Hypocalcaemia

ECG changes in Hypocalcaemia

Hypocalcaemia Overview

• Normal serum corrected calcium = 2.2 – 2.6 mmol/L.
• Mild-moderate hypocalcaemia = 1.9 – 2.2 mmol/L.
• Severe hypocalcaemia = < 1.9 mmol/L.

Causes of Hypocalcaemia

• Hypoparathyroidism
• Vitamin D deficiency
• Acute pancreatitis
• Hyperphosphataemia
• Hypomagnesaemia
• Diuretics (frusemide)
• Pseudohypoparathyroidism
• Congenital disorders (e.g. DiGeorge syndrome)
• Critical illness (e.g. sepsis)
• Factitious (e.g. EDTA blood tube contamination)

Symptoms of Hypocalcaemia

• Neuromuscular excitability
• Carpopedal spasm
• Tetany
• Chvostek sign
• Trousseau sign
• Seizures

ECG Examples

Example 1

Hypocalcaemia:

• QTc 500ms in a patient with hypoparathyroidism (post thyroidectomy) and serum corrected calcium of 1.40 mmol/L
• Reproduced from Nijjer et al. (2010)

Example 2

Hypocalcaemia:

• QT prolongation in a patient with DiGeorge’s syndrome and serum calcium of 1.32 mmol/L
• Reproduced from Kar et al. (2005)

Example 3

• Hypocalcaemia causing a long QTc (510ms)

Related Topics

• Hyperkalemia
• Hypokalemia
• Hypercalcemia
• Measurement of the QT interval
• Hypomagnesemia

References

• Nijjer S, Ghosh AK, Dubrey SW. Hypocalcaemia, long QT interval and atrial arrhythmias. BMJ Case Reports 2010
• Kar PS, Ogoe B, Poole R, Meeking D. Di-George syndrome presenting with hypocalcaemia in adulthood: two case reports and a review. J Clin Pathol. 2005 Jun;58(6):655-7

Advanced Reading

Online

• Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery
• Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course: Become an ECG expert. Medmastery
• Kühn P, Houghton A. ECG Mastery: Black Belt Workshop. Advanced ECG interpretation. Medmastery
• Rawshani A. Clinical ECG Interpretation ECG Waves
• Smith SW. Dr Smith’s ECG blog.

Textbooks

• Zimmerman FH. ECG Core Curriculum. 2023
• Mattu A, Berberian J, Brady WJ. Emergency ECGs: Case-Based Review and Interpretations, 2022
• Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
• Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
• Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
• Hampton J, Adlam D. The ECG Made Practical 7e, 2019
• Kühn P, Lang C, Wiesbauer F. ECG Mastery: The Simplest Way to Learn the ECG. 2015
• Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
• Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
• Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004

LITFL Further Reading

• ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
• ECG A to Z by diagnosis – ECG interpretation in clinical context
• ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
• 100 ECG Quiz – Self-assessment tool for examination practice
• ECG Reference SITES and BOOKS – the best of the rest