Electrocardiographic manifestations of serum hyperkalaemia relative to serum potassium level
| Serum potassium level | Expected ECG abnormality | |
|---|---|---|
| Mild hyperkalaemia 5.5–6.5 mmol/l | Tall, peaked T-waves with narrow base | |
| Moderate hyperkalaemia 6.5–8.0 mmol/l | Peaked T-waves | |
| Prolonged PR interval | ||
| Decreased amplitude of P-waves | ||
| Widening of QRS complex | ||
| Severe hyperkalaemia >8.0 mmol/l | Absence of P-wave | |
| Progressive widening of QRS complex | ||
| Eventual “sine-wave” pattern, VF, asystole | ||