ECG changes in uraemia

A prolonged QT interval is due to hypocalcaemia and tall T waves to hyperkalaemia and/or acidosis, which can be caused by uraemia. The main ECG change resulting from hypocalcaemia is a long QT interval due to prolongation of the ST segment.


Prolonged QT interval (Hypocalcaemia)

A prolonged Q-T interval refers to an abnormality seen on an electrocardiogram that reflects a disturbance in how your heart conducts electricity. [Source]

Long QT interval [Source]

    

The QT interval normally varies with heart rate - becoming shorter at faster rates. It is usually corrected using the cycle length (R-R interval) as shown opposite.
   

Normal QTc = 0.42 seconds

QTc calculation [Source]

Tall T waves (Hyperkalaemia)

The following changes may be seen in hyperkalaemia

• Small or absent P waves
• Atrial fibrillation
• Wide QRS
• Shortened or absent ST segment
• Wide, tall and tented T waves
• Ventricular fibrillation

ECG changed in hyperkalaemia. [Source]