Hypokalemia produces characteristic electrocardiographic changes that reflect the influence of low potassium levels on the cardiac action potential. It is defined as a serum potassium level < 3.5 mEq/L.

Electrocardiographic Findings

  • Increased P-wave amplitude
  • Increased QRS amplitude and duration
  • Decreased T-wave amplitude, associated with increased U-wave amplitude and ST-segment depression

ECG in Hypokalemia

Electrocardiogram showing hypokalemia with U waves

Hypokalemia. Prominent U waves in a patient with hypokalemia.

References

  1. Scheffer MK, De Marchi MFN, de Alencar Neto JN, Felicioni SP. Eletrocardiograma de A a Z. São Paulo: Manole, 2024.