What is going on guys? Don checking in. Welcome to Mint, where we bring nursing to you. So today we're going to talk about the easiest way to do your EKG interpretation. So if you're a nursing student or a new nurse who wants to do your EKG faster, stick around.
This video is for you. Alright guys, this is the 6-step EKG interpretation. So before we talk about the actual steps, we're going to discuss important concepts that will help us have a better understanding of what's going on inside the heart as it generates a heartbeat. The first concept that we are going to discuss is the conduction system of the heart.
The conduction system of the heart is pretty much these special cardiac cells right here that are responsible in conducting signals that cause the heart to contract. The first cell is called the heart. the SA node right here, or the sinoatrial node. By its name, sinoatrial, this cell is found within the right atrium of the heart.
This is also known as the natural pacemaker of the heart because this is where the beginning of the conduction takes place. So from the SA node, the conduction goes to the AV node or the atrioventricular node. By its name, this can be found within the border of the right atrium and the right ventricle. The AV node is also known as the gatekeeper of the heart. And the reason being is that it gets to decide whether what...
impulse to let through. So if the SA node generates a weak impulse or there is a block here somewhere, the AV node will perceive that and will decide not to let the impulse go through and instead it will conduct its own impulse. So from the AV node it goes to the single structure right here called the bundle of His and from the bundle of His the cells will continue and will bifurcate into two separate cells, one to the left and one to the right and this will now be called the left and right bundle branches. And from the bundle branches, they will extend within the apex of the heart.
They will be called the Purkinje fibers. So again, the conduction system of the heart begins at the SA node, goes to the AV node, next is the bundle of his, the right and the left bundle branches, and then eventually Purkinje fibers. So another concept that we need to discuss will be the inherit rate of these cardiac cells.
When you say inherit rates, these are pretty much the heart rate that we generate depending on which cardiac cell sends an impulse. So for example, if... If the SA node starts at all and it goes all the way to the Purkinje fibers, this will generate a heart rate of 60 to 100 mps.
It starts from here, goes all the way to the Purkinje fibers that will generate a heart rate of 60 to 100 mps. of 60 to 100 beats per minute. However, for some reason, if the SA node fails or there's a block somewhere here, then the AV node will kick in.
It will generate its own impulse. And when this happens, the AV node will generate a heart rate of 40 to 60 beats per minute. And that also includes the bundle of hiss.
The bundle of hiss also will generate its own impulse and it's enough to make 40 to 60 beats per minute. And And if the AV node or the bundle of his fail, then the left and the right bundle branches and the Purkinje fibers will generate their own impulse and they have the capacity to make a heartbeat up to 20 to 40 beats per minute. So now, let us talk about EKG.
It has different parts. We will start with this small bump right here called the P wave, followed by this tall structure right here called the QRS complex. And lastly, the last bump after the QRS complex would be the T-wave.
Let us discuss them one by one. Let's start off with P-wave. The P-wave represents atrial depolarization.
During atrial depolarization, the two atria are contracting. Next up, the QRS complex. Now, the QRS complex represents ventricular depolarization. During ventricular depolarization, polarization, the ventricles of the heart are contracting.
Depolarization is for contraction. So how would you know which one is which? That P wave is for atria while QRS is to ventricles. So if you look at the diagram right here, the QRS complex, it kind of looks like an inverted V. So V for ventricles.
So when you see a QRS complex, think about ventricular depolarization. So lastly, we have the T wave. The T wave represents ventricular repolarization. This is when the ventricles are relaxing. Keep in mind that every depolarization is always followed by repolarization.
So for every contraction will be followed by relaxation. That being said, the question is where is atrial repolarization? So if If QRS represents ventricular depolarization or contraction, and T-wave represents ventricular repolarization or relaxation, then where is atrial repolarization if this is depolarization? Well, it can be found within the QRS complex. As you can see, the QRS complex, it's a tall structure.
Because ventricles tend to contract stronger than the atria, they tend to mask the... atrial repolarization. And so that being said, atrial repolarization and relaxation takes place after the P wave, which can be found within the QRS complex.
Now, as a review, P wave stands for atrial depolarization. The QRS complex represents ventricular depolarization. The T wave is represents ventricular repolarization and the atrial repolarization is covered by the QRS complex.
You can't see it but it exists. So now let us talk about the segments and intervals in the EKG diagram. There are a bunch starting off with the PR interval, the PR segment, the QRS complex, the ST segment, and the QT interval.
But to make it easy for you guys, we are just going to talk about the PR interval and the QRS complex. These are all we need to do the EKG interpretation. The other segments, they are important too but we don't really need them to interpret an EKG faster and more efficient.
So this is your typical EKG strip. In an EKG strip, we have a big box and inside a big box, we have five small boxes. Each small boxes is equal to 0.04 seconds and so if in a big box there are five small boxes, that means that one big box is equal to 0.20 seconds. But really, as long as you know that one small box is 0.04 seconds, we're good to go.
So let us get on with our six-step EKG interpretation. First up, we have to identify and examine the P waves, measure the PR interval, measure the QRS complex, identify the rhythm, determine the heart rate, and interpret your strip. And we're going to talk about them one by one. Let's start off with identify and examine your P-waves right here.
The normal P-wave would be present and upright. If the P-wave is absent or inverted, then it could indicate a form of dysrhythmia such as a junctional rhythm. Next up, we are going to measure the PR interval.
PR interval is the distance between the beginning of the P wave and the beginning of the QRS complex. What we do is we count the number of small boxes in between and multiply it by 0.04 seconds. Our magic number for the PR interval is 0.12 to 0.20 seconds. Anything more than 0.20 seconds could indicate another dysrhythmia such as heart loss. Third would be to measure the QRS complex.
Just like the PR interval, we are going to measure the small boxes in between the QRS complex. Our magic number is 0.06 to 0.12 seconds. Anything more than 0.12 could indicate a dysrhythmia such as a PVC. Number four is we have to identify the rhythm of our trip.
It could be regular or irregular. And the way we do this is we measure the distance between R's. R's and R's. Some people use calipers to do this, but really all you need is an index card. Mark your R's and march them with the rest of the R's.
If they have the same distance, then your rhythm is regular. Otherwise, they are irregular. Fifth step is when we identify our heart rate.
Now before we calculate our heart rate, it is very important for us to know that our EKG is a six second strip. And the way we will know this is when we find these three lines right over here. If you see these lines, this means that from the first line up to the third line, that would be your six second strip.
The reason why this is important is that if it is a six second strip, then we can do a technique called the six second method. And the way we do this is that we count the number of R's between these three lines right here and multiply them by 10. So for this trip, we have 1, 2, 3, 4, 5, 6, and multiply that by 10. That will give us a heart rate of 60 beats per minute. One thing to remember is that this method works best for irregular rhythms. And another tip that I can tell you is that you have to be very very careful in using the six second method. You always have to verify that the strip that you're reading is indeed a six second strip.
I know some teachers include strips that appear to be six second strips but they're really not. They don't have these three lines right here. And students actually mess up the heart rate because they use the six second method.
This method only works for six second strips. Okay, second method that we can use to calculate the heart rate is the big box method. And the way this works is that we divide 300 by the number of big boxes between two Rs.
Our magic number is 300. So for this trip, we are going to use these two Rs right here. We have one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, for five big boxes in between ours. And so, using the formula, 300 divided by 5, we have 60 beats per minute. This method works better for regular rhythms only. And this is actually the method that you can use if you don't have a 6-second strip in front of you.
And the final step is, interpret your strip. So that is it for today guys. I hope you find that helpful. And if you haven't already, please hit the like and subscribe button. And let us know in the comment section below if you want us to make videos about dysrhythmias such as heart blocks or junctional rhythm.
And once again, my name is Don. Mint signing out.