BSCC Physiology 015
ECG waves and hyperkalaemia
QRS = 0.08 – 0.1 sec
QT = 0.4 – 0.43 sec
ST = 0.32 secChanges with Hyperkalaemia and Hypokalaemia:Hyperkalaemia:
Initially peak T waves are present (T waves you would not want to sit on)
As the hyperkalaemia progresses there is flattening of the P wave and PR prolongation with a peaked T wave.
At higher levels no atrial activity is seen and QRS widening develops
Severe hyperkalaemia causes idoventicular rhythms, sine wave and VF arrest.
Initially the PR interval is prolonged but the QRS remains unchanged and a U wave develops
As the hypokalaemia progresses there is still PR prolongation but ST depression, T wave inversions and a more prominent U wave can develop