Cardiac Conduction System and Basics of EKG

so this lecture is going to cover parts of the cardiac conduction system before we can really start talking about dysrhythmias um which are presented in chapter 34 and that's where you're going to find most of the material that I cover in this Camtasia we need to talk about the conduction system you probably remember the conduction system from a and P but I know for some of us it's been a while since we've had a MP so I always like to do a little review remember that electrical impulses they're caused by pacemaker cells these pacemaker cells are located in the heart what happens is they transmit electrical activity to other cardiac cells the dominant pacemaker of the heart is the SA node this is where the impulse actually originates and so when you're looking at the SA node when it originates when it conducts those electrical impulses it's going to originate at a rate of 60 to 100 beats per minute so your SA node is your dominant pacemaker of the heart after your after it goes to your SA node right over here in this little picture then it goes to your AV node once it's in the AV node it just holds the impulse for a very short period of time and then it sends it on through the ventricles so when you're looking at rates in the AV node your rate now is going to be 60 to 40 beats per minute and then the last part of the conduction system is right down here and it's your bundle branch system and so that's your purge in G fibers and your bundles of hiss if that completes conduction but what I want you to look at is look at your rate right here 40 to 20 so remember that your normal heart rate is 60 to 100 beats per minute and so when you start getting in the 20s and 40s realize that your person is not going to be doing too hot right here you have to worry about decreased cardiac output so this right here is your conduction system it goes SA node to AV node to bundle branch system so that right there is a conduction system of the heart as I told you your SA node that is your dominant pacemaker but the neat thing about our heart is we have cups so if for say whatever reason your si note doesn't work then you have an AV node that can take over or you even have to have a bundle branch system but what you have to look at is when it's not originating the SA node look at what your rate will be right here okay 6240 I'm a fit sixty your person probably is not having any type of signs of cardiac compromise but realize as the rate drops your person signs and symptoms of cardiac compromise become higher so just be aware of that so one thing that we need to talk about is EKG paper don't let the terminology confuse you some people say EKG some people say ECG they are the same thing I'm typically if someone says EKGs it's because they've been a nurse for a little while and that used to be the going terminology but the neat thing about an EKG it actually provides a graphic representation a picture really of what the heart's electrical activity is doing at that time and so it's really really neat it lets us look at the electrical conduction system of the heart so some things you want to remember when you are obtaining an EKG is you want to make sure that your patient is learning in a semi-reclined position that they're breathing normally and that you don't place any type of electrodes over any type of irritated or scar tissue because that could make the reading not be as accurate also realize there's lots of different types of EKGs you have a six lead you have a 12 lead EKG all of those leads are put on different parts of the body and it lets us look at different representations of the heart or different views of the heart per se so some things we can tell just by looking at an EKG we can see where is the heart in orientation of the chest we can also figure out do they have any type of ischemia or do they have any type of electrical issues going on we can look at what's their electrolytes from this any type of conduction disturbance so we can get a lot of information from an EKG so as I told you there's multiple leads for this class purposes what I need you to realize is we want to read an EKG and lead to so once you get done with this I want you to go find an EKG on the internet and look at the paper the paper has you have to have EKGs paper and EKG paper is just lined paper and those lines they mean different things to us and I'm going to go into that and just probably two more slides but on the sides of the EKG paper they have room and numerals depending on how many leads you have it has different numbers so you want to go to Roman numeral two and look at it that's the lead we want to look at because that tells us that that gives us the biggest overall picture of the hearts conduction system and what's going on so if there are specific areas we want to look at you'll see your healthcare providers say well I want to look at lead 3 or lead 4 because that shows different areas of heart but for this class remember my goal is that you learn to recognize all the parts of an EKG and you start recognizing strips okay so I want you to always lead read everything in lead to as I told you this is a great example of EKG paper it's blind it's made up of boxes and these boxes have some of them have darker lines they have lighter white lines inside of them this right here is just pink but some of your EKG paper is gray and black it just kind of depends but really what I wanted you to realize is that EKG paper you have to have it when you're reading an EKG because these little boxes they're significant for us when you are reading EKG paper remember each one of these little boxes so this right here I always like to don't don't get confused in my picture here but this is the overall EKG paper right here okay and I just had them take one of these little boxes and then one of these I took out and then I took out again just so you can see how actually how small they are so every one of the little boxes so this box right here would equate to just one of these tiny little boxes right here is one millimeter wide by one millimeter high so when you're reading you have two things we look at we look at horizontal and we look at vertical axis so your horizontal is what we're going to look at the most in this class you get more into the vertical when you get into a three which is a little bit more advanced cardiac but horizontal axis that equals time for us each one of these little boxes it means something so I told you this little box right here is one millimeter by one millimeter so we equate that to time so each one of these tiny little boxes up here it's 0.04 seconds okay and that's important to us because you're gonna see as we start reading them why we need to know x so we stayed our x in seconds so what happens is each one of these so this came out so each one of these larger boxes okay because see this picture right here we just kind of broke this down so each one of these boxes they're 0.2 zero seconds okay and then just kind of make it easier for you five large boxes is one second 15 large boxes is three seconds and 30 large boxes is six seconds and you're like well why do I need to know that okay so remember I've just told you that when you read an EKG you are going to read it and lead to the other thing you need to realize is when we try and see what's going on the overall picture of the conduction system we need at least a six second strip okay so that's why you need to be able to pick out 30 large boxes 6 second strips ok so that is why you need to know 15 large boxes is 3 seconds 30 large boxes is 6 seconds now the neat thing is most your EKG paper now they have a hash mark and these hash marks are really neat because they specifically tell you they tell you a three-second interval and so then you would just go from hashtag to hashtag the hashtag and you would have six seconds and you'd be able to read it on there for testing purposes any strip that I give you you it is safe to assume it is a six second strip okay because remember guys I'm just introducing you to EKGs and so that's what I want you to get in your head is that thirty large boxes is six seconds so what I like to do before I start trying to talk about all the different dysrhythmias I take apart the cardiac cycle we talk about every single component and then we put it all together so for some of y'all that are a little bit more advanced on the cardiac side or let's say your telemetry text or you're already opens and you knew how to read it EKG this might seem like I'm breaking it down too much but it just works really well when I start small and then I build up so just bear with me for a little bit but your P wave that is the first wave in the cardiac cycle your PA wave actually represents the firing in the SA node so remember when the SA node fires then you have atrial depolarization meaning the heart contracts and it continues to spread the impulse throughout so as you can see right here this is the P wave the first wave so before I can talk to you about a P wave I have to show you baseline that's the first thing you want to realize when you're reading strips is what is baseline so I have it nice and color-coded here but here is your EKG paper right here and this right here is your baseline okay it's the black area and when it starts to deviate up or down from baseline then that is the beginning of your P wave so as you can see when it starts to turn yellow that is the beginning of your P wave and that's that progresses you see how it returns back to baseline okay so this is just a great representation of that so this is your P wave it is the first wave in a cardiac cycle I always like to think about a P wave kind of like a little hilltop right here okay a normal P wave when you're looking at it it should be smooth and round so this is another example I have so again look right here so you see baseline is where my little arrow is okay I'm usually in front aboard doing this so bear with me but here's my little arrow this is baseline you see where it starts to come up right here with these little marks are this is the beginning of my P you follow it around and then when it returns to baseline Gus that is the end of my pee this whole thing right here this is the p-wave so it begins right here and it ends right here this is the first wave in the cardiac cycle so when you're looking at P waves some things you need to make note of normal P waves are very smooth and rounded they are upright and lead to so we remember I tell you for this part that clot this class purpose is we are reading EKGs in leap - and it should be more no more than point 1 1 seconds and duration so that's it should be no more than two and a half boxes so when you look right here and you measure from here to here you see that's about two and a half boxes ok because there's one there's two there's a little piece of one right there and there's a little piece of one right there so this is a normal P wave so if I'm gonna tell you normal P waves well then you know I got to throw some abnormals in there so here are some great examples of abnormal P waves this one right here the first thing I want to put my arrow at his baseline you've got to be able to find baseline before you can find anything else here so this right here is baseline okay so where it starts to come up this is the beginning of my P and you just fold around and you see where it comes back down to baseline that is the end of my P this right here is a normal piece you know it's smooth and round on each side and it's no more than two and a half boxes this is normal okay so let's look at this up this one right here we all find baseline look right here and make sense practice this is your baseline right here well it starts to go up and we're going to follow it back down to baseline but you see as it goes up you have this little notch here in the middle it comes back and then it goes back to baseline this right here is what we call a notched P wave okay so if you have notched P waves that could be simply caused by an enlarged atria so things that cause enlarged Atreus just some examples I can just think of COPD congestive heart heart failure any type of valve disease they can cause notched p-waves so then we have a Pete P wave again here is your baseline right here it starts to come up it Peaks and then it comes back down to baseline this is a pete see how it's not normal because it's not smooth and rounded so the causes of a Pete's P wave are the same as they are for the knotch so it's usually due to some type of enlargement of the atria and then you have inverted at piece so inverted means instead of going up it's going down so again let's look at baseline my little area right here is on baseline okay we follow it down and we go back around and come back to baseline and it's inverted so that right there tells us it's it's not normal an inverted P wave it's going down meaning it's going below baseline because the this is baseline right here okay and it returns right here anything below it is considered negative or we call it negatively deflected and anything that's above baseline I'm for example like this would be above baseline we call that positively deflected so those are just some terminologies for you but these are things that are abnormal P waves that you would need to investigate a little further if you were looking at someone's EKG and you saw these so we talked about the P wave the P wave is the first cycle or they should say the first wave in the cardiac cycle so let's move on to the Q wave so your Q wave is the first negative or downward deflection that follows the P waves we read and lead to and it should always be negative meaning going below baseline when you look at your Q wave what it's representing is just depolarization of the the septum that is what it's representing so let's look right here I have another little picture okay so let's practice baseline because the only way you're going to learn EKGs is you just have to practice so right here this is baseline I think we we're good with baseline where it starts to come up this is your P it comes to a peak and then it comes back down so no this is not a normal P because remember it's peaked it's not smooth but your P comes back down and when it goes below baseline right here that is your Q wave guys okay where it goes below baseline this is your Q wave okay so following your Q wave you have your R wave so when you're looking at your R wave remember it's the first positive deflection that follows the P wave so let's look right here let's start over again okay because we definitely need the practice this is baseline this is where it starts to come up and so this is the beginning of your P okay you keep following your P you see how it's going back to baseline right here okay so it's back at baseline right where my little arrow is it's that layer just disappeared okay it's it's baseline right here okay and then you see where it starts to go downward because remember your Q wave is your first negative deflection meaning it's going to be below baseline so if baseline is right here then this right here is your Q where it had where it shows it okay so then what you're going to see is you're going to have a positive deflection so this positive deflection this is your R wave okay and our waves typically guys when you're looking at EKGs they're pretty easy to pick out because they're usually the tallest the tallest wave in the cardiac cycle so they're they are pretty easy to follow out so you just look at your R wave and then it's going to come back down to baseline and then we're going to follow it up with an S wave so your s-wave is the negative wave form that follows the are so again let's practice this is our P this is the beginning of our P here's our P our P comes back to baseline right here okay follow it over this is baseline up you see where it starts to come down well that right there that is the beginning of your Q and then where it goes back to baseline that starts your R okay you follow it up this all this whole thing right here is your is your R okay so you follow it up and then you see when it is at baseline then what happens is it goes below baseline and once it goes below baseline down here this is your s so the reason I take each one of those apart is because typically when you read it you read it as a QRS so let's let's practice on these remember your cure s is follow normally a p-wave so baseline here is your P wave you see it goes up it comes back down to baseline okay you see where it starts to go below baseline this is your Q and then it comes up this is your R and then it goes back to baseline and then when it goes below baseline guys that's your s that is your cure s complex and so when you're looking at your QRS complex some things you need to realize is that a normal range for a cure s complex is point zero six two point ten seconds so it shouldn't be more than three small boxes remember that the Cure s it represents the spread of electrical impulses through the atria okay so the reason I always like to tell you that is when we're reading strips if you know if you're looking at your QRS and you're curious is abnormal or it doesn't something's not right with it well then you know you got an issue somewhere and your ventricles if you're looking at a strip and you look at these P waves and there's something going on with your P waves remember I told you that p-waves represent depolarization of the atria and you know something's wrong with your atria so that's just I would like to throw that out there when you are reading strips those are two things that you really want to keep in mind as I told you you're curious you have a Q and R and an S wave so again let's go back I gave you normal nice pretty QRS okay so I got up throw some abnormals in there okay or it just wouldn't be nursing so an abnormal Kuras is anything that is less than point zero four so less than one small box or greater than point one zero so that's your so no more than three small boxes so that's your range if it is less than or greater than then we consider it abnormal and so that's what you want to realize when you see these so abnormal qrs's they let you know that something's going on in the ventricle and so you would need to do a little bit further investigation here so then let's talk about our T wave so your T wave represents ventricular repolarization so this is kind of where your heart is resting it's getting ready to start going again so this is where your heart is most vulnerable to any type of extra stimuli so you got to be careful about that guys when you're looking at your T wave and you're wanting to figure out well where where is my T wave the best thing that you want to do is it follows your cure s and it's a positive deflection following the return to baseline for your QRS so look right here and let's go through the whole cycle again this is baseline right here okay you see where it starts to come up this is the beginning of your P okay it comes back to baseline right here this is the end of your P this is baseline and you see where it starts to go down that right there that is the beginning your cue okay and so here is your cue it starts to here's baseline it comes up it comes to baseline and this is your are okay when it goes below baseline you're at your s and then it goes it when it comes back over here we're looking to where it goes back to baseline and then your first positive deflection following that where it starts coming up again this right here is your T wave okay so guys all of this right here this is like this is a cardiac cycle so remember a normal T wave is slightly slightly asymmetric I like to think about T waves if you're compare them because I always have students say well my P waves and mighty ways oh I can't tell a difference so two points that would help you with that one when you're looking at P waves they should look like little hilltops they should be symmetrical on each side kind of nice nice and smooth and round but your T waves they're slightly asymmetrical so I think about them as mountaintops you're having to climb up one side to get to the top so one side is going to look a little off than the other one at for example here are your here's some normals right here these first ones that my arrows are circling right here okay so this right here this is your T and then here is your P so look at that you see how it's slightly asymmetrical when it comes up same thing right here it's slightly asymmetrical okay so those are some those are just my tips really for how do you tell a P wave from a t way the other thing is remember look at your cure s complex this is your R this is always the easiest thing to find as your R well you know if it's before the QRS complex it's your P if it's after like right here where my arrow is it's your T so those are two tips to try and try to help you get it straight in your head so we look at T waves a lot if we have inverted T waves like we see here okay these are inverted T waves we are very concerned about that because that shows us or that lets us know there's been some type of myocardial ischemia okay so we get really worried about worried about that and the reason that is is remember that your heart is made up of cells cells need oxygen to survive and when someone has ischemia they're not getting the oxygen they need to be able to function so we worry about inverted ones but then you know what we don't really want these tall peaked ones that you see here also when you see really tall Pete remember it comes up to a point like this one right here when you see these then what I always want you to think about is oh my goodness what is there potassium level because typically you will see these in people that have very high potassium levels so these are just some abnormals that you're going to come into contact with when you are in practice I always like to make mention of a you wave you probably will not see a you wave too often and we don't know that much about you waves we think and I put it on here we think it's actually the repolarization of some of the fibers in the heart but we're not positive what we do know is we see you waves most often and people that have a very slow rate because they're easier to see because they're very small as I told you usually they're less than a third the size of a tea wave and so also realized some people have you waves and it doesn't mean anything however what you as a nurse should realize is that if you see a you wave a lot of times it means that patient has low potassium level and so what you would want to do is you and want to get an order to check their potassium level if they haven't hang on recently or you go look at their potassium level let's say if they've had one that day and see if it's within normal limits so it's just kind of one of those if you see one you really need to go and look and if you see one and it looks abnormal it looks larger then you're t-wave you really want to be thinking what's this person's potassium level let me let me check it out so that's why I always like to mention it okay so it's not always a tried-and-true meaning that person's going to have a Troi imbalances but if you see one it's always best to be safe and let's look at their labs let's get something ordered here are some example of you waves so as you see right here this is a really slow it's real pretty but it's a really slow right so these you waves are very easy to see and I have them highlighted in red right here so I always like to start at the top so this right here this is baseline okay this where it starts to come up this is the beginning of your P you follow it around till it comes back to baseline that's the end of your P guys okay and so Aaron atheria and so what you're going to do is you're going to where it goes below baseline that's the beginning of your Q right here it comes back to baseline and then it comes up this is your R guys it stays your R until it comes back to baseline here's baseline and then oh look it drops okay so this is your s and then what happens is it comes back to baseline right about here okay so you follow it you see where it starts to go up this is the beginning of your to you eight and it comes back to baseline this is the end and then look it's just this extra little wave you have right here that follows your T wave okay and this is called au wave so when you see a u wave you better go check their potassium level and see what it is so I talked about waves now I want to go back and pick up with some intervals and I know this seems really overwhelming now but it will make sense when I start to put everything together and just realize you're not going to get this all at one time so you need to take little breaks and come back and make sure that you understand this before you go forward so that you don't mess yourself up and get confused so a PR interval it represents the beginning of the HR depolarization - beginning of the ventricular depolarization so when we measure a PR interval we measure it from the beginning of the P wave to the beginning of the Q our complex okay so I've highlighted it right here for you so when you're looking right here again this is baseline okay this right here this is the beginning of the P you follow it all the way around okay you're back at baseline guys now you keep following it and when it goes below baseline that right there is the beginning of your curious complex so this is what you would measure right here so essentially what that's telling us that PR interval is telling us how long it takes for the impulse to get from the atria to the ventricle this PR interval is telling us that okay it should be between point one two and point two and point two zero so no more than five small boxes some things that can call cause a abnormal PR interval if it's too long it could be because they have something called a first degree block which we will learn about that shortly or they could have digitoxin e that can also cause a prolonged PR interval so I talked about PR interval let's talk about s T interval so s T interval looks at or I should say it represents the end of the ventricular depolarization to the beginning of ventricular repolarization so we measure s T interval from the end of the S wave to the beginning of the T wave okay your normal range should be no more than point zero four seconds okay so remember what is zero point four seconds is okay no more than it should be no more than one box okay so when you're looking at this right here the reason we look at that's the interval is because this s T interval if it has if it's abnormal okay meaning this s CM s the interval if it's elevated meaning really a payer or if it's the Pres meaning less less than R down down below here of greater than two millimeters well that tells us that that person has some type of myocardial ischemia and or injury you see that often in people who are having or have had an mi so that's one reason when someone comes in with chest pain we always look at the ST segment and see kind of what's going on so ST segment and then also your t way those are our two big ones that we look at when we suspect that someone's having an mi so guys this is this is everything we just covered we covered the P the QRS the T so let's kind of do a little recap in a little review this is baseline where it starts to come up that's the beginning of your P you follow it around till it comes down that's the end of your P okay then what you want to look at right here this you follow your baseline your Q starts where it starts to deviate down because remember your Q is negative so it's negative here and then here's baseline when it starts to come up see where it's starting to come up this is your R right here okay and then when it deviates down below baseline that's your s and then it comes back to baseline here baseline and then when it starts to come up this is the beginning of your T and when it returns to baseline that is the in D or T so guys this is kind of everything we just covered and so you need to go back and review again that chapter in your book that talks about cardiac dysrhythmias it goes into each one of these and it breaks it down so that's a great resource for y'all to use for this section

so this lecture is going to cover parts of the cardiac conduction system before we can really start talking about dysrhythmias um which are presented in chapter 34 and that&#39;s where you&#39;re going to find most of the material that I cover in this Camtasia we need to talk about the conduction system you probably remember the conduction system from a and P but I know for some of us it&#39;s been a while since we&#39;ve had a MP so I always like to do a little review remember that electrical impulses they&#39;re caused by pacemaker cells these pacemaker cells are located in the heart what happens is they transmit electrical activity to other cardiac cells the dominant pacemaker of the heart is the SA node this is where the impulse actually originates and so when you&#39;re looking at the SA node when it originates when it conducts those electrical impulses it&#39;s going to originate at a rate of 60 to 100 beats per minute so your SA node is your dominant pacemaker of the heart after your after it goes to your SA node right over here in this little picture then it goes to your AV node once it&#39;s in the AV node it just holds the impulse for a very short period of time and then it sends it on through the ventricles so when you&#39;re looking at rates in the AV node your rate now is going to be 60 to 40 beats per minute and then the last part of the conduction system is right down here and it&#39;s your bundle branch system and so that&#39;s your purge in G fibers and your bundles of hiss if that completes conduction but what I want you to look at is look at your rate right here 40 to 20 so remember that your normal heart rate is 60 to 100 beats per minute and so when you start getting in the 20s and 40s realize that your person is not going to be doing too hot right here you have to worry about decreased cardiac output so this right here is your conduction system it goes SA node to AV node to bundle branch system so that right there is a conduction system of the heart as I told you your SA node that is your dominant pacemaker but the neat thing about our heart is we have cups so if for say whatever reason your si note doesn&#39;t work then you have an AV node that can take over or you even have to have a bundle branch system but what you have to look at is when it&#39;s not originating the SA node look at what your rate will be right here okay 6240 I&#39;m a fit sixty your person probably is not having any type of signs of cardiac compromise but realize as the rate drops your person signs and symptoms of cardiac compromise become higher so just be aware of that so one thing that we need to talk about is EKG paper don&#39;t let the terminology confuse you some people say EKG some people say ECG they are the same thing I&#39;m typically if someone says EKGs it&#39;s because they&#39;ve been a nurse for a little while and that used to be the going terminology but the neat thing about an EKG it actually provides a graphic representation a picture really of what the heart&#39;s electrical activity is doing at that time and so it&#39;s really really neat it lets us look at the electrical conduction system of the heart so some things you want to remember when you are obtaining an EKG is you want to make sure that your patient is learning in a semi-reclined position that they&#39;re breathing normally and that you don&#39;t place any type of electrodes over any type of irritated or scar tissue because that could make the reading not be as accurate also realize there&#39;s lots of different types of EKGs you have a six lead you have a 12 lead EKG all of those leads are put on different parts of the body and it lets us look at different representations of the heart or different views of the heart per se so some things we can tell just by looking at an EKG we can see where is the heart in orientation of the chest we can also figure out do they have any type of ischemia or do they have any type of electrical issues going on we can look at what&#39;s their electrolytes from this any type of conduction disturbance so we can get a lot of information from an EKG so as I told you there&#39;s multiple leads for this class purposes what I need you to realize is we want to read an EKG and lead to so once you get done with this I want you to go find an EKG on the internet and look at the paper the paper has you have to have EKGs paper and EKG paper is just lined paper and those lines they mean different things to us and I&#39;m going to go into that and just probably two more slides but on the sides of the EKG paper they have room and numerals depending on how many leads you have it has different numbers so you want to go to Roman numeral two and look at it that&#39;s the lead we want to look at because that tells us that that gives us the biggest overall picture of the hearts conduction system and what&#39;s going on so if there are specific areas we want to look at you&#39;ll see your healthcare providers say well I want to look at lead 3 or lead 4 because that shows different areas of heart but for this class remember my goal is that you learn to recognize all the parts of an EKG and you start recognizing strips okay so I want you to always lead read everything in lead to as I told you this is a great example of EKG paper it&#39;s blind it&#39;s made up of boxes and these boxes have some of them have darker lines they have lighter white lines inside of them this right here is just pink but some of your EKG paper is gray and black it just kind of depends but really what I wanted you to realize is that EKG paper you have to have it when you&#39;re reading an EKG because these little boxes they&#39;re significant for us when you are reading EKG paper remember each one of these little boxes so this right here I always like to don&#39;t don&#39;t get confused in my picture here but this is the overall EKG paper right here okay and I just had them take one of these little boxes and then one of these I took out and then I took out again just so you can see how actually how small they are so every one of the little boxes so this box right here would equate to just one of these tiny little boxes right here is one millimeter wide by one millimeter high so when you&#39;re reading you have two things we look at we look at horizontal and we look at vertical axis so your horizontal is what we&#39;re going to look at the most in this class you get more into the vertical when you get into a three which is a little bit more advanced cardiac but horizontal axis that equals time for us each one of these little boxes it means something so I told you this little box right here is one millimeter by one millimeter so we equate that to time so each one of these tiny little boxes up here it&#39;s 0.04 seconds okay and that&#39;s important to us because you&#39;re gonna see as we start reading them why we need to know x so we stayed our x in seconds so what happens is each one of these so this came out so each one of these larger boxes okay because see this picture right here we just kind of broke this down so each one of these boxes they&#39;re 0.2 zero seconds okay and then just kind of make it easier for you five large boxes is one second 15 large boxes is three seconds and 30 large boxes is six seconds and you&#39;re like well why do I need to know that okay so remember I&#39;ve just told you that when you read an EKG you are going to read it and lead to the other thing you need to realize is when we try and see what&#39;s going on the overall picture of the conduction system we need at least a six second strip okay so that&#39;s why you need to be able to pick out 30 large boxes 6 second strips ok so that is why you need to know 15 large boxes is 3 seconds 30 large boxes is 6 seconds now the neat thing is most your EKG paper now they have a hash mark and these hash marks are really neat because they specifically tell you they tell you a three-second interval and so then you would just go from hashtag to hashtag the hashtag and you would have six seconds and you&#39;d be able to read it on there for testing purposes any strip that I give you you it is safe to assume it is a six second strip okay because remember guys I&#39;m just introducing you to EKGs and so that&#39;s what I want you to get in your head is that thirty large boxes is six seconds so what I like to do before I start trying to talk about all the different dysrhythmias I take apart the cardiac cycle we talk about every single component and then we put it all together so for some of y&#39;all that are a little bit more advanced on the cardiac side or let&#39;s say your telemetry text or you&#39;re already opens and you knew how to read it EKG this might seem like I&#39;m breaking it down too much but it just works really well when I start small and then I build up so just bear with me for a little bit but your P wave that is the first wave in the cardiac cycle your PA wave actually represents the firing in the SA node so remember when the SA node fires then you have atrial depolarization meaning the heart contracts and it continues to spread the impulse throughout so as you can see right here this is the P wave the first wave so before I can talk to you about a P wave I have to show you baseline that&#39;s the first thing you want to realize when you&#39;re reading strips is what is baseline so I have it nice and color-coded here but here is your EKG paper right here and this right here is your baseline okay it&#39;s the black area and when it starts to deviate up or down from baseline then that is the beginning of your P wave so as you can see when it starts to turn yellow that is the beginning of your P wave and that&#39;s that progresses you see how it returns back to baseline okay so this is just a great representation of that so this is your P wave it is the first wave in a cardiac cycle I always like to think about a P wave kind of like a little hilltop right here okay a normal P wave when you&#39;re looking at it it should be smooth and round so this is another example I have so again look right here so you see baseline is where my little arrow is okay I&#39;m usually in front aboard doing this so bear with me but here&#39;s my little arrow this is baseline you see where it starts to come up right here with these little marks are this is the beginning of my P you follow it around and then when it returns to baseline Gus that is the end of my pee this whole thing right here this is the p-wave so it begins right here and it ends right here this is the first wave in the cardiac cycle so when you&#39;re looking at P waves some things you need to make note of normal P waves are very smooth and rounded they are upright and lead to so we remember I tell you for this part that clot this class purpose is we are reading EKGs in leap - and it should be more no more than point 1 1 seconds and duration so that&#39;s it should be no more than two and a half boxes so when you look right here and you measure from here to here you see that&#39;s about two and a half boxes ok because there&#39;s one there&#39;s two there&#39;s a little piece of one right there and there&#39;s a little piece of one right there so this is a normal P wave so if I&#39;m gonna tell you normal P waves well then you know I got to throw some abnormals in there so here are some great examples of abnormal P waves this one right here the first thing I want to put my arrow at his baseline you&#39;ve got to be able to find baseline before you can find anything else here so this right here is baseline okay so where it starts to come up this is the beginning of my P and you just fold around and you see where it comes back down to baseline that is the end of my P this right here is a normal piece you know it&#39;s smooth and round on each side and it&#39;s no more than two and a half boxes this is normal okay so let&#39;s look at this up this one right here we all find baseline look right here and make sense practice this is your baseline right here well it starts to go up and we&#39;re going to follow it back down to baseline but you see as it goes up you have this little notch here in the middle it comes back and then it goes back to baseline this right here is what we call a notched P wave okay so if you have notched P waves that could be simply caused by an enlarged atria so things that cause enlarged Atreus just some examples I can just think of COPD congestive heart heart failure any type of valve disease they can cause notched p-waves so then we have a Pete P wave again here is your baseline right here it starts to come up it Peaks and then it comes back down to baseline this is a pete see how it&#39;s not normal because it&#39;s not smooth and rounded so the causes of a Pete&#39;s P wave are the same as they are for the knotch so it&#39;s usually due to some type of enlargement of the atria and then you have inverted at piece so inverted means instead of going up it&#39;s going down so again let&#39;s look at baseline my little area right here is on baseline okay we follow it down and we go back around and come back to baseline and it&#39;s inverted so that right there tells us it&#39;s it&#39;s not normal an inverted P wave it&#39;s going down meaning it&#39;s going below baseline because the this is baseline right here okay and it returns right here anything below it is considered negative or we call it negatively deflected and anything that&#39;s above baseline I&#39;m for example like this would be above baseline we call that positively deflected so those are just some terminologies for you but these are things that are abnormal P waves that you would need to investigate a little further if you were looking at someone&#39;s EKG and you saw these so we talked about the P wave the P wave is the first cycle or they should say the first wave in the cardiac cycle so let&#39;s move on to the Q wave so your Q wave is the first negative or downward deflection that follows the P waves we read and lead to and it should always be negative meaning going below baseline when you look at your Q wave what it&#39;s representing is just depolarization of the the septum that is what it&#39;s representing so let&#39;s look right here I have another little picture okay so let&#39;s practice baseline because the only way you&#39;re going to learn EKGs is you just have to practice so right here this is baseline I think we we&#39;re good with baseline where it starts to come up this is your P it comes to a peak and then it comes back down so no this is not a normal P because remember it&#39;s peaked it&#39;s not smooth but your P comes back down and when it goes below baseline right here that is your Q wave guys okay where it goes below baseline this is your Q wave okay so following your Q wave you have your R wave so when you&#39;re looking at your R wave remember it&#39;s the first positive deflection that follows the P wave so let&#39;s look right here let&#39;s start over again okay because we definitely need the practice this is baseline this is where it starts to come up and so this is the beginning of your P okay you keep following your P you see how it&#39;s going back to baseline right here okay so it&#39;s back at baseline right where my little arrow is it&#39;s that layer just disappeared okay it&#39;s it&#39;s baseline right here okay and then you see where it starts to go downward because remember your Q wave is your first negative deflection meaning it&#39;s going to be below baseline so if baseline is right here then this right here is your Q where it had where it shows it okay so then what you&#39;re going to see is you&#39;re going to have a positive deflection so this positive deflection this is your R wave okay and our waves typically guys when you&#39;re looking at EKGs they&#39;re pretty easy to pick out because they&#39;re usually the tallest the tallest wave in the cardiac cycle so they&#39;re they are pretty easy to follow out so you just look at your R wave and then it&#39;s going to come back down to baseline and then we&#39;re going to follow it up with an S wave so your s-wave is the negative wave form that follows the are so again let&#39;s practice this is our P this is the beginning of our P here&#39;s our P our P comes back to baseline right here okay follow it over this is baseline up you see where it starts to come down well that right there that is the beginning of your Q and then where it goes back to baseline that starts your R okay you follow it up this all this whole thing right here is your is your R okay so you follow it up and then you see when it is at baseline then what happens is it goes below baseline and once it goes below baseline down here this is your s so the reason I take each one of those apart is because typically when you read it you read it as a QRS so let&#39;s let&#39;s practice on these remember your cure s is follow normally a p-wave so baseline here is your P wave you see it goes up it comes back down to baseline okay you see where it starts to go below baseline this is your Q and then it comes up this is your R and then it goes back to baseline and then when it goes below baseline guys that&#39;s your s that is your cure s complex and so when you&#39;re looking at your QRS complex some things you need to realize is that a normal range for a cure s complex is point zero six two point ten seconds so it shouldn&#39;t be more than three small boxes remember that the Cure s it represents the spread of electrical impulses through the atria okay so the reason I always like to tell you that is when we&#39;re reading strips if you know if you&#39;re looking at your QRS and you&#39;re curious is abnormal or it doesn&#39;t something&#39;s not right with it well then you know you got an issue somewhere and your ventricles if you&#39;re looking at a strip and you look at these P waves and there&#39;s something going on with your P waves remember I told you that p-waves represent depolarization of the atria and you know something&#39;s wrong with your atria so that&#39;s just I would like to throw that out there when you are reading strips those are two things that you really want to keep in mind as I told you you&#39;re curious you have a Q and R and an S wave so again let&#39;s go back I gave you normal nice pretty QRS okay so I got up throw some abnormals in there okay or it just wouldn&#39;t be nursing so an abnormal Kuras is anything that is less than point zero four so less than one small box or greater than point one zero so that&#39;s your so no more than three small boxes so that&#39;s your range if it is less than or greater than then we consider it abnormal and so that&#39;s what you want to realize when you see these so abnormal qrs&#39;s they let you know that something&#39;s going on in the ventricle and so you would need to do a little bit further investigation here so then let&#39;s talk about our T wave so your T wave represents ventricular repolarization so this is kind of where your heart is resting it&#39;s getting ready to start going again so this is where your heart is most vulnerable to any type of extra stimuli so you got to be careful about that guys when you&#39;re looking at your T wave and you&#39;re wanting to figure out well where where is my T wave the best thing that you want to do is it follows your cure s and it&#39;s a positive deflection following the return to baseline for your QRS so look right here and let&#39;s go through the whole cycle again this is baseline right here okay you see where it starts to come up this is the beginning of your P okay it comes back to baseline right here this is the end of your P this is baseline and you see where it starts to go down that right there that is the beginning your cue okay and so here is your cue it starts to here&#39;s baseline it comes up it comes to baseline and this is your are okay when it goes below baseline you&#39;re at your s and then it goes it when it comes back over here we&#39;re looking to where it goes back to baseline and then your first positive deflection following that where it starts coming up again this right here is your T wave okay so guys all of this right here this is like this is a cardiac cycle so remember a normal T wave is slightly slightly asymmetric I like to think about T waves if you&#39;re compare them because I always have students say well my P waves and mighty ways oh I can&#39;t tell a difference so two points that would help you with that one when you&#39;re looking at P waves they should look like little hilltops they should be symmetrical on each side kind of nice nice and smooth and round but your T waves they&#39;re slightly asymmetrical so I think about them as mountaintops you&#39;re having to climb up one side to get to the top so one side is going to look a little off than the other one at for example here are your here&#39;s some normals right here these first ones that my arrows are circling right here okay so this right here this is your T and then here is your P so look at that you see how it&#39;s slightly asymmetrical when it comes up same thing right here it&#39;s slightly asymmetrical okay so those are some those are just my tips really for how do you tell a P wave from a t way the other thing is remember look at your cure s complex this is your R this is always the easiest thing to find as your R well you know if it&#39;s before the QRS complex it&#39;s your P if it&#39;s after like right here where my arrow is it&#39;s your T so those are two tips to try and try to help you get it straight in your head so we look at T waves a lot if we have inverted T waves like we see here okay these are inverted T waves we are very concerned about that because that shows us or that lets us know there&#39;s been some type of myocardial ischemia okay so we get really worried about worried about that and the reason that is is remember that your heart is made up of cells cells need oxygen to survive and when someone has ischemia they&#39;re not getting the oxygen they need to be able to function so we worry about inverted ones but then you know what we don&#39;t really want these tall peaked ones that you see here also when you see really tall Pete remember it comes up to a point like this one right here when you see these then what I always want you to think about is oh my goodness what is there potassium level because typically you will see these in people that have very high potassium levels so these are just some abnormals that you&#39;re going to come into contact with when you are in practice I always like to make mention of a you wave you probably will not see a you wave too often and we don&#39;t know that much about you waves we think and I put it on here we think it&#39;s actually the repolarization of some of the fibers in the heart but we&#39;re not positive what we do know is we see you waves most often and people that have a very slow rate because they&#39;re easier to see because they&#39;re very small as I told you usually they&#39;re less than a third the size of a tea wave and so also realized some people have you waves and it doesn&#39;t mean anything however what you as a nurse should realize is that if you see a you wave a lot of times it means that patient has low potassium level and so what you would want to do is you and want to get an order to check their potassium level if they haven&#39;t hang on recently or you go look at their potassium level let&#39;s say if they&#39;ve had one that day and see if it&#39;s within normal limits so it&#39;s just kind of one of those if you see one you really need to go and look and if you see one and it looks abnormal it looks larger then you&#39;re t-wave you really want to be thinking what&#39;s this person&#39;s potassium level let me let me check it out so that&#39;s why I always like to mention it okay so it&#39;s not always a tried-and-true meaning that person&#39;s going to have a Troi imbalances but if you see one it&#39;s always best to be safe and let&#39;s look at their labs let&#39;s get something ordered here are some example of you waves so as you see right here this is a really slow it&#39;s real pretty but it&#39;s a really slow right so these you waves are very easy to see and I have them highlighted in red right here so I always like to start at the top so this right here this is baseline okay this where it starts to come up this is the beginning of your P you follow it around till it comes back to baseline that&#39;s the end of your P guys okay and so Aaron atheria and so what you&#39;re going to do is you&#39;re going to where it goes below baseline that&#39;s the beginning of your Q right here it comes back to baseline and then it comes up this is your R guys it stays your R until it comes back to baseline here&#39;s baseline and then oh look it drops okay so this is your s and then what happens is it comes back to baseline right about here okay so you follow it you see where it starts to go up this is the beginning of your to you eight and it comes back to baseline this is the end and then look it&#39;s just this extra little wave you have right here that follows your T wave okay and this is called au wave so when you see a u wave you better go check their potassium level and see what it is so I talked about waves now I want to go back and pick up with some intervals and I know this seems really overwhelming now but it will make sense when I start to put everything together and just realize you&#39;re not going to get this all at one time so you need to take little breaks and come back and make sure that you understand this before you go forward so that you don&#39;t mess yourself up and get confused so a PR interval it represents the beginning of the HR depolarization - beginning of the ventricular depolarization so when we measure a PR interval we measure it from the beginning of the P wave to the beginning of the Q our complex okay so I&#39;ve highlighted it right here for you so when you&#39;re looking right here again this is baseline okay this right here this is the beginning of the P you follow it all the way around okay you&#39;re back at baseline guys now you keep following it and when it goes below baseline that right there is the beginning of your curious complex so this is what you would measure right here so essentially what that&#39;s telling us that PR interval is telling us how long it takes for the impulse to get from the atria to the ventricle this PR interval is telling us that okay it should be between point one two and point two and point two zero so no more than five small boxes some things that can call cause a abnormal PR interval if it&#39;s too long it could be because they have something called a first degree block which we will learn about that shortly or they could have digitoxin e that can also cause a prolonged PR interval so I talked about PR interval let&#39;s talk about s T interval so s T interval looks at or I should say it represents the end of the ventricular depolarization to the beginning of ventricular repolarization so we measure s T interval from the end of the S wave to the beginning of the T wave okay your normal range should be no more than point zero four seconds okay so remember what is zero point four seconds is okay no more than it should be no more than one box okay so when you&#39;re looking at this right here the reason we look at that&#39;s the interval is because this s T interval if it has if it&#39;s abnormal okay meaning this s CM s the interval if it&#39;s elevated meaning really a payer or if it&#39;s the Pres meaning less less than R down down below here of greater than two millimeters well that tells us that that person has some type of myocardial ischemia and or injury you see that often in people who are having or have had an mi so that&#39;s one reason when someone comes in with chest pain we always look at the ST segment and see kind of what&#39;s going on so ST segment and then also your t way those are our two big ones that we look at when we suspect that someone&#39;s having an mi so guys this is this is everything we just covered we covered the P the QRS the T so let&#39;s kind of do a little recap in a little review this is baseline where it starts to come up that&#39;s the beginning of your P you follow it around till it comes down that&#39;s the end of your P okay then what you want to look at right here this you follow your baseline your Q starts where it starts to deviate down because remember your Q is negative so it&#39;s negative here and then here&#39;s baseline when it starts to come up see where it&#39;s starting to come up this is your R right here okay and then when it deviates down below baseline that&#39;s your s and then it comes back to baseline here baseline and then when it starts to come up this is the beginning of your T and when it returns to baseline that is the in D or T so guys this is kind of everything we just covered and so you need to go back and review again that chapter in your book that talks about cardiac dysrhythmias it goes into each one of these and it breaks it down so that&#39;s a great resource for y&#39;all to use for this section

Transcript for:Cardiac Conduction System and Basics of EKG

Transcript for:
Cardiac Conduction System and Basics of EKG