關於QT prolong的部分，我一開始也覺得很奇怪，但我回去check uptodate的內容，的確有提到這件事情
Electrocardiogram (ECG) changes are usually seen at concentrations of 5 to 10 mEq/L (6 to 12 mg/dL or 2.5 to 5 mmol/L). These changes include prolongation of the P-R interval, an increase in QRS duration, and an increase in Q-T interval.