ECG changes in hypokalaemia

Last edited 02/2018 and last reviewed 07/2021

Hypokalaemia can cause:

  • flattened T waves
  • ST segment depression
  • prolonged QT interval
  • tall U waves
  • atrial arrythmias
  • ventricular tachycardia or ventricular fibrillation and torsade de pointes.


  • ECG changes seen in hypokalaemia is not reliable since some severe hypokalaemic patients may not exhibit these changes (1)

Click here for an example ECG and further information