Fig. 3.

Representative current clamp recordings of arrhythmia in LQT1A cardiomyocytes. (A) A cardiomyocyte without early afterdepolarization (EAD) in baseline (upper trace) and with (EAD) only observed at 1 mM [K+]Ex (lower trace). (B) Depicts a cardiomyocyte with EADs in baseline (upper trace) and EADs were prolonged at 1 mM [K+]Ex (lower trace). Arrows point to the beginning and end of the arrhythmic Phase 2. Scale bars: 40 mV in abscissa and 2 s in ordinate. Dashed lines (A and B) indicate 0 mV. Note that EADs were only found in LQT1A cardiomyocytes with more prolonged baseline APDs (see Fig. 2B for a comparison).