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Figure 4 (A) Representative electrocardiogram tracings from an experiment with sertindole-induced torsades de pointes arrhythmia followed by an intervention using 2 consecutive doses of the IK,ATP activator levcromakalim (levcro.). Two electrocardiogram leads, left ventricular (LV) and right ventricular (RV) monophasic action potential (MAP) recordings in each panel. RR below and QT time above lead II. Monophasic action potential durations (MAPDs) are below each signal. Paper speed: 1 cm/s. (B) Poincaré plots from the 4 panels in (A). Note the absence of shortening of repolarization duration despite a smaller Poincaré plot after 3 µg/kg levcro.