foreign [Music] reviews YouTube channel I'm Dr Sharon and I am going to be talking today about Basics about EKG and this is NCLEX stuff that you need to know and if you have already had some EKG training this is stuff you already know but if you haven't then I do recommend watching this video and I'm going to be talking in other videos about other types of rhythms but today we're just going to be talking about the basics okay so I have my screen a little different than I usually do because I actually want to be able to have a PowerPoint up while I'm talking and I don't usually do that so all right so let me first talk about um the where the electrical impulse starts so the interesting thing about the EKG when you're looking at an EKG or at a Telemetry strip a Telemetry strip is just a single strip an EKG or 1280kg is where you look at all the you know you hook them up to all the different electrodes and you get that single page strip that prints out you get all these different leads and stuff right so if you're looking at that or you're looking at a Telemetry which is just the single strip that people are hooked up to kind of continuously what you're really looking at okay this this is important if you understand what you're looking at is you're looking at the movement of electrolytes across the cell membrane and we call that an electrical impulse we call it an electrical impulse because these electrolytes have positive and negative charges and that's a little bit hard to grasp like where does this electrical charge come from we don't know okay we don't know uh but we do know that if you put a a wire near one of these electrolytes you can get an upward deflection uh on a piece of paper because there's an actual electrical charge that comes from these electrolytes and so we call it an electrocardiogram because these are electrolytes that are moving across the cell membrane in the heart and this electrical impulse this electrical impulse has to start somewhere and in the normal healthy heart this electrical impulse starts in the sinus node okay it starts in the sinus node and the sinus node is a bundle of cells at the top of the heart it's the SA node sinoatrial node sinus node whatever you want to call it it's the it's that bundle of cells at the top of the heart and these cells have the ability to fire spontaneously and they're considered the pacemaker of the heart they set the pace of the heart so I want you to imagine say you're watching I don't know how much racing we have outside the U.S but in the U.S there's people who like to watch what's called NASCAR NASCAR is people racing their cars around a track a circle going around and around see who can who can win and we have a famous race NASCAR race called the Indianapolis 500 it's re it's raised in the race is held in Indianapolis Indiana and every year that's a famous race people so whoever wins it wins a ton of money well there's a ton of cars like like so many cars that start this race and you can't when you have like 50 cars starting the race you can't line them up at the starting line right like a track meet you can't start them up on the on the starting line because there's too many cars so what happens is they kind of they kind of bundle up together at the beginning of the start and they kind of you know there's cars like for a significant distance from the beginning to the end right so they have what they call a pace car and the pace car starts and the cars take off after the pace car and nobody can go faster than the pace car the pace car is setting the pace and in fact if you go around the pace car you're kicked out of the race you're not allowed to do that you have to go the same rate as the pace car and so there the pace car sets the pace until some point on the track I don't know what it is but at some point on the track the pace car leaves the track and then the cars can then go as fast as they want to they can now go at their own pace so that's what a pacemaker is a pacemaker sets the pace and the SA node sets the pace for the heart none of the other cells are allowed to fire any faster than the SA node so the SA node sets the pace and the pace that the essay node sets is a rate of 60 to 100 and that's why our heart rate typically is between 60 and 100 because the sinus node fires at that rate okay and when and when that fires the the sinus node fires you get this P wave right here that's when the sinus node fires and the electrical impulse travels through the Atria that's that firing of the SA node and then when it gets down here to the QRS that electrical impulse is moving through the ventricles and out into the purkinje fibers and you may say well how does it travel what does that mean traveling what it means and I'm going to talk a little bit about depolarization and repolarization in just a minute but what it means is that one cell so the SA node is a bundle of cells and when they fire sodium and potassium which are electrolytes sodium potassium switch places one go one leaves the cell and one goes inside the cell and when those leave and go inside the cell it causes the cell right next to it to depolarize and that depolarization so we have depolarization depolarization depolarization depolarization depolarization and it goes all these cells all go and they depolarize just that fast you know how fast they depolarize I'm talking about from the time it takes to go from the SA node out into the purkinje fibers do you know how long that takes less than half a second y'all it takes less than half a second for that electrical impulse to travel from the SA node out into the purkinje fibers and you know it has to travel that fast because if the heart is beating at a minimum of 60 beats a minute that means it has to travel in less than a second in order for it to to beat 60 times a minute right so it has to beat at least uh the slowest it beats is one time every second so of course it has to travel that fast in less than half a second because you got to give it a chance to rest and refill with blood right so it it fires it contracts it rests refills with blood and then it fires again so that that electrical impulse travels so fast through the heart and you have to be able to grasp that concept I think part of the reason people struggle with looking at these EKGs is they don't grasp the concept that this stuff is happening so fast it's hard to even understand what less than half a second is like what is that like I don't think in terms of less than half of a second right so we think in terms of minutes often we think in terms of hours we don't think in terms of fractions of a second and so these things are happening so fast and the sinus node y'all it's like the most reliable thing in our lives this thing fires 60 to 100 times a minute for a hundred years how old was the Queen of England Queen Elizabeth what one of the the greatest queens of England she lived to be held was she 92 93 94 something like that her heartbeat the sinus node fired 60 to 100 times a minute for all her life that's phenomenal that is one of the most reliable things that we have which is why we want people to be in sinus rhythm if the sinus note stops firing it's one of the most reliable things we have in our like life and if it stops firing that's bad that's not good we don't want that to happen okay so we want our patients to be in sinus rhythm okay so the P wave the P wave and I talked a little bit about this let me go back here I'll just erase all this stuff on the slide here so I just want to remind you the P wave is that first wave the QRS is the big wave that follows it and the T wave is that a little bit smaller wave that follows the cura so every time you see a p q r s t p q r s t p q r s t p q r s t okay that's that's the way those waves fall out okay the P wave represents atrial depolarization if you don't know these words you do need to know these words this is something a nurse should definitely know what these words mean the P wave is atrial depolarization the QRS is ventricular depolarization and the T wave is ventricular repolarization okay now what is depolarization and repolarization I guess I got to move my face out of the way here so you can see what it says depolarization is the movement of electrolytes across the cell membrane and repolarization is the movement of those electrolytes back to where they started okay so let's go on to the next slide here all right so normally let's say this is the cardiac cell here okay so this is the cardiac cell right here and in its resting state sodium is in its highest concentration outside the cell and potassium is in its highest concentration inside the cell and there's there's channels in the cell membrane see sodium and potassium can't just cross the cell membrane just willy-nilly okay if they feel like going across the cell membrane that ain't going to happen there's channels that it has to go through and those channels are closed most of the time so normally the sodium and the potassium can't go across those channels it can't go across those channels until it's depolarized and this SA node has the ability to spontaneously depolarize 60 to 100 times a minute did you know that the sinus node will continue to defire depolarize even when the person is brain dead as long as the sinus node is getting oxygen it'll continue to depolarize 60 to 100 times a minute even when the person is brain dead that's why when someone is brain dead they still have to be on the ventilator but their heart can keep beating because the sign that's how reliable the sinus node is and it has the ability to spontaneously depolarize it doesn't require anything in the outside to do it it just does it on its own okay and when it depolarizes okay this is depolarization so when it depolarizes what you see is you see sodium and potassium going across the cell membrane and they switch places that's depolarization because there's an electrical impulse associated with those electrolytes that's why we call them electrolytes because there's an electrical impulse associated with them when they cross the cell membrane because we have wires on the chest right we have a little gel so the gel is against the skin I guess I go over here where you can see it the gel is against the skin and then you have a wire hooked up to that and and that transmits that electrical impulse over to uh um a device that can record it and it'll show waves right you go oh man that's pretty cool somebody was really really smart some electrical engineer was super smart to be able to figure that out so that's depolarization now you've got to understand that the cell cannot depolarize again until it has repolarized everything has to move back into place so here we have a depolarized cell right the potassium is outside the sodium is inside but we've got to see that go back so repolarization is when the sodium and potassium go back to where they originally were and once it's repolarized then it can depolarize again so the P wave let me go back here the P wave is atrial depolarization the P wave is when the atrial cells the SA node fires in the atrial cells depolarize you have that movement the QRS is when the ventricles are depolarizing so they're actually Contracting and then the t is ventricular repolarization so let me show you this again so here we have atrial depolarize and then ventricles depolarize and then the ventricles repolarize and that's that T wave okay so the P represents atrial depolarization the cures represents ventricular depolarization and the T represents ventricular repolarization and if you find you know I'm saying those things kind of fast so if you need to go back and re-watch this do that because you really do need to understand it so here's the reality an upright P wave on the on the Strip an upright P wave means this is what it means the electrical impulse is being initiated in the sinus node so let's look at this strip because here we have a P wave here we have a P wave P wave P wave P P what's this other stuff well this is the QRS and this is the T okay this is a t this is a t so don't get the p and the T confused okay so don't get them confused so here we have an up right P wave so what does that mean it means it's a sinus rhythm Dr Sharon are you kidding me it's that easy it is that easy if you have an upright P wave you have a sinus rhythm let's look at a couple other examples all right now this happens to have two strips nevertheless uh this one has it's in two leads and so we always look at lead two and the top one is lead to I'm not sure what the bottom one is but here we have an upright P wave I'm going to circle my p waves do you know what the first thing you should do if you get a rhythm on the on the NCLEX if you get a rhythm on the NCLEX the first thing you should do is in your mind Circle all your p waves they're all upright if I have all upright p waves you know what I say to myself looking like a sinus rhythm to me looks like a sinus rhythm I'm going to make sure I got a couple other questions I can ask myself but I'm pretty sure this is a sinus rhythm and if it's a sinus rhythm that's a good thing that means the sinus node is setting the pace and that's exactly what we want so when you see a sinus rhythm and one of the answers says call the health care provider I go on why would I call the health care provider about a sinus rhythm now it may be a fast or slow sinus rhythm and so maybe I do need to do something but I it's not an emergency the sinus note is going I'm happy with that that's what's supposed to be happening okay let's look at another one now this looks a little bit faster doesn't it and that's why you have to say to yourself well where is the P you cannot confuse the p with the T okay don't confuse the p with the T and so in your head you have to circle the p waves right those are my p waves well where's the T this is the T this is the T this is the T this is the T right so as you go along you say well where's the p and I have look at that every single p is up right and I can see every single one of them so I have an upright P wave so do you know what I think I think this is some kind of a sinus rhythm that's what I think let's look at another one okay so again we're in lead two which is what I like I like to see uh lead two rhythms my guess is on the NCLEX they're pretty much going to be lead to rhythms I don't think they're going to give you anything else so let's look and see what we've got so I it's kind of flat but it's still upright so I have a P wave P wave P wave look at they're kind of flat but it doesn't matter but it's not of clinical significance to the nurse and certainly not of Cl of significance on the NCLEX okay what you need to say is is it upright you go well it's a little flat but it's still upright and if it's upright that means what it means it's a sinus rhythm okay so the next thing remember I said you say to yourself well I'm pretty sure it's a sinus rhythm I got some other things I can check out so let me um let me tell you the other thing you can check out what you want to say is well I'm pretty sure it's a sinus rhythm but let me make sure the QRS that's QRS is that second wave right I want to make sure it's narrow a narrow QRS means the electrical impulse is traveling quickly through the ventricles that's what it means and we want that electrical impulse to travel quickly fast through the electric through the ventricles because a wide QRS I need to get my pen open here a wide curious do you know what it means it means it's weak so remember the W goes with the w why QRS means weak contraction and I don't want a weak contraction because the ventricles are in charge of getting the blood out to the tissues right the ventricles move the blood out of the heart out to the tissues and I don't want a weak contraction so I don't want a wide cures I want a narrow QRS because that tells me it's a nice strong contraction so what does it mean to be a narrow curious it means it's two and a half small boxes if you've looked at that EKG paper the Telemetry paper you know there's a little teeny tiny boxes on there if you've never looked at it you next time you're in a hospital or someplace look at a patient's chart I guarantee you they're going to have an EKG in there somewhere look at the EKG paper and find those little small boxes each small box is Time Each small box represents a period of time and it represents .04 seconds that's four one hundredths of a second giving you just a chance to like comprehend that four one hundredths of a second four one hundredths of a second how that's not what is that I can't comprehend that I can't either I can't comprehend that either I'm just telling you each small box represents four one hundredths of a second so two and a half small boxes is 0.10 seconds which is one tenth of a second one tenth of a second remember I told you that the electrical impulse moves from the SA node out into the burkinje fibers in less than half a second remember I told you that did you know it actually travels from the middle of the heart to the purkinje fibers so through the ventricles you know how fast that electrical impulse travels just through the ventricles a tenth of a second or faster y'all that is fast this stuff is happening fast and if it starts to slow up it gets weaker and weaker and weaker so we want to see these electrical impulses travel quickly through the uh through through the Atria and through the ventricles we want that QRS to be narrow because that tells me it's going really fast through there so let's see what this means so if we're going to measure the QRS that means let's see if I can draw this here this right here is the Q the r and the S okay that's the QRS so we're essentially counting the number of boxes inside the QRS so let me see if I can make this you can actually see it here okay so what we have here is this is the beginning of the QRS and this is the end so this I always find a QRS that starts on a line okay it starts on a line and so this one starts on a line of these are the little boxes right so each each one of these little things is a little box and there's five little boxes in one big box this is a big box here and there's five little boxes in each big box so I find a QRS that starts on a line and I say well that's one box two boxes so the number of boxes within that QRS is two small boxes and each small box is 0.04 seconds that means my QRS is .08 because it's two boxes right and so two bot one box is 0.04 so two boxes is 0.08 so my QRS is 0.08 and I want it to be 0.10 or less and it is right so my QRS here is narrow it is narrow okay let's look at another one all right let's look at this one so again I'm going to find so again I'm going to find one that starts on a line and and these are a little bit less obvious they don't have this sharp edge so I'm just going to go with this one this one looks like it's starting on a line so how many small boxes are within the QRS so here's one and then this one ends before even the next small box so it kind of ends halfway be between boxes so I have one full box and one half a box so one full box is 0.04 but one half of a box is 0.02 so my QRS is 0.06 which is by definition narrow so I have narrow QRS and by the way I have an upright P wave so here I have an upright p and I have a narrow QRS do you know what this means it means I have a sinus Rhythm means my sinus node is the pacemaker of the heart and that's exactly what I want I want my sinus note to be the pacemaker of the heart this is a little bit less clear but I think you can still see it well enough so here I have my the P wave is over here and then I have my QRS and my t my P my QRS and my T my P my QRS and my T so the QRS starts on a line here and it looks like it ends on the line here so it's only one box that's 0.04 seconds that means that electrical impulse travel through the ventricles in four one hundredths of a second So that's fast so we've got an upright so we do have an upright p and I have a narrow QRS which means I have a sinus rhythm all right now I want to give you show you an example of what a wide QRS looks like okay wide QRS so here I have an upright p and then there's no P's here I don't see any P's and then I have an upright p and this is a narrow QRS and this is a narrow QRS and this is a narrow QRS and then I have these weird things here in the middle okay I have these weird things in the middle so it's this this is the QRS actually right here this is the QRS and this is the T down here and then I have a QRS and then a t and then a QRS and a t there's no P wave which means if there's no P wave this is these aren't sinus beats these are something else right they're not sinus beats and look how wide they are from the beginning of the QRS to the end of the QRS over here it's almost it's it's like four and a half to five boxes so this is almost 0.20 maybe 0.18 to 0.20 so this is a y to have a wide QRS with no P wave a wide QRS with no P wave a wide QRS with no P wave and then we go back to Upright P wave and narrow QRS so what are these now I'm going to talk about these in a different uh video but these just to let you know these are premature ventricular contractions they're PVCs premature ventricular contractions PVCs but I'll talk about those in another another lecture all right so here's just a few things to remind you of what we've talked about let me make this a little smaller so you can see when there is an upright P wave when there's an upright P wave followed by an air QRS it's always sinus rhythm that that's just that's just a fact it is now normal you can only call it normal sinus rhythm if the rate is between 60 and 100. you have to call it sinus bradycardia Brady means slow cardia Hearts low heart right bradycardia it's a sinus rhythm the sinus node is in control but it's slow so if that's if the rate is less than 60 and you say sinus tachycardia tachy means fast cardiac heart fast heart if the rate is between 101 and 140 and the reason we cut it off at 140 is because it's so fast you can't really see the P wave anymore and you don't know that it's a sinus rhythm but that's that's another we'll talk about that another time okay so let's talk about how we determine the rate because we have to know the rate all right I'm going to move me up here all right so remember each small box is 0.04 seconds I already told you that each big box which is four small boxes okay this is a big box right here so each big box which is five small boxes is 0.20 seconds so five large boxes is one second so here we have some lines so we have one big box two so this is point 20 seconds another Point 20 is point forty point sixty point eighty one second so one five big boxes is one second so one second five more boxes is two seconds five more boxes is three seconds five more boxes is four seconds five more boxes is five seconds and five more boxes is six seconds so if you count the number of QR QRS complexes which is ventricular contractions if you count the number of qrx complex is in six seconds and multiply it by 10 you get your 60 second rate so what is this is this is six seconds because we just figured that out right so this is one second two three four five six so this is six seconds so we're going to count the number of qrs's and multiply that by 10. so 1 2 3 4 5 6 7 8 9 10 11 12 13 14. so 14 times 10 equals 140 which means this is a sinus tachycardia and I know that because I have upright p waves and narrow qrs's and the rate is 140. now the reason I want you to know how to calculate the rate based on those seconds like that is because there's times on the NCLEX they're going to give you a six second strip but you may not know it's a six second strip unless you count boxes okay so you need to be able to do that and here we have these lines that help us with that but you're not going to have these lines on the NCLEX you're not going to have any of this right so you're going to have to be able to just count boxes and go well this is a six second strip which means I can just count the number of qrs's in this strip and multiply it by 10 and I will get my rate so I know because you might go I know it's sinus because I see an upright P wave in an error QRS but I don't know if it's tacky or Brady or normal and it's like asking you what this rhythm is right and one of the options is normal size Rhythm and one of the options is sign is bradycardia and you go I don't know so you have to be able to count it right so that's that's why I want you to know how to do that let's look at another one so here we have upright p waves and narrow qrs's so I know this is a sinus rhythm but what I don't know is if it's sinus normal sinus sinus attack or sinus Brady so I have let me count big boxes so one two three four five so that's one second one two three four five so that's my second second one two three four five that's three seconds one two three four five that's four seconds one two three four five that's five seconds one two three four five that's six seconds so this is a six second strip and you may go well I saw these hash marks up there that seems odd that there's these hash marks up there so there are hash marks on the strips when you print them like when you actually see them in clinical you're going to see those hash marks and those hash marks occur every three seconds so in real life you don't have to be counting this stuff because you've got those hash marks but you could get and then clicks Rhythm that doesn't have the hash marks on it and you have to be able to figure out how many seconds it is so you got to be able to figure that out even when there's no hash marks okay so if this is a six second strip one two three four five six seven eight nine ten eleven twelve thirteen so there's 13 qrs's 13 times 10 is 130 so my rate is 130 so this is actually a sinus attack cardia all right let's do one more so here we have here we don't I got rid of the hash marks there were hash marks on here I got rid of them so you so we'd have to count them okay all right so here we have we're like I don't know is this a second six second strip I don't know so I'm gonna go one oh sorry one two three four five so that's one second one two three four five that's two seconds one two three four five that's three seconds one two three four five that's four seconds one two three four five that's five seconds one two three four five that's six so it is a six second strip one two three four so I have uh four times ten equals forty so my rate is 40. I have upright p waves and I have narrow qrs's so this is a sinus bradycardia sinus bradycardia okay so just kind of a summary here okay so a summary upright P wave and narrow QRS means you have a sinus rhythm if there's no P wave it is not a sinus rhythm don't don't kid yourself don't go well it could be there's a narrow QRS fine there's a narrow QRS but if there's no P wave it's not a sinus rhythm do not label something without a P wave as a sinus rhythm because it's not okay has to be a P wave now another thing to remember is the first word of the Rhythm tells you where the electrical impulse is starting that's what the first word of the Rhythm tells you so sinus rhythms then sinus rhythms start in the sinus node so sinus rhythm sinus Brady sinus Tech it means they start in the sinus no that's why the first word of the rhythm is sinus atrial Rhythm starts somewhere in the Atria but not the sinus node like atrial fibrillation and atrial flutter and if you look at Google atrial fibrillation atrial flutter they don't have upright p waves that's not what they are they're not normal ones anyway they look completely different but they're atrial rhythms they do have a narrow QRS but the the P wave is not upright and ventricular rhythms start in the ventricles like ventricular tachycardia and ventricular fibrillation there's no P wave and the QRS is wide with a ventricular tachycardia and I will do separate um separate things on atrial rhythms and the ventricular rhythms okay so I hope this was helpful to you I know it's not always easy but you do have to be able to grasp these basic concepts before you can really start to understand some of the other rhythms so if you want to take a clement review the NCLEX reviews we've got some coming up I'm actually doing an online Clinic review in November go to clinicreviews.com to register and I'm going to be in Los Angeles the I don't remember the exact dates but in December I'm going to be live in person in Los Angeles and then I think it's the 16th 17th and 18th of December I'm going to be in Napa Valley Northern California so those will be up soon on our website that you can register for and I really hope I will get to see you there so have a great rest your day