Fig. 4.

Drug-induced TdP-like EFP waveforms in CTSs under 1-Hz pacing. a Overlaid EFP waveforms at each E-4031 dosage under 1-Hz pacing. FPD prolongation is observed. b Relative change in FPD after E-4031 treatment under 1-Hz pacing (±s.d., n = 4). c Representative TdP-like waveforms after E-4031 treatment (1 μM) under 1-Hz pacing. The white arrowhead shows transient pacing failure that is not followed by electrical excitation of the CTS. The orange arrowhead shows pacing success followed by electrical excitation of CTS. The first pacing failure resulted in short-long-short sequence-like waveforms