Fig. 3.

Electrophysiological properties of Langendorff-perfused hearts from Scn5a+/− and WT mice under isoprenaline challenge. A: conduction velocity dynamics mirrored those seen in tissue slice preparations, with paradoxical responses to isoprenaline challenge in the heterozygous mouse hearts. B: the mean increase in delay (MID) of Scn5a+/− hearts was markedly greater than those of WT animals. C: unlike tissue slices, only marginal differences in effective refractory period (ERP) were observed in whole heart preparations. Asterisks indicate statistical significances from comparisons between Scn5a+/− and WT (**P < 0.01, ***P < 0.001).