Calcium disorders mainly affect the QT interval on the ECG.
Hypocalcaemia (low serum calcium) causes a long QT interval. If you look closely at the long QT of hypocalcaemia you will notice that it lengthens the ST segment without greatly affecting the T wave.
It is interesting to note that because low calcium levels seem to affect the ST segment without affecting the T waves, very low calcium levels seem to have a lower risk of developing dysrhythmias than other causes of a prolonged QT interval.
- Hampton, J and Hampton, J (2019) - The ECG Made Easy, 9th edn, Elsevier
- Thaler, MS (2018) - The Only EKG Book You'll Ever Need, 9th edn, Lippincott Williams and Wilkins
- Grauer, K (2014) - ECG 2014 Pocket Brain, 6th edn, KG/EKG Press
- Houghton, AR and Gray, D (2014) - Making Sense of the ECG: A Hands-on Guide, 4th edn, Taylor and Francis
- Wagner, GS and Strauss, DG (2013) - Marriott's Practical Electrocardiography, 12th edn, LWW
- Goldberger, A (2006) - Clinical Electrocardiography: A Simplified Approach, 9th edn, Elsevier
- USMLEVideoLectures (2008) - Most Important ECG Findings in Major Diseases, (Accessed: 28/06/2019)
Groups of Signs
This ECG is from a dialysis patient who presented with diaphoresis and muscle cramps.
This ECG shows subtly peaked T waves and long ST segments causing a long QT interval. The cause was hyperkalemia (6.6) and hypocalcemia.
This ECG is from a woman in her 30s who presented with cramping following thyroid surgery.
This ECG shows prolonged QT due to long ST segment, no U waves, but also a prolonged QRS and PR. There was hypocalcemia, mild hyperkalemia and hypermagnesemia.
This ECG is from a patient with a history of diabetes who was found with a GCS of 4.
This ECG shows sinus rhythm with peaked T waves that were so narrow they were mistaken for separate QRS complexes. The cause was hyperkalemia due to acute renal failure.
This ECG is from a man in his 60s who presented with several weeks of diarrhoeal illness following overseas travel. He had a past medical history of ischaemic cardiomyopathy. His medications included warfarin, a beta-blocker, a PPI, an ACE inhibitor and diuretics.
Where did they come from?
These ECGs were collected from Free Open Access Medical Education (#FOAMed) blogs, with the permission of their authors. You can find out more about each ECG's source by clicking on it.
Why are they here?
This is an experiment in digital curation. The idea is to collect resources to increase awareness and accessibility. Over time, more ECGs in the collection will be tagged to make it easier to find them and reused in new interactive quizzes.
How can I use these ECGs?
You can use these ECGs for your own learning, teaching or research - as long as you abide by the terms of each ECG's copyright licence as stipulated by the original author.