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Rapid EKG Interpretation | Identify Arrhythmias in 10 Seconds

ekg interpretation for nurses

Finally, identify any EKG rhythm in 10 seconds of less.  This podcast covers a SIMPLE 5 step method for rapid EKG interpretation and outlines the steps to help you quickly spot arrhythmias with confidence.  There are many more factors involved in fully understanding EKGs but this simple 5 step method will help you know exactly where to start.  If you work through the 5 steps in order you will be able to look at any strip any quickly notice abnormalities. You can view a PDF chart with essential heart rhythms and their criteria here.

  • Rate
  • P Wave
  • QRS Complex
  • P:QRS
  • PR – Interval

To get a FREE EKG Chart click HERE.


With any strip, you should start with the rate which can be determined (on a 6-second strip) by counting the P waves or the R waves and multiplying by 10.  You can also count the number of large boxes between R waves and divide 300 by that number.  For example, if you count 5 large boxes between each R wave than your rate would be approximately 60 bpm.  Identifying the rate is a good way to determine where the impulse is initiating and can quickly rule out sinus rhythm.

P Wave

The P wave is representative of atrial depolarization and the wave should have an upward direction, it should be visible, and smooth.  If you do not see P waves or they are misshapen you are not dealing with sinus rhythm.

QRS Complex

The QRS complex represents ventricular depolarization and should be present.  The complex should have a length of 0.06 – 0.12 seconds (1.5 – 3 small squares).  Anything out of this range is abnormal.


Every P wave should be followed directly by a QRS.  The ratio between P and QRS should be 1:1.  This represents the appropriate route of impulse travel.  Deviation or alteration from the impulse traveling from SA node through Purkenji fibers in the right direction may be identified with the P:QRS.

PR Interval

The PR interval represents the onset of atrial depolarization and the onset of ventricular depolarization and is a factor in determining how long the impulse is held in the AV node.  PR interval analysis is helpful in identifying AV heart blocks.  The PR interval should be between 0.12 – 0.20 seconds (3 – 5 small squares).


This is intended as a brief introduction into the basics of EKG interpretation and will help you identify arrhythmias in 10 seconds of less.  For a FREE PDF EKG Chart Click HERE.

Want to learn more about EKGs?  Check out our EKG course HERE!

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Podcast Transcription

Welcome to the NRSNG Podcast – the podcast created by nurses, for nurses. Are you

ready to take your learning to the next level? Sit back, and crank up the volume. Here’s

your host, Jon Haws.

This is Jon, welcome back again to another podcast episode of the

podcast. Today we’re going to be talking about 5 step interpretation of EKGs and how

you can quickly identify and analyze these rhythms to identify the rhythm that you are

seeing on the monitor or on the EKG strip.

We will be giving away a free EKG PDF chart that will help you have a quick reference

sheet to all the different rhythms that you need to know and the different criteria for each

of these 5 steps. If you want that chart, go to and you can get

that chart for free.

Lets go ahead and start.

First, to be able to quickly identify rhythms you need to understand very briefly how

electrical impulses travel through the heart. Every electrical impulse should start from the

SA node (sinoatrial node) which is located on the top of the right atria and that should

initiate an impulse that will then travel down to the AV note (atrioventricular node), which

sits in between the atria and the ventricles. That’s going to hold the impulse for a minute

before it then travels down to the bundle of His and then to the Purkinje fibers, which will

then depolarize the ventricles.

Start at the SA node, go to the AV node, travel down the bundle of His and then Purkinje

fibers, to depolarize the ventricles. That’s the normal mode of transportation.

Within the heart, we have three different pacemakers that will set the rate for the heart.

The first one is the SA node, as we talked about, the sinoatrial node that sits on the right

atria. That’s going to initiate an impulse every 60 to 100 times per minute, that’s why our

normal heart rate is going to be 60-100. Next, if the SA node isn’t able to fire, the AV

node can actually initiate impulses, 40 to 60 times per minute. If that ultimately fails, then

you have the Purkinje fibers that can also initiate their own impulse at 20 to 40 beats per

minute. That’s why it’s important that we understand the normal heart rate is 60 to 100

and analyze anything that is below that. We want to know if the person is bradycardic for

reasons other than just being athletic or an extreme resting state. If they are not initiating

impulse in the SA node, we need to know where that impulse may be coming from and

further analyze that.

There’s a couple complexes and waves that we are going to identify on a rhythm strip.

First we have our P wave, we have our Q wave, R wave, S wave and T wave. There are

a few more waves but these are the ones that we are going to identify; P, Q, R, S and T.

And then we have our PR interval, which goes from the beginning of the P-Wave to the

beginning of the QRS complex. And then we also have our QRS complex – the QRS

complex makes up the QRS waves and that’s going to identify ventricular depolarization.

For our needs in identifying our rhythms quickly, we’re going to look at our rate, our P

wave, our QRS complex, our PR interval, and the P to QRS ratio.

P wave is going to identify atrial depolarization.

QRS complex represents ventricular depolarization.

PR Interval represents the onset of atrial depolarization to the onset of ventricular


The five things again that we are going to identify to interpret our rhythms is going to be

our (1) rate, (2) P waves, (3) our P wave to QRS complex ratio, (4) our QRS complexes

and (5) our PR interval.

A normal rate is going to be 60 to 100 beats per minute. There’s a couple ways to

identify what your rate is. If you’re looking at a 6 second EKG strip then you can just take

the amount of beats in the 6 seconds and multiply it by 10. If you don’t have a 6 second

strip or you want to get a little more accurate, then you can identify your R waves or your

P waves, count how many large boxes are between those and divide 300 by that

number. So for example, if you identify your R waves and you note that there are 6 large

boxes between those two R waves, then your rate is going to be 50 beats per minute.

Next thing after rate that we’re going to look at is our P waves. We want to notice that

there are P waves present, that they are upright and that they are smooth – that they

aren’t jagged or sharp. So we want P waves to be present, we want them to be upright

and we want them to be smooth.

Next we’re going to notice if we have QRS complexes. We want to notice if our QRS

complexes are present and we want to count the number of small boxes between our Q

and our S. We want there to be 1.5 to 3 small boxes between our Q and our S waves.

So we want present QRS complexes and we want 1.5 to 3 small boxes between the Q

and the S.

Next we want to notice the P to QRS ratio. We want there to be a P wave before every

QRS and we want there to be one P wave for each QRS. So there needs to be a P wave

for every QRS and the P wave needs to come before the QRS complex.

The last thing we’re going to identify in our 5-step method is going to be our PR interval.

Know, the PR interval starts at the beginning of the P wave to the beginning of the QRS

and we want there to be 3 to 5 small boxes. So you’re going to count the number of

small boxes between those two and you want there to be 3 to 5 small boxes.

So first, rate, then P waves, then QRS, then P to QRS ratio and then PR interval. That’s

how we’re going to identify our rhythms.

One more time, we’ll go through it.

We want to identify our rate. We want our rate to be between 60 to 100 beats per

minute. We want to then look at our P waves. We want there to be present P waves, we

want them to be upright and we want them to be smooth. Next we’re going to look at our

QRS, we’re going to make sure that there are QRS complexes, that they are 1.5 to 3

small boxes between the Q and the S. Then we’re going to notice our P to QRS ratio, we

want that to be a 1:1 ratio for every P, there is a QRS and the P comes before the QRS.

Then we are going to look at our PR interval. We want that PR interval to be about 3 to 5

small boxes.

So as you go through these checklists as you look at a rhythm, you can quickly start

identifying what the rhythm is and you can start eliminating specific rhythms based on

each of these criteria. First of all, if you look at your rhythm and your rate is 150, you can

already eliminate sinus rhythm, because it’s greater than 100. If you go there and look at

your PR interval is greater than the 5 boxes you’re going to start looking at some of your

heart blocks – that the impulse is being held in the AV node too long. If you start seeing

the P waves are either absent or going downward rather than upward and smooth, you

might start looking at junctional rhythms.

To really understand this, I really recommend that you go to

and you just download that free chart. That will really help you look through the criteria

for each of the different rhythms that you are looking at and give you kind of a practice in

identifying rhythms and working through these 5 criteria. But if you work through these 5

criteria, you’ll be able to identify any rhythm and quickly be able to rule out specific

arrhythmias, and determine if its sinus rhythm or it may be more of a lethal rhythm or if it

might just be a little nuance that you may not have seen if you haven’t worked through

these 5 steps.

So that’s going to be my suggestion. This is just a quick podcast on what you’re looking

at. We aren’t really going to go into the different arrhythmias here, and we may go into

that later. But with every strip that you look at, first look at rate, look at P waves, look at

your QRS complex, look at your P to QRS ratio then look at your PR interval. We also

have a video on YouTube about this. Our channel is NRSNG Com. Check it out – Kevin

has a video and looks through a couple strips in his examples. Best way to do it though

is go to that and that will help you identify these rhythms. I

appreciate you listening and we’ll talk to you soon.

Visit us at for disclaimer information and to keep the learning going.

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