Electrolyte Disorders

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Revision as of 20:29, 22 January 2010 by KGoldin (talk | contribs)
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Author(s) J.S.S.G. de Jong
Moderator T.T. Keller
some notes about authorship


Hypercalcemia, high blood calcium, speeds repolarization. Characteristics of hypercalcemia:

  • Mild: broad based tall peaking T waves
  • Severe: extremely wide QRS, low R wave, disappearance of p waves, tall peaking T waves.


ECG-characteristics of hypocalcemia, low blood calcium:

  • Narrowing of the QRS complex
  • Reduced PR interval
  • T wave flattening and inversion
  • Prolongation of the QT-interval
  • Prominent U-wave
  • Prolonged ST and ST-depression


ECG characteristics of hyperkalemia, high blood potassium:

  • Tall peaked T waves
  • Flattening p-waves. In extreme hyperkalemia p-waves may disappear altogether.
  • Prolonged depolarization leading to QRS widening (nonspecific intraventricular conduction defect) sometimes > 0.20 seconds

At concentrations > 7.5 mmol/L atrial and ventricular fibrillation can occur.


Hypokalemia, low blood potassium, results in:

  • ST depression and flattening of the T wave
  • Negative T waves
  • A U-wave may be visible