Hypercalcaemia causing marked shortening of the QT interval (260ms). Image originally featured in Kyuhyun (K.) Wang’s excellent Atlas of Electrocardiography.


  • Normal serum corrected calcium = 2.1 – 2.6 mmol/L
  • Mild hypercalcaemia =  2.7 – 2.9 mmol/L
  • Moderate hypercalcaemia = 3.0 – 3.4 mmol/L
  • Severe hypercalcaemia =  greater than 3.4 mmol/L

ECG Changes in Hypercalcaemia

Osborn waves caused by severe hypercalcaemia (4.1 mmol/L). Image reproduced from Otero & Lenihan (see references below)

Causes of Hypercalcaemia

  • Hyperparathyroidism (primary and tertiary)
  • Myeloma
  • Bony metastases
  • Paraneoplastic syndromes
  • Milk-alkali syndrome
  • Sarcoidosis
  • Excess vitamin D (e.g. iatrogenic)

A case of severe hypercalcaemia

This is the ECG of a 41-year old man with a parathyroid adenoma who presented to ED critically unwell with a serum calcium of 6.1 mmol/L. He suffered a VF arrest not long after this ECG was taken.

The ECG shows:

  • Bizarre-looking QRS complexes
  • Very short QT interval
  • J waves = notching of the terminal QRS, best seen in lead V1

Many thanks to Dr James Hayes, FACEM, for this fantastic ECG!

Related Topics

Further Reading

Author Credits


  • Kumar P, Clark M. Kumar & Clark’s Clinical Medicine (7th edition). London: Elsevier (2009).
  • Otero J, Lenihan DJ. The “normothermic” Osborn wave induced by severe hypercalcemia. Tex Heart Inst J. 2000;27(3):316-7. PMID: 11093425. Full text.
  • Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice (6th edition), Saunders 2008.
  • Wagner, GS. Marriott’s Practical Electrocardiography (11th edition), Lippincott Williams & Wilkins 2007.
  • Wang, K. Atlas of Electrocardiography (2011).
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  1. Stephen Smith says

    I’m sure you were not aware of it, but the hypercalcemia ECG is from Dr. K. Wang’s Atlas of Electrocardiography. I’m sure he would have given permission to use it. In any case, it would be good to give him credit. Where did you find it?

    • says

      Dear Steve,
      Thanks for pointing that out. I have amended the webpage accordingly.
      Also, thanks for introducing me to Dr. K. Wang’s Atlas of Electrocardiography… what a fantastic ECG resource!


  1. […] Milk-alkali syndrome, which is hypercalcemia, metabolic alkalosis, and renal insufficiency in the setting of ingestion of large amounts of calcium and bicarbonate, or betel nuts. The concept here is that acute renal failure usually causes acidosis; if you see alkalosis in the setting of acute renal failure, be suspicious of milk-alkali syndrome; in addition, other symptoms of hypercalcemia may be present as well such as confusion, abdominal pain; the mnemonic for hypercalcemia is “abdominal groans, pain in bones, stones and psychic overtones“; electrocardiogram may show short QT segment. […]