Potassium: ECG changes
Advanced, Organ-Based and Clinical Sciences
Earliest change →ST-segment depression, T-wave flattening and inversion, PR interval prolongation along with increase in P-wave amplitude.
When Serum K < 2 meq/L → U and T waves fuse (giant U waves mask smaller preceding T wave)
Pseudo-prolonged QT interval → Actually QU interval in absence of T wave.
Severe hyperkalemia → Tachyarrhythmia (ventricular tachycardia and fibrillation)
→ Rare occasions AV block.
→ Can lead to Torsade’s de points
Hyperkalemia (see image 3)
Early ECG changes → Peaked T waves
→ Short PR interval
Later changes → Loss of P wave → followed widening of QRS complex → “sine wave” morphology.