Hypocalcemia may produce a number of changes in the heart and in the electrocardiogram. Recognition is important since treating the hypocalcemia corrects the cardiac abnormality.


The classic ECG change is prolongation in the QT interval.


Less often changes may include:

(1) atrioventicular block, complete heart block or other conduction abnormality

(2) changes in the QRS and ST segments mimicking myocardial infarction

(3) changes in T wave amplitudes

(4) merging of the T and P waves

(5) ventricular tachycardia, ventricular fibrillation or other arrhythmias


Other cardiac manifestations with severe hypocalcemia:

(1) hypotension

(2) congestive heart failure

(3) hypokinetic cardiomyopathy


Clinical pattern:

(1) The ECG change occurs in a patient much younger than expected for the condition.

(2) The onset of the change is associated with hypocalcemia.

(3) The patient shows other manifestations of hypocalcemia (such as tetany).

(4) The condition reverses on calcium repletion.


The patient may have abnormalities in other electrolytes (potassium, magnesium) that may contribute to the cardiac abnormality.


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