxon signed rank test.