Articles

The ECG Course – Sinus Rhythms

June 3, 2019



hello and welcome back to the ECG course this is chapter seven in this chapter we're going to talk about sinus rhythms okay we're going to quickly review again the electrical conduction system we talked before about this little guy right here in the right atrium that's called the SA node s a node or sinoatrial node and that's your pacemaker of life in most healthy individuals you know it sends out a signal 60 to 100 times per minute hopefully the rest of this Bachmann's bundle here and these internal pathways here will conduct that signal through cellular polarization okay and then it'll pause right about here this is called the AV node a V node right there it'll pause and it allowed the atrium to completely eject all of its blood because hopefully you're having atrial contraction into the ventricles and then that conduction will continue down through the AV Junction here into the bundle branches this is the right bundle branch this is the left bundle branch and then you have your little Purkinje fibers off of those and then you'll have ventricular depolarization we said atrial depolarization come from the P wave or I'm sorry the P wave is signifying atrial depolarization and the QRS complex lets us know about ventricular depolarization so let's use that information we know so a normal sinus rhythm you're going to see this rhythm very very often most people are in this rhythm every day and again the rate is 60 to 100 beats per minute 60 to 100 beats per minute because what we're saying with a normal sinus rhythm is that the pacemaker is the SA node so with a normal sinus rhythm your pacemaker is right here it's the SA node you haven't anything cause any issues you haven't had any ectopic foci causing a new pacemaker or anything like that you're just having your normal SA node causing the atrial depolarization and it's really an assumption you don't truly know that but all of these things have to be true you have to have a rate of 60 to 100 beats per minute for it to be a normal sinus rhythm it has to be regularly regular and again we know that by measuring the are our interval so you would take your calipers or a piece of paper and you draw a line on the first R wave and then another one on the next R wave and you would measure that out and make sure it stays consistent throughout the entire EKG you will have variations I mean this could get longer or shorter over time but if it happens from beat to beat then it's not regular your P waves must be present for it to be a sinus rhythm your p2 QRS ratio meaning for every P wave okay how many QRS is do you have in an easily one two one so you have a P wave here you have a QRS here P wave here QRS here one two one there's no extra P waves no extra QRS complexes alright that must be true for it to be a sinus rhythm your PR interval has to be normal your PR interval has to be normal now again the PR interval to be normal needs to be less than 200 milliseconds or 0.2 zero seconds which is one big box so you would look at the bold line box okay and you would try to start at the very beginning of the P wave this is the closest one we got here and you can see that this PR interval is well within limits the QRS width must be less than 120 milliseconds now for that to be true QRS complex needs to be narrower than three small boxes and this one is just at the edge of that limit if you look the QRS complex it begins at that key wave right there and ends at that ST segment right there and it is just at three boxes and width so all of those things need to be true for this to be considered a normal sinus rhythm our next arrhythmia we're going to talk about is what we call sinus arrhythmia now science arrhythmia typically means if you broke down the word that it's sinus it's coming from the SA node but it has no rhythm arrhythmia it has it's not rhythmic as in regular okay so the rate needs to be between 60 and 100 beats per minute okay 60 100 beats per minute this one the rate is 1 2 3 4 5 6 7 8 9 it's right at 90 beats per minute because this is a six second strip the rhythm varies with respiration okay as the patient breathes you have a variation in the actual rhythm the regularity of it the p-wave must be present okay and you should have a p-wave for every QRS complex no extra P waves no extra QRS complex every P wave has a QRS complex you can see that's true the P waves look different than they did before we have a period here QRS here that's a P wave that's QRS complex P wave QRS complex so it's one to one at the interval again it has to be a normal length and you're curious width also has to be normal which is less than three small boxes and you can see obviously this is very irregular if I did my little measurement here you would see that it's regular here to here but then you have a prolongation okay and then it'll come back down and then it'll continue in a pattern like that be a little irregular so that's the big difference a sinus arrhythmia is the same as a normal sinus rhythm except it's irregular the next arrhythmia we're going to talk about is sinus bradycardia and sinus bradycardia is the same as normal sinus rhythm except for the first rule the rate the rate is going to be less than 60 for a sinus bradycardia so if you look at all these rules we have a rate of less than 60 the rhythm is regularly regular just like a normal sinus rhythm the P wave is present your PD QRS ratio is one to one for every QRS complex you have a P wave and for every P wave you have a QRS your PR interval is normal alright you can see it's less than or shorter than 0.2 zero seconds and your QRS width should be normal okay which would be less than three small boxes or point 12 seconds or 120 milliseconds now just a quick side note on the QRS width okay don't concentrate on that alone to determine an arrhythmia we'll talk about that more later on when we start talking about something called aberrancy okay the next arrhythmia is sinus tachycardia now this is a lot like sinus bradycardia except for it's faster than 100 beats per minute so we said a normal sinus rhythm has to have a rate between 60 and 100 if it's less than 60 it would be a sinus bradycardia if it's faster than 100 it would be a sinus tachycardia okay so let's look over this the rate greater than 100 beats per minute if you look at this strip you've got 1 2 3 4 5 6 7 8 9 10 11 12 12 times 10 is 120 this would be about 120 beats per minute it's obviously faster than 100 all right your rhythm is regularly regular that is a very important aspect of this so you have to look at your QRS complexes and see that they map out okay see that they map out so it should be very regular and you'll notice your p2p interval is also going to be the same length and all of these sinus rhythms alright so P wave is present that has to be true you have to be able to identify P wave for it to be a sinus tachycardia your PQRS ratio is one to one your PR interval is normal just like a normal sinus rhythm and you fear us with should be narrow okay now just quick mention about treatment for these patients sinus bradycardia is okay these over here sinus bradycardia is are usually caused by vagal stimulus because your pacemaker is still the SA node the typical cause for this is an over stimulation of the vagus nerve which causes the heart rate to slow down alright so these patients typically respond very well to fluid and if needed if they're very symptomatic atropine sinus tachycardia is almost always caused by the compensatory mechanism within the body okay so when you see sinus tachycardia you got to think that maybe the patient has a decreased volume or their containers too big or for some reason they have a norepinephrine release a catecholamine release okay so never think that with a sinus tachycardia you have to immediately go to advanced treatments a lot of times the these can be treated very well with just fluids okay next arrhythmia now we're getting a little bit more advanced sinus pause sometimes called sinus arrest okay you'll see here that you have a normal sinus rhythm and all of a sudden you have this big break alright and where what they're showing here is where the P wave began and then where the next P wave should be alright and then where the P wave should follow after that and you'll notice that this P wave here falls outside of that rhythm so this sinus arrest okay actually broke the rhythm it came back but it it came outside of where it should if it came after okay so the rate will vary because of the sign is positive RS the rhythm is irregular again because of the break in the rhythm the P wave is present except for at the pause that's why it's a sinus arrest okay the PQRS ratio must be one to one if there's a P wave right here it is not considered a sinus pause or sinus rest your PR interval is still going to be normal and you hear us with should still be narrow this is very a very uncommon arrhythmia compared to the ones we've mentioned before your next one is a sinus block a sinus block and it's very similar to a sinus pause or arrest okay except it will maintain the rhythm okay so the peak that there you're going to have one dropped beat and then you your rhythm will come right back here's what I mean by that the next complex should have occurred at that X right there okay and you'll see that if I just take that r2r interval from over here the normal order our interval from this rhythm and I match it up to where that beat was missed it stays within the regularly regular rhythm it just missed a beat so this is different from a sinus arrest this is a sinus block something blocked at that atrial depolarization but it came back a sinus arrest is different for some reason with the sinus arrest the atria never to polarize this is being blocked the rate will vary because of the dropped beats the rhythm is regularly irregular it will have a pattern which is also different from a sinus arrest the P wave is present except for the draft dropped beat the PQRS ratio must be one to one again if you see extra P waves here it won't be a sinus block your PR interval is typically normal and the QRS width will be typically be narrow okay so the big indicator of this is that it is a regularly irregular arrhythmia it'll have some sort of pattern and you when you match this out when you March this out you'll see that it was just a single dropped beat and you have another one here and it doesn't always occur in this three-to-one ratio of three normal beats two one drop B they could vary so we're going to quickly review what we've gone over and we're going to try to identify these arrhythmias so let's take a look at this first arrhythmia and first let's identify the rate all right this is about a six second strip here so we've got one two three four five six seven eight nine and ten QRS complexes we're right at the hundred mark we notice we do have P waves okay if P waves that's a good sign of atrial depolarization we have QRS complexes that look narrow they're not wider than three small boxes are PR interval looks normal okay does not look prolonged which would be greater than one big box our rhythm is regular if we measure this out it's obviously regular okay same amount of space between these QRS complexes okay from everything we've identified we have a regular rhythm the rate is just at 100 it's not greater than 100 we have a P wave for every QRS complex our PR interval is normal and our QRS complex is narrow this is a normal sinus rhythm it's also sometimes called a regular sinus rhythm let's look at the next one okay again we see P waves now I want you to notice that these P waves look different they don't have a lot of voltage there okay they don't have as much voltage but it's still a P wave we do have QRS complexes and those look narrow although we can't see the small boxes I show you their narrow let's check for regularity see our RR interval and see if it's regular okay regular regular it stays pretty consistent throughout okay let's look at our rate of one two three four five six seven eight and nine it's just at 90 beats per minute okay and we have a p-wave for every QRS there's no extra P waves so from everything we've identified our rate is less than 100 it's greater than 60 it's at 90 we have a regular rhythm we have a P wave for every QRS complex with a normal PR interval and we have a narrow QRS complex this is also a normal sinus rhythm let's take a look at another one okay first let's look at the rate this time one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen this is close to 150 beats per minute now just knowing that alone we know it can't be a few things we already know we we know it can't be a sinus Brady we know it can't be a normal sinus what is it well do we see P waves now at first you might wonder if you see P waves but I will assure you that there are P waves right there okay right there now what might make it easiest to do is find the P waves that stand out the most so towards the end of this EKG I think that that one stands out pretty good and that one stands out pretty good and P waves will always March out so if you find the highest point of the P wave there and the highest point of P wave there you try to just March it out to find the next one you know that there's now a P wave probably hit in there and that will help you find those hidden P waves you see that there's one there at the bottom of that if I go this way I can see that there's one there and from that one I can see that there's one there and that artifact that squiggly line there is just artifact the P wave is still hidden they're okay but something's happening either the patient shivering or somebody's moving the wires causing that artifact and our rhythm is regularly regular we've already identified that by looking at the p-waves but we know how to do it by measuring the RR interval so it's regularly irregular okay our PR interval looks to be normal our QRS width is obviously narrow so from everything we've identified we have a rate greater than 100 we have a p-wave a normal PR interval there's only one p way for every QRS complex and that QRS complex is narrow this is a sinus tachycardia sinus tachycardia let's look at the next one I'm going to do this one a little quicker let's quickly identify the rate one two three four five six seven eight nine ten all right let's see if it's regular really quick here the measure here I'm going to continue that measurement out and it's pretty regular okay our P wave exists you can see one here here here here we have a normal PR interval we have one P wave for every QRS complex there's no extra P waves our PR interval is normal our QRS width is normal this is a normal sinus rhythm one two three four five six seven eight nine tenths right at 100 beats per minute normal sinus rhythm alright let's check out the next one here now this one looks a little little funky a little different let's see how we can quickly identify this one two three four five six seven QRS complexes on this six second strip has a rate of about 70 okay let's see if it's regular and obviously you could already tell from looking at it that there is an irregularity but everything is regular up until that point everything is regular up until that point and then we have it a regularity but what I want you to notice is that this space from here to here if I double that between here okay we'll go right back into our rhythm so what happened is right about here I'm gonna draw it in there right in there we've had a dropped beat so what do we call that before it's not a sinus arrest because this continues the rhythm we just had a single dropped beat and is continued it's a sinus block this is a sinus block all right let's look at the next one okay obviously our rate looks to be slow one two three 40 beats per minute okay so our rate is slow our rhythm is regular all right if I map those it should be a pretty consistent regular rhythm all right we have a p-wave for every QRS complex we have a normal PR interval it looks like it's getting on a long point but it's it's still normal if you look at this last one look at that last PR interval it's right on the line there and you can see that the QRS complex occurs before the next fold line our curettes QRS width is narrow this is a sinus bradycardia sinus bradycardia let's look at the next one all right this obviously is fast you can see it right off the get-go 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 QRS complexes okay this is right about the six second strip so this is close to 160 beats per minute okay is it regular that's very important especially with these tachycardia so identify if it's regular or not okay and it is it does march out it's also important to identify the p-wave with these and we do see a p-wave now it looks like it could be a notch T wave to you doesn't it but not G waves typically don't exist okay not CH P waves might exist but not not CH T waves so if you ever see that where it looks like it's a double hump that's typically a T wave and a P wave kind of going into each other so those are your P waves right there you have a normal PR interval a normal QRS width this is a sinus tachycardia there's only a single P wave for every QRS complex and we call that a sinus tachycardia let's take a look at this next one now again this one looks a little different it looks slow it's about 50 beats per minute okay and it's regular except we have this irregularity here and I want you to notice that even if I put a QRS complex in there okay even if I put a QRS complex right in there that this does not continue the normal rhythm all right this is called a sinus arrest sinus arrest all right now when we start getting into all the other different types of arrhythmias you're going to see that these are going to become harder to identify amongst everything else that you learn but just remember that there's no P wave there's no non-conductive P wave in here everything is missing and it does not continue the normal rhythm alright let's quickly look at the next one well this one's a little bit more difficult isn't it it looks fast right so let's see here it's 1 2 3 4 5 6 7 8 9 10 11 12 13 14 QRS complexes so it's pretty dang fast alright it looks to be regular let's try to take a look here it looks pretty regular but again it's important with these tachycardia is to identify regularity try to get this here okay yep it's pretty regular that's gonna stay persistent throughout are there P waves present well remember what I told you to when you see these notches on the T waves look at this T wave here see a little dip that's the beginning of the P wave starting at that dip and then then you have the end of the P wave alright here alright so those are P waves now the PR interval it's important to remember that the PR interval should not be prolonged but we can't really identify it too well here because the beginning of the P wave is hidden so there may be a prolonged PR interval we're not sure the QRS complex is narrow okay so for all intents purposes this can be called a sinus tachycardia now if the PR interval does end up being prolonged we would say it's a sinus tachycardia with a first degree heart block and we haven't talked about heart blocks yet so I don't want to confuse you too much so just keep that in the back of your brain until we start talking about those all right here's another one and I'm not going to go through all the steps I just want you to see that it's very fast it is very regular it's regularly regular there's a P wave for every QRS complex okay the QRS complex is narrow and the PR interval is normal that's a sinus tachycardia again moving along this next one it comes up here all right 1 2 3 4 5 6 7 8 9 10 11 12 it's fast it's narrow QRS complex you have a P wave there's no extra P waves your PR intervals normal and it's a regular rhythm it's also sinus tachycardia alright taking a look at this next when this one looks a little bit different okay it looks almost like it could be a normal sinus rhythm right you have a P wave in narrow QRS complex and normal PR interval you know except it's not staying regular so what do we call that sinus arrhythmia make sure you don't see any extra p-waves all right you only have one p-wave for every QRS complex and it's a regular it's a sinus arrhythmia if everything is the same as a sinus rhythm except for the regularity it's called sinus arrhythmia okay let's take a look at another EKG as soon as it pops up and here's another example where you have everything looks like a normal sinus rhythm it just looks irregular you'll notice that your heart our intervals are not staying consistent they are all over the place all right they change with the respiratory pattern here's another example of sinus arrhythmia all right take a look at another example here again this is science arrhythmia it just looks like a normal sinus rhythm except it's irregular it's not regular alright so we just call that sinus arrhythmia here's another quick example alright you have P waves QRS complex is no extra P waves all right you're pure interval stays consistent your QRS complex stays narrow it's called sinus arrhythmia and then just one final example I'm trying to show you as many examples as possible so you can see that this looks different on you know different patients it's not always going to look the same and that's a hard concept to grasp about EKGs that you don't have to look you know a normal sinus rhythm on one patient will look completely different than a normal sinus rhythm on another patient and that's just because there's all kinds of stuff at play there you have the way the leads are set up you have you know the size of the patient you have the voltage of the heart that a polarization that occurs all kinds of different things may change the way it looks and then you could be looking at it from different leads which could also change the way it looks so that was our very first chapter on actual EKG rhythms and of course we started with the normal ones and we moved a little bit into the abnormal next in the next chapter chapter eight we're going to talk about each real rhythms so if you want to go back if this was too much for you you can start going back by talking about the systematic approach in Chapter six okay if you're ready to move on to the next chapter click on that picture on the right and we'll move on to atrial rhythms and as always don't forget to subscribe to our Channel

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25 Comments

  • Reply Abby Mendez June 3, 2019 at 1:31 pm

    Gracias

  • Reply DCI Research June 3, 2019 at 1:31 pm

    Excellent presentation thank you.

  • Reply Jane Darlington June 3, 2019 at 1:31 pm

    you have answered more than 7 years of questioning my medical report in less than 30 minutes. Thank you

  • Reply Youjin Lee June 3, 2019 at 1:31 pm

    It was helpful to understand EKG rhythm.

  • Reply Ariel Tumulak June 3, 2019 at 1:31 pm

    What does it means》 [Vent.rate(bpm):72 and

    800 normal sinus rhythm?

  • Reply Ally A June 3, 2019 at 1:31 pm

    You are an angel. Thank you so much!!!!

  • Reply ahmad kharabsheh June 3, 2019 at 1:31 pm

    Minute 16:20 the HR is 60 and not 90, those are 8 seconds on that sheet not 6 so you dont multiply by 10, R-R is 5 boxes

  • Reply Saby Rodriguez June 3, 2019 at 1:31 pm

    Really go video, but the subtitle is blocking the view

  • Reply Seth Moldenhauer June 3, 2019 at 1:31 pm

    Enjoying these videos. Good refreshers. However, you keep using the 6-second method for the rate which, from my understanding, is for irregular rhythms. You should be using 1500/small boxes or estimating via large boxes. E.x. 1=300, 2=150, 3=100, 4=75, 5=60 etc.

  • Reply Michael Cook June 3, 2019 at 1:31 pm

    At 23:43 why not two sinus blocks? Looks like RR interval might be upheld if you add one more QRS complex.

  • Reply Jessel D1223 June 3, 2019 at 1:31 pm

    Wow! Thank you so much! This really helped me …. a lot! MOre power to you!

  • Reply Carlos del rio June 3, 2019 at 1:31 pm

    Thank you so much for all the work you have done. I understand all the sinus rhythms and I'm looking at your other videos. I'm starting third semester in nursing school and these videos are helping me a lot!

  • Reply Amy Britton June 3, 2019 at 1:31 pm

    I'm enjoying this series and learning SO much. Well done. Starting at 15:10, your paper changes to show 6 small boxes per tick mark (instead of the usual 5), (assuming one second between each tick mark?), so I'm not sure of the number of seconds in each small box. Hard to know the true rate with this different type of paper notation.

  • Reply Lilly 19 June 3, 2019 at 1:31 pm

    you are the best

  • Reply M Poduska June 3, 2019 at 1:31 pm

    THANK YOU this course is saving my life right now!

  • Reply Stemplar Saint June 3, 2019 at 1:31 pm

    Thanks for you work. Are you sure about the rate, how are you doing this. one box 0.2 = 300bpm then 175 then 150 100 and so on, alternatively 1500 divide by small boxes between R waves. I don't think your rates are correct. The rate at 16.02 is around 60Bpm.

  • Reply Marie E June 3, 2019 at 1:31 pm

    Is the second example, (around 16:20) really normal sinus rhythm? Looks like sinus bradycardia by the way we were taught to count (big boxes 300, 150, 75, 60, 50). I'd put the rate at 50, not 90. But I also don't know what I'm doing.

  • Reply Louis Mendoza June 3, 2019 at 1:31 pm

    if there are extra p waves in sinus block and arrest what rhythm would it be? 3 deg hb?

  • Reply C Youngblood June 3, 2019 at 1:31 pm

    I really appreciate you for taking out the time to post these type of videos. I feel as though I'm in class and learning more than what I was while actually in school from my instructor. May God bless you!

  • Reply Fltnurse11 June 3, 2019 at 1:31 pm

    How did you get those calipers in your PowerPoint?

  • Reply Roro Rona June 3, 2019 at 1:31 pm

    thank u a lot 🙂

  • Reply sarax43 June 3, 2019 at 1:31 pm

    14:47 this looks like sinus tach !

  • Reply vaconstruction June 3, 2019 at 1:31 pm

    You need to fix some of your strips. on some of them shows 8 sec and you are counting like 6 sec strip.

  • Reply SunnyDRN13 June 3, 2019 at 1:31 pm

    where do you get your caliper.
    Thanks for your assistance.
    Sunny.

  • Reply AU7924K June 3, 2019 at 1:31 pm

    Excellent ECG interpretation course. Thank You

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