Figure 7. Representative examples of the effects of pacing rate and of a pause on WT or mutant peak I_Nas.

APs were recorded from a ‘subepicardial’ cell successively coupled to HEK cells transfected with WT (top), Y1795C (middle) or A1330P (bottom) channels. A normal (WT) response is shown in the top panels, while APs in LQT syndrome are prolonged compared to normal (middle and bottom). At 2 Hz, after the pause, the extent of AP prolongation is exaggerated and heterogeneous. Note the corresponding I_Nas.