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Figure 3 (Top panels) High T2- to T1-wave amplitude ratios during 24-h electrocardiographic (ECG) recordings in an unaffected subject (a), in three long-QT syndrome type 1 (LQT1) patients (b, c, and d), and in an LQT2 patient (e) (paper speed 25 mm/s). Baseline ECG recordings (leads V₁ to V₆, paper speed 50 mm/s) of the same patients are shown in the lower panels. Note that only the LQT2 patient exhibits bifid T waves in the baseline ECG recording.