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Figure 1 Electrocardiographic signals before, at times of maximal T2- to T1-wave amplitude ratios, and after the events of maximal T2- to T1-wave amplitude ratio in an unaffected subject (first panel), a long-QT syndrome type 1 (LQT1) patient (second panel), and an LQT2 patient (third panel). The two lower panels with a continuous electrocardiographic signal during a 20-s period show an episode of a prominent T2-wave in an LQT1 patient (modified lead V₅). Note that the T2-wave is present in 24 beats only, the arrows showing the first and the last beat with the T2-wave.