Fig. 1

Electrocardiogram of the patient. A 24 h dynamic electrocardiogram (Holter) of the patient (25 mm/s, 10 mm/mV). Average heart rate 64 bpm (range 47-109 bpm), corrected QT (QTc) interval of 470 ms (maximum 595 ms). Typical biphasic and notched T wave was presented and marked by red arrow. B Emergent electrocardiogram during an attack on the second evening after admission (25 mm/s, 10 mm/mV). Average heart rate 66 bpm, QTc interval of 470 ms. Frequent ventricular premature beats were also recorded