Welcome to the channel where medical topics are made easy.
In this video, you’re going to learn a simple trick to remember the EKG changes that can
occur with hyperkalemia.
These changes are important to know, and this trick will always stick with you and you’ll
never forget it.
The trick only takes a few minutes to learn, so make sure to watch until the end.
We’re also going to go back to this table at the end, so don’t miss out on that.
You can find the notes, lecture, and study guide for the video linked down below.
Just a reminder that all the videos come with lectures and study guides, so make sure to
hit that subscribe button to not miss out.
Hyperkalemia is a medical term that means higher than normal potassium levels in the blood.
And this makes sense.
We know from our medical terminology videos that “hyper” means above normal, excess,
high, or elevated.
And “kalemia” means the presence of potassium in the blood.
So hyperkalemia refers to elevated levels of potassium in the blood.
The normal range of potassium for most labs is about 3.5-5.0 mEq/L.
This means that for most labs a value greater than about 5.0-5.5 mEq/L will be considered high.
Hyperkalemia can have many effects on the body, some of which can be life-threatening.
For example, potassium plays an important role in cardiac function and hyperkalemia
can lead to arrhythmias which is an abnormal heart rate or rhythm.
Some of these arrhythmias can be life threatening.
So it’s important to be able to recognize the EKG changes that can occur with hyperkalemia,
especially some of the early changes so it can be appropriately treated.
Let’s look at those changes now along with a simple way to remember them.
We’re going to see as we go through the video that the progression of EKG changes
seen with hyperkalemia usually correlates with the severity of the potassium level.
Generally speaking, the first EKG changes start to occur when potassium levels are greater
than 6.0 mEq/L.
However, this is not a hard-and-fast rule and EKG changes can happen sooner.
So the biggest take away point is the effects of high potassium, especially on the heart,
can vary from patient to patient.
Two patients could have the same high potassium level, and one could have minimal EKG changes
while the other has significant changes.
Having said that, there is a general progression of EKG changes seen with hyperkalemia.
And the trick to remember the EKG changes that can occur is to draw a counterclockwise
box of arrows like the one shown.
So let’s walk through how this works.
The first arrow to start with is the up arrow.
And the easy way to remember to start with the up arrow is to think of hyperkalemia which
is elevated levels of potassium in the blood.
Since we’re dealing with increased levels of potassium, this will help you remember
to start with the up arrow.
One of the first EKG change typically seen with hyperkalemia is peaked T waves.
Peaked T waves refers to a T wave with a higher than normal amplitude that gives a tall, peaked
or tented appearance.
And the up arrow will help you remember that.
Remember from our EKG video that the T wave represents ventricular repolarization.
If you need a quick refresher on the different components of an EKG, make sure to watch the
video on it linked below or in the cardiology playlist.
Peaked T waves generally occur when potassium levels are about 5.5-6.5 mEq/L.
Again, this is not a hard-and-fast rule and you might see peaked T waves outside that range.
The reason we see peaked T waves at potassium levels of 5.5-6.5 is because repolarization
abnormalities can occur at these levels.
And again remember the T wave represents ventricular repolarization.
After the up arrow, we move counterclockwise to the arrow pointing to the left.
The next EKG changes to occur are widening of the P waves and PR interval prolongation.
This refers to a P wave that is wider than normal and a longer time than normal between
the P wave and QRS complex.
And the left arrow will help you remember that.
Remember from our EKG video that the P wave represents atrial depolarization and the PR
interval represents the time from the start of the P wave which is atrial depolarization,
to the start of the QRS complex which is ventricular depolarization.
At potassium levels of 6.5-7.0 mEq/L is typically when you see P wave widening and PR interval
prolongation.
Again, this is not a hard-and-fast rule but just an average.
At potassium levels of 6.5-7.0 mEq/L is when progressive atrial paralysis can occur, which
is why you can start to see P wave widening and PR interval prolongation.
Remember the P wave and PR interval involve atrial depolarization and conduction through
the atria and eventually to the AV node.
So this is why you see changes to those EKG components here because they involve the atria,
and right now we have progressive atrial paralysis going on.
We'll continue to move counterclockwise to the down arrow.
As the atrial paralysis progresses, eventually the P waves may disappear.
This means there will be dropped P waves on the EKG.
And the down arrow will help you remember that.
Again the P waves represent atrial depolarization.
As potassium levels continue to climb, the atrial paralysis can progress.
We know from before that this can lead to P wave widening and PR interval prolongation.
But eventually it can lead to the P waves disappearing.
Dropped P waves can be seen at potassium levels of about 7.0 mEq/L.
Again, the P wave represents atrial depolarization which is why the P wave can disappear if the
atrial paralysis progresses.
Finally we have the arrow pointing to the right.
As potassium levels in the blood worsen and become more elevated, the QRS complex may
start to widen.
The easiest way to think about severe hyperkalemia is if you were to grab each end of the EKG
tracing and pull it to stretch it out.
You would widen the QRS complexes and eventually it could create a sine wave pattern.
The right arrow will help you remember this.
Remember from the EKG video that the QRS complexes represent ventricular depolarization.
At potassium levels of about 7.0-9.0 mEq/L, conduction abnormalities may be present.
This can include sinus bradycardia, AV heart blocks, slow atrial fibrillation, bundle branch blocks,
or fascicular blocks.
It's important to remember that the cardiac abnormality for hyperkalemia could just be
sinus bradycardia, so it's always good to keep hyperkalemia in the back of your mind.
As potassium levels continue to increase above 9.0 mEq/L, life threatening arrhythmias can
develop such as sine wave patterns, asystole, ventricular fibrillation, or PEA.
I put together a table that summarizes the EKG changes that can occur with hyperkalemia,
along with the arrow trick to remember those changes.
So hopefully this makes it easier for you.
Let’s briefly recap everything.
At potassium levels of about 5.5-6.5 mEq/L is when you might start to notice peaked
T waves on EKG.
This can be remembered using the up arrow.
T waves represent ventricular repolarization, and at potassium levels of about 5.5-6.5 is
when repolarization abnormalities can start to occur.
This is why we can see peaked T waves as a result.
As potassium levels increase to about 6.5-7.0 mEq/L, progressive atrial paralysis may start to occur.
This will lead to prolonged PR intervals and widening of the P waves on EKG, which can
be remembered with the left arrow.
Remember the P wave and PR interval represent atrial depolarization and the time it takes
for the electrical impulse to travel through the atria and AV node down to the ventricles.
This is why the progressive atrial paralysis affects the P wave and PR interval on EKG.
As potassium levels increase to about 7.0 mEq/L and the atrial paralysis continues to
progress, the P waves can disappear.
The dropped P waves can be remembered using the down arrow.
As potassium levels approach 7.0-9.0 mEq/L, conduction abnormalities can occur.
This can lead to widening QRS complexes, arrhythmias, and heart blocks.
The right arrow can be used to help you remember the widened QRS complexes and arrhythmias
that can occur, especially the slower ones like sinus bradycardia.
Potassium levels greater than 9.0 mEq/L can eventually lead to sine wave patterns and
life threatening arrhythmias such as asystole, ventricular fibrillation, or PEA.
This table along with the notes and study guide for this video can all be found linked
down below in the description and in the comments.
Hopefully this gave you a simple way to remember the EKG changes that can occur with hyperkalemia.
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