Melanie Baimel’s Best Case Ever on Post-Arrest Hyperkalemia on EM Cases

Post arrest patients can sometimes be challenging. We need to think of a variety of underlying causes of the arrest, antiarrhythmics, possible cath lab activation, targeted temperature management, sedation and more. To add to this, many post arrest patients do not have ideal vital signs that require attention. In this Best Case Ever, in anticipation of our upcoming episode on A Rational Approach to Hyperkalemia Dr. Melanie Baimel describes a post arrest patient who remains bradycardic and hypotensive despite multiple pressors…. 

Published September 2016 by Anton Helman

Hyperkalemia is the Great ECG Imitator

Hyperkalemia can cause almost any dysrhythmia, but in particular, in patients who appear to be in “slow VTach” (ie. wide complex bradycardias), hyperkalemia should be high on your differential diagnosis. Not only can hyperkalemia cause almost any dysrhythmia, but the ECG in patients with hyperkalemia can even look like a STEMI, Brugada Syndrome or Benign Early Repolarization. One way to distinguish the ECG of a true STEMI from hyperkalemia with ST elevation is that the latter will usually show a right axis deviation.


Hyperkalemia mimicking Brugada Syndrome (care of Dr. Smith’s ECG Blog)

Classic hyperkalemia ECG progression

  • Peaked T wave – a sensitive sign is if the amplitude of the T exceeds the amplitude of the R, but one needs to think about early MI as well!
  • Prolonged PR interval and flattening of the P wave
  • Widening of the QRS
  • Sine Wave

Peaked T waves of hyperkalemia



Sine wave pattern – pathagnomonic for hyperkalemia


Dr. Helman and Dr. Baimel have no conflicts of interest to declare.


Mattu A, Brady WJ, Robinson DA. Electrocardiographic manifestations of hyperkalemia. Am J Emerg Med. 2000;18:721–729.

FOAMed Resources

EM Cases 2015 ACLS Guidelines Post Arrest Care Controversies Episode

Dr. Smith’s ECG Blog on Hyperkalemia Pseudoinfarction Patterns