Hypercalcaemia

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

Definitions

• 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

• The main ECG abnormality seen with hypercalcaemia is shortening of the QT interval
• In severe hypercalcaemia, Osborn waves (J waves) may be seen
• Ventricular irritability and VF arrest has been reported with extreme 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

• Hypocalcaemia
• Osborn waves
• Measurement of the QT interval

Further Reading

• ECG BASICS – Waves, Intervals, Segments and Clinical Interpretation
• ECG CLINICAL CASES – Your favourite ECG’s placed in clinical context with a challenging Q&A approach
• ECG and Cardiology Eponymous Syndromes – Cheats guide to eponymous emancipation
• ECG Reference Sites on the WEB – the best of the rest

Author Credits

References

• 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).