ECG findings

  P wave disappears or decreases in amplitude .

  PR interval increases .

  QRS complex widens.

  QT interval shortens.

  Sharp, pointed T wave with a narrow base.




The ECG findings of hyperkalemia have
low sensitivity and low spesificity.

Failure to observe these findings do not exclude the presence of hyperkalemia.




Clinical significance

  Sinus tachycardia in a chronic renal failure patient with hyperkalemia

      may be
erroneously diagnosed as ventricular tachycardia.





ECG 1a. ECG of a chronic renal failure patient immediately before hemodialysis. Serum potassium level is 7.1 mEq/L.

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ECG 1b. ECG of the same patient immediately after hemodialysis. Serum potassium level is 4.0 mEq/L.

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ECG 2a. The pre-dialysis ECG of another patient with serum potassium level of 6.6 mEq/L.

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ECG 2b. The ECG of the same patient after hemodialysis. The serum potassium level is 3.6 mEq/L.

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ECG 3a. The ECG above belongs to a patient who refused to undergo hemodialysis for 10 days.
Before hemodialysis, serum potassium level was 9 mEq/L while serum calcium level was 7.8 mg/dL.
ECG signs of both hyperkalemia and hypocalcemia are seen.

Dr. Muazzez Isik has donated the above ECG to our website.

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ECG 3b. The same patient's ECG after hemodialysis is seen above.
Postdialysis serum levels of potassium is 4.6 mEq/L while calcium is 10.5 mg/dL.

Dr. Muazzez Isik has donated the above ECG to our website.

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ECG 4a. The ECG above belongs to a patient with a serum potassium level of 8.9 mmol/L.
P waves are not seen, QRS complex is widened,
ST segment is absent while the T waves are peaked. (extremity leads).
The ECG is recorded at a paper speed of 50 mm/second, which has contributed to the wide appearance of the QRS complexes.

The above ECG has been donated by Dr. Peter Kukla to our website.

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ECG 4b. Precordial leads of the same patient is seen above.
The ECG is recorded at a paper speed of 50 mm/second, which has contributed to the wide appearance of the QRS complexes.

The above ECG has been donated by Dr. Peter Kukla to our website.

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ECG 5a. The ECG above belongs to an 85 years-old woman with mild aortic stenosis and a serum potassium level of 7 mmol/L.
There is right bundle branch block, The amplitude of the P wave in lead II is diminished.

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ECG 5b. The next day, her serum potassium level was decreased to 5.7 mmol/L and the above ECG was recorded.
Now the P wave amplitude in lead II is higher and the width of the QRS complex in anterior leads are lesser.

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ECG 6. The ECG above is from a 75 years-old woman with chronic renal insufficeny and heart failure (left ventricular
systolic dysfunction). At the time the above ECG was recorded, her serum potassium level was measured as 8.6 mmol/L.
She was also under Digoxin therapy.
P waves are not visible, QRS complexes are widened and the T waves in right precordial leads are relatively prominent.
The above ECG was recorded at a paper speed of 25mm/second.

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