Figure 7

Electrophysiological characterization of human biopsies. (A) Temporally averaged AP for the 20-s transmembrane voltage recording of a point in a papillary muscle slice (left) and representative pseudo-color APD and activation time maps at a pacing frequency of 1 Hz for the same papillary muscle slice. The cross indicates the exact pixel for which the averaged AP is shown. (B) Same representations as in (A) but for a transmural biopsy slice. (C) Boxplots showing (left panel) APD in papillary muscle slices (p/n/N = 33/11/4) and transmural biopsy slices (p/n/N = 33/11/4), (central panel) normalized APD in response to a change in the pacing frequency from 1 to 2 Hz in papillary muscle slices (p/n/N = 27/9/4) and transmural biopsy slices (p/n/N = 15/5/4) and (right panel) 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). **p < 0.01; ***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 APD at baseline or normalized APD in tissue block slices versus transmural biopsy slices (in between two boxplots), according to Wilcoxon signed rank test (for paired samples) or Mann–Whitney U-test (for unpaired samples).