Case Study: Hyperkalemia and ECG Changes

Case Presentation

A 70-year-old male presented to the ER with giddiness & presyncope for the past two hours. He was also having difficulty in breathing. No other history was known, except that he was diabetic.

The first ECG:
first ecg - V

The second ECG after a few minutes:
second ecg - V

ECG showed a lack of P waves, suggesting junctional rhythm, slight widening of QRS and tall T waves with a narrow base (especially in the first ECG), producing an “Eiffel Tower” appearance.

The patient was referred for pacing, considering sick sinus syndrome. At first impression, due to bradycardia, he seems to be in need of temporary pacing.

Further blood investigations revealed electrolytes K: 7.9 and creatinine of 3.0. Immediately, K correction was started. After K correction, the ventricular rate increased.

ECG After K Correction:
ecg after k correction - V


In any patient presenting with symptomatic bradyarrhythmias, always rule out reversible causes first. Correction and treatment of these reversible causes may avoid the need for permanent pacing. Hyperkalemia is not an uncommon cause of symptomatic bradyarrhythmias and is [s2If !is_user_logged_in()]…

[/s2If][s2If is_user_logged_in()] more common with long-standing diabetes with end organ damage, like nephropathy.

Whenever you see a bradycardia with loss of P waves or minuscule P waves and TALL peaking T waves with narrow base and widening of QRS, always seek whether patient is having hyperkalemia. In all cases, except one condition, “Hyperkalemic periodic paralysis,” there will be some predisposing condition for hyperkalemia.

In this patient, it was probably hyperkalemia caused by ACETAZOLAMIDE , which was given for an eye problem. It would have caused acidosis, leading to hyperkalemia. Plus, he had long-standing diabetes with nephropathy, leading to renal dysfunction.

Following are the ECG changes in hyperkalemia (in sequence), and they fairly correlate with Serum K+ levels.

  1. Tall peaked T waves with narrow base (Eiffel Tower appearance)
  2. Loss of P waves and PR interval prolongation
  3. Widening of QRS – In spite of no P Waves seen on the ECG, it is still sinus rhythm; there is an apparent loss of P Wave voltage due to hyperkalemia
  4. Sino-ventricular rhythm and sine wave pattern
  5. Ventricular arrhythmias

In this patient, the sinus rhythm was restored after the correction of hyperkalemia, and permanent pacing was avoided. It was hyperkalemia causing the ECG changes, and it corrected with serum K correction. It was NOT Sick sinus syndrome.

Learning Points/Take Home Messages

  • Always look for reversible causes in any patient presenting with bradyarrhythmias, electrolyte disturbances especially. Hyperkalemia is not an uncommon etiology. It can be suspected on ECG before the Serum K+ blood levels are known.
  • Tall “T” waves with a narrow base (Eiffel Tower appearance), absence or miniscule “P” waves, prolonged PR interval, widening of QRS, and sine wave pattern are the ECG changes which raise the suspicion of hyperkalemia in any patient.

Hyperkalemia, hyperacute ischemia and normal variant are the three main causes of Tall T waves in ECGs. The “T” waves’ morphology is different in these conditions, as follows:

  1. Hyperkalemia: Symmetric, narrow-based, pointed, tenting of T waves, shortened QT interval
  2. Hyperacute Ischemia: Symmetric, broad based, not tented or pointed, QT interval prolonged
  3. Normal Variant: Asymmetric and not narrow base

About The Author

Dr. Vachharajani is an experienced practicing family physician in Ahmedabad, Gujarat, with a special interest in obesity and lifestyle-related disorders. With a genuine passion and enthusiasm for healthcare information technology (HIT), he has championed the cause of using HIT in day-to-day clinical practice. In addition to his, MBBS, he holds a post-graduate certificate in environmental and occupational health (PGDMCH).


Contributing Author

SankhlaDr. Vinit Sankhla, MD DM Cardiology (CMC Vellore), Fellow of European Society of Cardiology (FESC-International), Fellow of Indian Society of Electrocardiology (FISE) and Consultant Interventional Cardiologist.




Log in or register for free to continue reading
Register Now For Free Already Registered? Log In
This entry was posted in Case Studies and tagged . Volume: .


  1. Rudresh Scharma
    Posted Sep 2014 at 12:56 pm | Permalink

    Good, informative and practical

  2. Thomas Kuruvilla
    Posted Jan 2015 at 7:36 pm | Permalink

    Thank you! that was informative!

Post a Comment

You must be logged in to post a comment.