Hi, welcome back to our cardiovascular nursing essentials. Today we're going to go over EKGs. I am Jenny Kennedy, Nurse by Training, VP of Care Transformation. These are my disclosures. So here's our objectives today. We're going to really focus on technique of EKG and then I want to point out some things that I want you to pay attention to in order to identify things that you might need to be concerned about. So we'll do an overview of that. Here's your readings and additional resources. I encourage you to watch this video. It is a little entertaining and it does help kind of confirm some of the rhythms. It's a little fun activity that will help you remember. So I encourage you to take a minute and watch that. So let's talk about technique because EKGs are very insightful in telling us what's going on within the heart. So the technique is important. So what an EKG is, is just to remind you, is it's recording the electrical pathway within the heart. So it's looking at depolarization, which is stimulation, and repolarization, which is the recovery. So that's electrical currents that cause the atrium and the ventricles to contract and relax. So if you remember our conduction system, we talked about this in one of our first modules. The electrical impulse starts in the SA or the sinoatrial node of the atrium, the right atrium. That signal travels down through the AV node, through the bundle of His, and to the right and left bundle branches. And that's where that, that's the pathway of a normal electrical system. So the EKG waveform has components that we're looking at that helps us identify what's going on. So we've got the P wave, which represents that atrial depolarization, the QRS, which is ventricular depolarization, the ST complex, which is a ventricular repolarization. And then that J point, which is between the end of the QRS and the ST segment. So these are all key points that we want to look at. So there's some important measurements that we want to pay attention to. So typically our EKGs are recorded on graph paper and they're divided into one millimeter grids, little squares, and one box equals 0.04 seconds. So those heavier lines, and we'll see in a moment, are 0.2 seconds. We're really looking at those intervals that are the R to R, the heart rate, which we can calculate based on the, the strip, the PR, the QRS, and the QT. When we look at our EKGs and hooking them up, the placement is very important. And I say this because it matters where we place our electrodes. So we have chest or pericordial electrodes. And those are the ones that you'll notice go between the intercostal bones. So we don't want to place them on the bone. We really want to make sure we're getting them in the spaces between. That's important so we don't pick up additional activity that can be conducted through the bones. So you can see the placement here. We typically start with V1, which is the only one on the right side of the sternum. And you can see it's the fourth intercostal space. The best way to find that is on the sternum. You can start at the notch here and go down until you feel the angle of Louie or a little bump. And when you're there, you're at the second intercostal space on a patient. So you can just feel with your fingers down two spaces and get to the fourth space. So that's where, you know, you've got V1 and V2. And then the rest of your leads, again, you, I know it can be kind of awkward, but you want to make sure you're feeling with your fingers to get them between the intercostal spaces. You don't necessarily have to go in order, but V4 is typically, I know we call it mid-clavicular. So you don't want to use the nipple really as a point, especially on women, because it can displace it. So you really want to try to go right in the middle of their clavicle. V6 is mid-axillary. So think right in the middle of their armpit. And then you've got your V3 and V5 in those intercostal spaces. The other limb leads are important because they show us different views. This is how we get those different planes. And the important thing to note on these is you really want to avoid bones, muscles. You want to try to get them on the fatty parts for the conduction to give you the best reading. So these go on the right and upper arms and then the right and left leg. And I really like to show this because sometimes it can be confusing in terms of what are we looking at? How does all of this come together? So it's important to note that the right leg lead is actually neutral. It's used for grounding and minimizing artifact. But the right arm, the left arm, and the left leg are recording the electrical activity of the heart in relation to themselves. And they correspond to the AVR, the AVL, and AVF leads, as well as one, two, and three. So this is how we get those six chest leads with six transverse leads, giving us 12 leads to look at in the conduction system of the heart. So again, this is just another way to look at it. And I like these visuals because I'm hoping that one of them will stick with you in terms of what you're looking at, which area in the heart you're looking at when you're reading these EKGs. So we get the question a lot, how is it 12 leads when we use 10 stickers? Well, it's because it's using different planes to give us those 12 perspectives that we see on an EKG tracing. This is one of my favorite ones because it kind of puts it in perspective. So if you think of those leads as cameras, it's going to show which part of the heart you're actually looking at. So you can see from your AVL, you're looking where what part of the heart you're looking at. And I encourage you to get familiar with these in the textbook because they'll really show you the areas of the heart and the associated coronaries that can give you some guidance on to if there's anything going on within the heart. So when we do EKGs, it's very easy to kind of do a haphazard job. And it's just, it's, you know, usually because we're in a time crunch where we're trying to do a lot of things, but the quality is really important. So just like vital signs, I urge you to educate your medical assistants and your teammates to make sure you're doing the skin prep properly, you know, making sure that the skin is clean, dry. Is there any hair that needs to be clipped? You know, things like that, that can prevent the leads from sticking. The application, it's important. Placement matters. So we just talked about that. So making sure you're really using, finding the best spots on the body to place those leads. And all of this does help to eliminate artifact. So we don't want those extra signals or activity that can interfere with our electrical reading on our EKG tracings. And then making sure that we're really trying to prevent that signal interference. So especially in the technology ages we're at, we can get some additional interferences from cell phones, devices, things of that nature. So when we're talking about skin prep, we want to make sure again, that it's clean, dry, that if it needs to be clipped, we're doing that, especially on men with hairy chest or arms, sometimes you can't get a good placement of the lead. And that can again, cause artifacts or problems with the reading. So there's oftentimes skin prep pads, almost like alcohol wipes. There's also texturizing pads that can help that connection. I know we don't usually use razors, more clippers, things that don't have those blades for infection reasons. And again, we just really want to reduce that extra artifact because that's any kind of activity that really distorts the waves or the tracing. So that can be from a person shivering, maybe they're cold, that can cause extra conduction. Again, the technology interferences, extra movement. So we want to minimize that as much as possible. To do that, we want to make sure we're trying to get our patient comfortable, make sure they're relaxed. Supine is obviously the preferred position, that skin prep, making sure the leads are adhered to the skin is really important. And then maximizing the distance from electrical cords, outlets, phones, things like that. So I know that EKG interpretation is really the scope of the provider, but I think it's important as cardiovascular nurses, that you're aware of what things might be needing to be prioritized and brought to a provider's attention. And so we're going to go through some of our EKG interpretation. So you have an understanding and a foundation that you can build on of what's normal and what's not normal. And when it's not normal, what's urgent versus not as urgent. So we want to take a systematic approach when we're looking at reading the EKG. First thing we're looking at is the rate. Is it fast, normal, or slow? So that gives us a lot of insight into what's going on with the patient. What's the rhythm? Is it regular or is it irregular? Do we have a P wave or not? That's a very important component to evaluate. Is there any kind of block which shows a delay in the conduction? So is there anything with the QRS? Is that complex lengthened? Is that something that's concerning? And then anytime you find something that you're like, that's not quite right, you want to see if that's something that's new or different for this patient. So it may not be, it may just be their baseline or their regular. Is this something that's really concerning and related to a reason that there could be a change in the EKG? So let's talk about rate. There's a couple of different ways you can determine the rate. Obviously we know how to check heart rate, but when you're looking at a 10 second strip, you can also assess it with the small block method, which is going to give you a rate. So this first box is 300. When you go to the next line, that's 150, 175, 60, and so on. So you can count down the blocks between your QRS complexes. The kind of quick and easy method would be just to count the number of QRS complexes within your 10 second strip. And that will give you an estimate of their rate. The second thing we talked about was their rhythm. Is that regular versus irregular? And the way we determine that is really looking at our QRS complexes. That's going to tell us if those are the same distance apart, regular. Irregular would be obviously not the same distance. We also need to assess that P wave. So if there are P waves, are they regular or not? And then their rate. So sinus we said is, or sinus we know is anything within 60 to a hundred beats per minute. If it's less than that, we call that bradycardia, less than 60. If it's more than a hundred, we call that tachycardia. So that's important to note as well. And again, we evaluate that P wave and what its relationship is to the QRS. This is going to be really key in a lot of our diagnosing because there needs to be a P with each QRS. So we'll talk about that in just a little bit. So some of our regular rhythms. So we've got our sinus rhythm and that originates from that SA node in the right atrium. So we're looking at things like sinus tachycardia. So maybe it's, it's originating from the SA node, everything's regular, but it's beating fast. So over a hundred beats per minute could be slow. So sinus bradycardia, maybe it's in the fifties or the forties. So, but this is a normal conduction pathway that starts from the SA node and goes into the Purkinje fibers of the ventricles to depolarize and contract. So this is something we, we tend to like to see. Atrial flutter is something that is regular, but it is not sinus. And the reason we know it's not is because we're looking at this rhythm. We see these kind of sawtooth ways, but we don't see any P waves. So the absence of P waves makes it not sinus. So this is our atrial flutter. So the key takeaway there is yes, it's regular, but it is not sinus. So this is not coming from that normal pathway. Other irregular rhythms are, we may have PACs, which are kind of those extra atrial beats. These come and it fires from the atria, but it does not result in a ventricular contraction. Typically it can be normal. We don't get too, too concerned. Sometimes it can be caused by stimulants like smoking, caffeine. It may be electrolyte or stress related. In this case, in the same thing with these PVCs, these are ventricular contractions or just kind of irritable sites within the ventricle that trigger an electrical current. So again, a lot of people have these, we don't get too, too concerned unless they, they increase in frequency. Again, these are just some extra beats. You can see here, we've got sinus rhythm, extra beat, sinus rhythm, extra PVC. So these are all, we call them sinus, but there are underlying extra beats within the electrical system. It is important that we're looking at previous history. So when we're looking at prior readings and comparing them, because it tells a story, especially if we're seeing changes. So this is a series of serial EKGs. And as you can see here is okay. That's, that's fine. We're, we're starting to see some changes here in the second lead. These are early stages of an infarction. And then here we have that true fire hat ST elevation that an infarction is, is coming or, or imminent. And then here we see our inverted T waves. So this is definitely myocardial injury. And remember, we define that as anything, ST elevation is anything greater than or equal to two millimeters. And again, it looks kind of like that fire hat. So this is classic ST elevated MI. So this is something we would be very concerned with and take immediate action. And you, you can tell based on your, your 12 lead EKG, if you think back to why I wanted you to look at those camera kind of positions in more detail is because these are all correlated to locations within the heart. So you're going to see changes in the lead that correlate basically to the location of the heart. So here we see these changes in V4 and V3. So we've, we note these ST elevation changes in these leads, and those are associated with the left main and the LAD, which are very important in feeding the heart with most of the blood supply. So again, it's just important that you're familiar with what areas of the heart correlate to the EKG leads. So you can get a sense of what part of the heart is being impacted. And some other sinus kind of rhythms that are abnormal or things we might be concerned about are supraventricular arrhythms. And when I say supraventricular, that means supra above the ventricle. So these are usually rapid arrhythmias that originate in the atria. So they're more than 100 beats per minute at rest. These are things like our sinus tach, atrial tachycardias, our fib and our flutter, and some other atrial rhythms. And really want to make sure we're understanding what the cause of this is. Typically, any kind of tachycardia is related to a trigger. Something is stimulating it to respond. So we often have to do some discovery work to figure out what's going on that's causing this kind of response. This is a paroxysmal supraventricular tachycardia. It may be a little bit hard to see, but you cannot really see a clear P wave. And that narrow complex really is indignant of SVT. And the narrow complex without the P waves can really show you that it's an atrial tachycardia. So these are things that we want to make sure we're trying to identify. I will say that sometimes it can be too fast to see if there's a P wave. So it can be a little bit tricky. And so that makes the diagnosis a little bit difficult sometimes. So a lot of times we just kind of say it's SVT, which is okay. But sometimes we do need to distinguish what that underlying rhythm is and being able to identify if there is a P wave or not. So there are a few ways you can try to do that. Looking for any kind of pause or break in the rhythm, looking right before that QRS or right after. Sometimes those P waves can move and compare it to an EKG if that patient's in sinus. And then again, we want to look for anything that is triggering the start or the stop if that's the case. So we want to make sure that we're identifying any triggers or factors because generally what happens is we want to treat that and that will help resolve the arrhythmia. Atrial fibrillation is the most common dysrhythmia. We see it commonly. It is a rapid disorganized atrial depolarization. So it's very irregular. That's the classic first thing we tend to think of if something is irregular is that atrial fibrillation. It can be rapid. The ventricular rate can vary. It could be controlled, which is when you think about a controlled rate, you can associate that with sinus rate. So 60 to 100. It could also be slow. So it doesn't necessarily have to be fast to be atrial fibrillation. We do get more concerned if it is above 100. We do like that rate to be more controlled in that normal heart rate range. And one of the key things is that there's a lack of P waves. You can't identify a clear P wave. And that's really based on the lack of the atrial activity. It's just chaotic. So it doesn't always fire from the SA node. There are other points of initiation of that electrical current firing. And that's why you don't have that consistent P wave. Your QRS, though, is typically normal. So you shouldn't really see much of a change in that QRS. So want to make sure we're catching this. And of course, the main thing is, again, looking back and comparing to previous history. And the main concern with AFib is risk of stroke. So we just want to make sure we're protecting that patient. Atrial flutter, very similar. The difference here is it's regular versus irregular. That atrial rate will vary. It's typically pretty fast. The ventricle, ventricular rate is dependent on that AV block. So it doesn't usually go faster than 180. It's hard. Your EKG machine or your leads may show kind of a regular rhythm. But you have to remember there's all these flutter waves in here. So that can throw the machine off. So you really want to look at when you're looking at your rate, your QRS complexes. The key kind of characteristic are these flutter waves. They're kind of sawtooth in pattern. And generally, we'll have like two or three flutter waves per QRS. So you may have a two to one, three to one ratio of flutter to flutter waves to QRS. So similar to atrial fibrillation, we want to make sure they're anti-coagulated. Risk and benefit is assessed. So again, just checking their history and is this new. Our ventricular tachycardia, obviously, this is something that can be very concerning. It's defined as a run of three or more PVCs, more than 100 beats per minute. So there are specific criteria to call something ventricular tachycardia. It is an AV dissociation. And if the ventricular rate is fast, it's going to be difficult to make that dissociation. Sometimes it's too hard to really see what's going on. We call sustained VT if it lasts more than 30 seconds. And you want to note if it's monomorphic or polymorphic. And monomorphic means that it's stemming from the same node in the ventricle. If it's polymorphic, it's coming from multiple. So here's an example. And it can kind of seem like it's a tachycardia because generally it's typically looks pretty regular, maybe just a little bit irregular. Your rate is generally not just above 100, but usually 150 or so. You're not going to be able to see any P waves. And really the main characteristic is that your QRS is very kind of wide and almost bizarre. So your QRS is going to be greater than that 0.12 that we expect to see. Obviously we just need to be alert because if somebody loses their pulse with this, they're not perfusing, they're not getting blood or oxygen to their body. And this is a shockable rhythm. We do, you know, sometimes if a patient is having VT, but they're alert and oriented, we may try some medications like beta blockers, amiodarone, things of that nature. But if you happen to have a patient that is hooked up, they're in the office in VT and they're talking to you, be prepared because they cannot sustain that for very long. Same with the ventricular fibrillation or V-fib. Again, you're going to see kind of a regular pattern, regular rhythm, a very fast ventricular rate. There's no P waves because there's no atrial activity. And it's just kind of chaotic, erratic kind of course or fine electrical activity. This too is a shockable rhythm per ACLS. And then we also have ventricular asystole, which is just the total absence of any kind of ventricular electrical activity. It is important to note we never go off of one lead for asystole. We do verify with two leads. And it's important to note that this is not shockable. So the best thing to do with asystole is to initiate CPR immediately and start an ACLS protocol. If you're not ACLS in your office, it would be initiate CPR and call 911. So with that, I'm going to conclude this week's module. I encourage you to dive deeper and get more comfortable and familiar with your EKG rhythms. It does take time. It takes experience. But over time, you will become an expert. Please don't hesitate to reach out at academy at medaxium.com with any questions. Thank you for your time.

EKG interpretation

electrocardiograms

heart rhythms

electrode placement

Jenny Kennedy

cardiac abnormalities