ECG findings in hyperkalemia

  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.




Rare ECG abnormities due to hyperkalemia

  Nodal rhythm (junctional rhythm).

  ST-segment alternans.

  Left anterior fascicular block.

  Right bundle branch block.

  Left bundle branch block.

  Brugada-like electrocardiographic patterns.

  Spontaneous conversion of atrial fibrillation.

  Wide QRS tachycardia.

  Giant negative T waves (after treatment of hyperkalemia).




Clinical significance

  Sinus tachycardia in a chronic renal failure patient with hyperkalemia

      may be
erroneously diagnosed as ventricular tachycardia.

     
Hyperkalemia must be remembered in the differential diagnosis of wide-QRS tachycardia.



References

  Chou's Electrocardiography in Clinical Practice. Adult and Pediatric.

      5th ed. Philadelphia. WB Saunders. 2001.

  Circulation 1956;13(1):29-36.

  Cardiol Res 2017;8(2):77-80.

  Clin Cardiol 1981;4(1):43-46.

  Neth Heart J 2016;24(3):217-218.

  J Pediatr 1979;94(4):654-656.

  Medicine (Baltimore) 2018;97(15):e0442.

  Intern Med 2017;56(16):2243-2244.

  Neth Heart J 2003;11(6):268-271

  Medicina (Kaunas) 2013;49(3):148-153.

  J Electrocardiol 2007;40(1):53-59.

  Case Rep Cardiol 2017;2017:9464728.






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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