Electrical artifacts – or measured cardiac potentials that are not related to electrical activity of the heart – can mimic a wide range of arrhythmias and are seen in 100% of patients on telemetry. In this video, Dr. Joshua Cooper, Director, Cardiac Electrophysiology, Temple University Hospital, reviews various ways to identify and correctly diagnose artifact, which is critically important to avoid unnecessary testing and treatment.
Please also see Dr. Cooper's other two "telemetry tips" videos, including:
Telemetry Tips: Atrial Flutter and Atrial Tachycardia
Telemetry Tips: Mobitz 1 Block vs. Mobitz 2 Block
Telemetry Tips: Sinus Node Dysfunction
This is Dr Joshua Cooper and this is my third video in this series on reading telemetry strips. This one is an electrical artifact. I find this one particularly important because artifact is so prevalent and it is critical to distinguish artifact from true arrhythmias. As you will see, many patients in a hospital setting are connected to cardiac telemetry. The purpose of telemetry is to provide a continuous recording of what the heart rhythm is doing throughout the time that the patient is connected. This is accomplished by affixing small electrodes to the skin of the torso. Each electrode is connected via a wire to a battery powered transmitter that sends signals from the body to the central telemetry system. This system is designed to amplify small little electrical signals from the heart just like an EKG machine does and record the heart's rhythm continuously throughout the time that the patient is connected. One of the problems that can result from being continuously connected to telemetry is if there is movement in the electrical wires that itself can generate very similar small electrical signals that can compete and obscure the heart's rhythm presenting as electrical artifact. Another problem is if an electrode becomes disconnected from the patient or is in poor contact, that can also create a different type of artifact, including complete loss of the heart's electrical recording. When electrode becomes disconnected from the skin or a wire becomes disconnected from an electrode, a very characteristic artifact is created that is a large square wave that is squared off at the top or bottom because it goes well beyond and is clipped beyond each channel. And then it will gradually drift back to baseline. If connection is reestablished, then the heart's rhythm will be seen once again. But if the electrode remains disconnected, then you will see a flat line in the leads that rely on that particular electrode for that recording. Here's an example of a patient that had intermittent disconnection and reconnection of contact between an electrode and the skin which presented as periods of asystole or pauses that were not real. The way you can tell that these pauses are not real is that each one of them is preceded by this very characteristic square wave, followed by a sloping drift back toward baseline and then the heart's rhythm reappears. Another cause of electrical artifact can be electrical or mechanical devices that are inside the body, close to the body or connected to the body, such that the signals that they generate can be picked up by the cardiac telemetry system. For example, a patient with a left ventricular assist device or LVAD in place will generate electrical signals with high frequency that will absolutely be picked up by the cardiac telemetry. Those electrical artifactual signals will differ in amplitude depending on which lead you're looking at. And in some cases can completely obscure the QR S complexes as in the third channel displayed here or the QR S complexes may be greater in size than the artifact itself. And you can still see them throughout the tracing even while the artifact is present. Here's one of my favorite artifacts that I saw. When I was in training, there was a patient who had a bizarre type of artifact seen on telemetry. And we couldn't figure out what it was until we walked into the patient room and noticed that their telemetry box was propped up against the landline telephone that was sitting in bed with the patient. Every time in this case, the telephone rang, a very high frequency signal was generated artifact on the telemetry strip that lasted just as long as each ring of the telephone. This is because of a small little electromagnet that is located in the phone itself that controlled the ringing of the bell. So how important is it to detect artifact and recognize it on cardiac telemetry? What percentage of patients actually have artifact impacting their telemetry recordings? I decided to look at this when I was on service and took a random sampling of patients that we saw in consultation. I started by looking at the general floors, the medical unit, the cardiology unit, the heart failure, hospitalist and neurology units. And found examples in every single patient that we saw of electrical artifact. And then I went on to the IC US including the burn unit, the cardiac unit, the emergency room, the medical respiratory and neurosurgical units. And again, every single patient had artifact at some point on their cardiac telemetry. Basically, no patient remains motionless in bed throughout the time that they are connected. And 100% of patients on cardiac telemetry will have some type of artifact show up at some point during the telemetry recordings. It's therefore very critical to be able to pick up artifact and differentiate it from true arrhythmias because it will occur in every single patient. You see it is also so important to recognize that artifact can mimic virtually every type of cardiac rhythm being able to differentiate artifact from true arrhythmias will prevent unnecessary testing and treatment can artifact mimic S V T. Absolutely. It can here shown in red dots are the true QR S complexes in this patient. And all of the other signals represent artifact can artifact look like metamorphic V T. Of course, it can the red dots here show sinus rhythm marching through and the other deflections that look like V T are actually artifact. And the same goes for polymorphic VT. Here's an example that looks like polymorphic VT but the red dots denote sinus rhythm and narrow QS complexes marching through the artifact can artifact look like V F? Sure enough here is what looks like ventricular fibrillation. But the red dots show that there is sinus rhythm marching through. We're going to review examples of these and show how to differentiate artifact from these true arrhythmias. Well, what about atrial arrhythmias? Can atrial fibrillation be mimicked by artifact? Yes, it can. In this example, there are sinus P waves where each red dot is positioned each one followed by a QR S complex and they march through at a very regular pattern. And the low amplitude artifact which obscures the P waves may initially appear like atrial fibrillation. Similarly, atrial flutter can be mimicked by artifact. And here again, with the red dots showing sinus beats, each one followed by a QR S and the other signals are electrical artifact and not atrial flutter. This is a really interesting example where QR S complexes can mimic P waves because they are of such small amplitude in this particular lead. But if you look really carefully other than the PV C in the center, you can see that each QR S complex is preceded by A P wave and followed by A T wave which suggests to us that these are in fact QR S complexes and not P waves. This last example on this page shows P waves that look like QS complexes and this isn't as much artifact as much as it demonstrates the limitation of cardiac telemetry in terms of the amount of information that it provides, which we'll review on the next slide here is an EKG of that particular patient. It's somebody with congenital heart disease, with tetra of low and severe, right atrial enlargement and right ventricular hypertrophy. When you do a 12 lead EKG, you see a lot of electrical information from 12 different perspectives. And when you look at this particular patient, you can see on some of the leads very clearly that the first signal in each pair is a P wave. And the second one is a QR S. But if you look in lead two, the P wave is tall and the QR S is not as tall and they look very similar to each other. But on the 12 lead EKG, you can certainly distinguish that one is a P wave and one is a QR S. The problem with telemetry is that you only have two or three or four of the 12 leads and they're not in standard positions. So because you have only a fraction of the information that a 12 lead EKG provides, sometimes you can get some misleading information because of that lack of data. The benefit of telemetry, of course is that you're seeing continuous rhythm recording throughout hours and days of a patient's hospitalization as opposed to just a 12th snapshot that a 12 lead EKG provides. So each one has unique advantages and disadvantages one very important principle in looking at artifacts on telemetry is that the artifact itself usually has different amplitudes in different telemetry leads. In this example, you can see electrical high frequency artifact in the 1st, 2nd and 4th leads. But in the third, it's virtually absent because either the electrodes that record that particular lead are unaffected or the artifact is isoelectric in that particular vector. But you can see very clearly that P waves and QR S complexes in that third lead. And if there were any confusion, you could always look at that lead to eliminate that confusion and see that this patient is in fact in sinus rhythm. One really important reason why it is important to recognize that artifact may be of different amplitudes and different leads is that by default, the telemetry does not always display all of the available electrodes. For example, in this patient, one of the alarms showed this event which could look like polymorphic ventricular techo cardia and it only recorded initially three of the four electrodes by default, if you click on that last lead. However, you can see that artifact is absent and you immediately can figure out that this is all electrical artifact and the patient is in sinus rhythm throughout. So it's important to use all of the available electrical data on a patient as you start to analyze a strip to figure out whether something represents an arrhythmia or not. Another type of data that may initially be hidden is the hemodynamic data, especially in a patient in the IC U or a patient who has a pulse oximeter hooked to their finger. This electrical rhythm here may initially look in these two displayed leads like ventricular fibrillation or polymorphic V T. But if you then go and look at the arterial waveform, you can see that there is a rock steady waveform throughout this strip because this patient remains in sinus rhythm throughout. And that's simply electrical artifact and not a ventricular arrhythmia. Similarly, if you look at this patient's pulse oximeter or plethysmography, you'll see again that there is a very steady regular pattern in the wave form suggesting that the patient is in sinus rhythm throughout. Use all the information you have when evaluating the electrical rhythm, especially if the patient has an arterial line or a pulse connected here is that example before, where we saw what looked like pauses in the heart's rhythm. And we figured that they were not because of the electrical artifact that preceded each one suggesting that there was an electrical disconnect event from one of the leads. But you could have come to the same conclusion that this was artifact. If you displayed the plethysmography tracing at the same time here, the pulse aim meter wave form shows a very steady rhythm throughout showing that there are absolutely no pauses or interruptions in the heart's rhythm. And here is another patient with a wide complex polymorphic electrical tracing in these two leads. If we add the blood pressure data in this patient who had an arterial line in place, we will see that this event is real. There is a complete loss of the pulse during this wide complex rhythm. And this is a true polymorphic V T event in this patient who is in the IC U what is mildly interesting. And this is a physiologic phenomenon is that each blood pressure waveform is slightly delayed from the electrical events. There's a slight electrical mechanical delay, that is a normal phenomenon. So you'll always see the blood pressure pulse and a slight offset and slightly later from each QR s. What is a little bit more interesting and not as intuitive is that when you look at the pulse ox tracing, at least in our IC U, the way our telemetry is programmed is it has an electrical delay that is programmed into the system. This is not physiologic. The pulse at the fingertip is not this delayed compared to the pulse in the arteries of the body. It is more simultaneous. But for some reason in our telemetry system and in many that, you'll see for some reason, the pulsar wave form is programmed to display at about a second and a half delay compared to the uh electrical tracing. I'm not sure why that is, but it's just important to recognize that fact, you could also see if this patient had not had an arterial line in place. There's a loss of the pulse wave form at the same time that this polymorphic V T event occurred again with that slight offset suggesting that this is a real arrhythmia. This is an absolutely fascinating EKG that demonstrates a really important physiologic principle. This comes from a case report which I'll share with you in a moment. You can see on the rhythm strip at the bottom of this EKG lead. One, that there are two different sets of signals marching through the EKG somewhat independently. The red arrows show these spiky narrow signals and the blue arrows show these sort of widened rounded signals. And again, they are traveling somewhat independently of each other. But at times on the EKG, they are very close together. And the natural question comes, how can a heart generate those two signals? They are only 110 milliseconds apart. And that would mean that the heart was going at 545 beats per minute for those two intervals. And that's physiologically impossible. The heart muscle has a refractory period and it absolutely cannot go that fast and generate two Q RSS that close together. And the reason why we're seeing those two signals close together on this particular EKG is that this patient has two hearts, not one. This is a case report from the New England Journal of a patient who had what's called a heterotopic heart transplant. That means that a donor heart was implanted, but the recipient heart, the native heart was not removed. So this patient had two hearts in their chest. And if you look at their EKG, you'll see that the sharp spiky narrow QR S complexes are from the new donor heart. On the more wide QR S complexes shown with the green dots are from the patient's native heart and they are electrically independent of each other even while there is some mechanical coupling, because the two hearts are connected to the same circulatory system. It's important to recognize though that when you see these two sets of signals so close together on several occasions, it is impossible for them to come from the same heart. And that's because in this case, this patient has two different hearts. They're both myocardial tissue but separate organs. But I guarantee that you will almost never see a patient who has two hearts. And so the physiologic principle that I wanted to make here is that a heart can only go so fast. The physiology of the myocardium is such that there is a refractory period, the A V node can only conduct so quickly. So if you see a telemetry strip where there are electrical signals that are so close together that it is impossible for a heart to make those signals in sequence, then they cannot all be real. Here are three electrical signals in this tracing and they cannot all come from the heart. The reason is the first two signals are 100 and 65 milliseconds apart. That would be a rate of 364 beats per minute. And the second two are even faster at 100 and 35 milliseconds, which would mean the heart was going at 444 beats per minute and they all look somewhat narrow. There's no way that the A V node could conduct that quickly or that the ventricular myocardium could recover that quickly in order to create three QR S complexes that close together. So the question then comes, what is real and what is artifact if you use your electronic or your physical calipers to measure the distance between the QR S complexes that you know for sure are real. You will see that the middle of these three signals marches out with all of the rest of the sinus QR S complexes. It is in fact that electrical signal that represents a true QR S complex and the other two adjacent ones are artifact. It's absolutely impossible for the heart to go that fast. It's notable that the artifact really does look like true narrow QR S complexes, but physiologically, it is impossible for that to be the case. So we can therefore conclude that those two represent artifact. And here is a strip where you see what looked like narrow QR S complexes traveling all the way through at an extreme rapid pace. That is super physiologic. There is no way that all of these electrical deflections could possibly represent cardiac activity because it is simply too fast. If you took calipers and looked at the more prominent, especially in the bottom lead electrical signals, those are in fact the true sinus QR S complexes that you can see on this strip and everything else in between those true QR S complexes must therefore be artifact. There's no question that a lot of those signals replicate a narrow QR S complex morphologically, but there's no way that the heart can do that. So if you can find true QR S complexes marching through, then everything else has to be artifact. One heart cannot be in two different rhythms at the same time. And if you can see sinus rhythm marching through the heart cannot simultaneously also be in ventricular fibrillation or ventricular tachycardia. It's simply not physiologically possible. The next trick that is really important to consider when you're looking at a strip that you may be unable to differentiate artifact from true arrhythmia is to go back to the beginning of where the section in question starts. If you look at the beginning of this strip on telemetry, you can say a ha. Now I can see what look like true QR S complexes. And if you take your calipers and say, I wonder if I can show that this sinus rhythm is continuing throughout the rest of the strip, you'll be able to identify where the true QR S complexes are located throughout this strip. Those are the true QR S complexes, sinus rhythm remains. And if that's true, the rest of this must be artifact because the heart cannot be in two different rhythms at once. Regardless of how real those other deflections may look, it's impossible for them to represent true cardiac activity. If you can show that sinus rhythm is occurring throughout. Here's another example where you may wonder where the real QR S complexes are located. And if you go back to the beginning of where the strip starts, and the artifact is of much smaller amplitude. At the beginning, you can locate the true QR S complexes and use your calipers to march through and find where the true heart rhythm beats are located. This is sinus rhythm marching throughout and therefore everything else must be artifact, however real, they may look again, it's impossible for the heart to be in two rhythms at once. And you've demonstrated that sinus rhythm is continuing using your calipers and where sinus rhythm is clearly visible before the artifact starts. And conversely, you can go to the end of a section where you're not sure if it's artifact or a true arrhythmia and see if you can find true QR S complexes. In this case, they're very obvious when the artifact terminates and you can use your calipers to march backwards into the artifact and find where the true QR S complexes lie and therefore conclude that sinus rhythm is occurring throughout this strip, which means that all the rest of it must be artifact. Here's another example, if you're not able to initially determine what is real and what is artifact and whether this is a true arrhythmia or not go to the end of it and see what that looks like. Here. We can find where the artifact is lower amplitude true QR S complexes. We can march them back into the artifact and we can therefore identify where true sinus rhythm. QR S complexes are located, which means that all the rest of this, even though it looks like V T, it's all artifact. Here's another example of a patient alert where the telemetry recorded what it said was ventricular tachycardia. And let's look at the termination of this event because it's hard to determine here whether they, in fact our sinus rhythm QR S complexes marching through or whether this may in fact be real V T. But if we go to the end of this recording, we're going to see this, we can certainly see narrow QR S complexes following this event. And if we zoom in and we march backward, we can see that there is a missing narrow QR S complex. If this was artifact, you would have expected sinus rhythm to be marching through throughout and where that question mark is located, there should be a narrow QR S but we're not seeing it. In addition, if we look at the P waves, we can see that the P wave at the left arm of this caliper uh is not conducted. If this were sinus rhythm marching through artifact, there should be no reason why that P wave should not conduct. Therefore, we must conclude that this is in fact, real ventricular tachycardia that uh has interfered with the conduction of that P wave that falls right at the end when V T terminated spontaneously. And that also explains why during that isoelectric segment where we normally should have seen a sinus rhythm uh beat occurring. It did not because that last V T beat interfered with conduction and sinus rhythm picked up only on the following beat. So this is real V T, there is no ability to march the narrow QR X complexes back. And that is a clue in this case that we're dealing with a true arrhythmia. When a patient is in atrial fibrillation, we can no longer use our calipers to march out regular QR S complexes before or after an arrhythmia or artifact. In question here. Our question is whether those three deflections in the middle represent nonsustained ventricular tachycardia or whether that's artifact, but we cannot march backwards from the end or from the beginning of this trip because the patient is in atrial fibrillation. So how can we figure this out? We can rely on a unique morphology of the QR S here in that middle lead, the QR S complexes have a very distinctive shape. And in fact, we can pick out that shape in the segment in question, those represent true QR S complexes even though we can't exactly march them out evenly with calipers. And we can therefore conclude if those are conducted QR S complexes from a fib, the rest of it must represent artifact, a basic principle that I've been hinting at that I'll articulate more clearly here is that if you have artifact of smaller amplitude and native QR S complexes of equal or larger amplitude, then you absolutely should be able to see the native beats marching through the artifact. Let's think of that principle. As we analyze this tracing here, we have wide complex signals traveling throughout the mid portion of this strip. And we want to know is this artifact or is this true nonsustained ventricular tachycardia? If you look at the native beats, they are of larger amplitude. And if you look at these wide complexes, they are in this top lead of smaller amplitude. And so you absolutely should be able to see native beats marching through if this were artifact, but we're not seeing that we don't see sinus beats and tall narrow complexes marching through. Therefore, what we're dealing with is true ventricular tachycardia because we don't see Sinus rhythm marching through. And so you may ask, well, what about this? Isn't that a native beat marching through here or what about this here. Well, if we're concluding that those wide complex beats are true, ventricular tacho cardia, and we know that you can't have two beats this close together. Physiologically speaking, that must mean there there is artifact, but those signals are the artifact and the wide complex beats marching through our actual ventricular tech cardia, there may be one capture beat, meaning one conducted beat in the middle here, which is yet another fact that supports the diagnosis of nonsustained ventricular techo cardia. In this example, here's an example on the bottom where you see a section in question whether this is true ventricular tachycardia or whether this represents artifact here, the QR S complexes that you can see are of similar or slightly smaller amplitude to these wider complex beats that we can see here shown in the second double headed arrow. But if you use your calipers and march through, you can see that sure enough you have narrow complex Q RSS that are marching through very regularly throughout the strip. Those represent sinus beats. They are clearly seen even though in this case, the artifact is of larger amplitude. But nonetheless, you can demonstrate sinus rhythm is occurring. And therefore, these wide complex beats are in fact artifact. Here are a couple more examples of how we can clearly diagnose artifact because physiologically the heart cannot possibly do the thing it looks like it's doing in this trip, which initially looks like some bizarre type of atrial flutter. If this were atrial activity, we'd have to say that the atria are starting out at a cycle length of 410 milliseconds, which is 100 and 46 beats per minute and accelerating in dramatic fashion down to a cycle length of 80 milliseconds, which is 750 beats per minute. The atrial muscle just like ventricular muscle has a certain refractory period and it is impossible for the atria in a monomorphic fashion to go at 750 beats per minute. And similarly, there's no rhythm we know of that would have this dramatic acceleration. Therefore, we can conclude that this is not atrial flutter, but in fact, is sinus rhythm where we see the regular narrow QR S complexes marching out and each one must be preceded by a P wave that is obscured by the large amplitude artifact. And similarly, in the ventricles here, we see what initially looked like narrow complex Q RSS. But in fact, the uh cycle length at the beginning is 400 milliseconds, which is 100 and 50 beats per minute. And through this strip, we accelerate to a cycle length of 180 milliseconds, which is 333 beats per minute. And there's no way that you can generate narrow complex Q RSS. Uh The A V node cannot conduct that quickly. The ventricular myocardium cannot be depolarized that quickly. And in fact, there is sinus rhythm if you look very carefully on this bottom strip marching through here. And this is all artifact. I believe this artifact is created by one of the electrodes coming loose from the skin and gaining and losing contact with the skin, creating this artifact. Um that happens to be accelerating just by the nature of the adhesion and the proximity to the skin. But there's no way physiologically that this could be real and therefore, it must be artifact. Once again, here's an example of complexes that look very, very much like narrow QR S complexes. But they are so close together between 131 150 milliseconds, which would mean that the A V node would have to conduct at 400 to 462 beats per minute, which is physiologically impossible. And therefore, even if you can't find what are the real QR S complexes here, you know that all of these deflections cannot possibly represent the heart. And therefore, this is artifact. Another principle in diagnosing artifact comes from the fact that if there is something that is altering the electrical recordings artifact, meaning the wires are moving, the electrodes are coming loose or something of that sort, the artifact will often have different amplitude in different locations of the strip. So for example, in this right hand part of the strip where we're not sure perhaps whether this represents a true wide complex arrhythmia or artifact, if we can look at the left hand part of the strip and we say, well, we know that's artifact because we can see true QR S complexes there. That is just one more clue that suggests there may be something that's not quite right about the electrical recording at this time. And you can see different types of artifact adjacent to one another. It may not be always the case. But certainly if you see artifact in part of a strip, you should have a high index of suspicion that a mystery component of the strip may also be representing artifact. Here's another example of that. Uh There are several principles here on the left hand side, certainly with the middle strip there showing very little artifact and true. QR S is marching through. That's a clue right there. But let's say we didn't have that lead too and we only had the top and bottom strips there. You might say, well, I'm not sure if that's artifact or real. Number one, you can say, well, they're so close together physiologically that has to be artifact. But another clue is that you see different types of artifacts on the right hand part that is more clearly artifact because of the rate and the visible QR S complexes that are of larger amplitude than the artifact. And you can say, OK, there's something going on with the recording and if it's artifact on the right, it's very likely artifact on the left. But there are a number of clues here that tell you that none of this uh rapid activity is real. Let's go through some practice examples. And let's start with this one, which is actually a fairly straightforward one. Here, we have uh relatively rapid but not too rapid uh deflections that could represent QR S complexes. And one of the things you might say is, well, you just mentioned that if you see artifact in one part of the recording, then maybe that means that there's artifact in other parts of the recording. Well, the good news here is that this patient was in an IC U setting and had an arterial line present. And so we're gonna use one of the first principles we discussed, which is to use all the information at our disposal. And if we look at the blood pressure recording, we can see that there is a wave form for each of these deflections. This is real and this is extremely rapid atrial fibrillation with some beats that are uh you know, approaching and surpassing 200 beats per minute. But we know that this is real because in fact, there is a pressure wave form for every deflection and there are no other uh QR S complexes that are marching through. Of course, this section here in the middle represents artifact for sure. Um But the rest of this is is real. Here's another example, a little bit harder this time where we look at this strip and we wonder whether this patient is in atrial flutter or atrial fibrillation. You can see from the bottom that the telemetry thought this was ventricular tachycardia. But we can make out that there are narrow QR S complexes occurring throughout, especially in the bottom of these four strips. Um But we wonder whether this patient is in atrial flutter or atrial fibrillation. We're going to use another principle that we discussed, which is to go to the end of this event. And that's on the next slide. And we can see here that this patient is, in fact, in sinus rhythm, we can see clearly P waves and narrow Qs complexes and we can march them back all the way into the artifact. And we can show that those Qs complexes march all the way through and with a very similar interval between them. Therefore, we can conclude that this is artifact, there's sinus rhythm marching through because our calipers will demonstrate that regular narrow Qs complex. Even if we can't see the P waves during the artifact, we can infer that there must be P waves before each Qs because the rate and the intervals are exactly the same during the period of artifact as they are after the artifact terminates. Here is another practice example. And I would put this also in the medium difficulty category. You can see that the telemetry thought we were dealing with ventricular tachycardia. And the first thing that jumps out at me is seeing these sort of spiky wide bizarre complexes marching through at a particular rate. But if you look at all three leads, realizing that they're overlapping a little bit, but you have to look at each one independently. You can see that in the top of the three leads, you don't have a heart rate that is at that same rate as in the middle lead. You see a P wave, a QR S and A T wave that are occurring at about half the rate. Uh So that would suggest that these deflections are artifactual. They just happen to be really small artifact in the top lead. So they don't obscure the sinus rhythm as much in the bottom tracing. You again, see a P wave and a QR S and A T wave there. And the artifact is sort of of medium amplitude that it partially but not completely obscures the sinus rhythm marching through this artifact was created interestingly by an ICD programmer. This patient was getting their ICD interrogated at the time and the programming one was positioned right near where the telemetry box was. And there was some cross talk and some electrical artifact that bled into the telemetry system during this device interrogation. But you can see most clearly in the top of these three leads that there's sinus rhythm occurring. And therefore the patient cannot simultaneously be in a another rhythm that's twice as fast that represents artifact. And let's do one more practice. And I would say this one falls into the difficult category um because it's very challenging to distinguish um whether this is a true rapid S V T or whether there is artifact and superimposed sinus rhythm marching through. So let me just think it through out loud. The first thing that strikes me when I look at this tracing is that there are areas where there are two deflections that are just simply too close to each other to both be real. These two, there's no way the heart can do both of those or both of these or both of these or both of these at the same time, it's just too fast to be physiologic. And therefore, I would say that probably of each of those pairs of signals, one may be real and the other may be artifact and the real ones should look similar to each other. So for example, in those first two pairs, I would say that this electrogram and this one look similar to each other, whereas this one and that one look kind of different from each other. So if those are potentially true QR S complexes, then I should be able to take my calipers and march backwards and find other complexes that look morphologically the same. And similarly moving forward, I should be able to find complexes that look the same. And I can recognizing of course, that when artifact is superimposed, it's going to deform them and make them look a little bit different. But when artifact falls next to it, then it will leave the native QR s looking unaltered. So I think those in green here represent true QR S complexes. And the other ones, even though they look very similar are all artifact. If I then migrate downward to the other lead, I'll see a similar phenomenon where I can march through electrogram that look similar to each other. And again, you can see that there are pairs of deflections that are just simply too close together to be able to physiologically occur. Just like in the top tracing, there's no way one of those two has to be artifactual. Same here. So if you want to find the ones that look similar to each other in that lead, you'd come to the same conclusion that those ones that I have highlighted are real and the other ones are artifactual. But if you want to nail it down, you can always scroll to the end of this event and see where you can find QR S complexes when the rhythm isn't looking this fast here. I've scrolled in telemetry to the end of that event and we can find what look like real Qs complexes. There's no question here that we're in sinus rhythm and you just take your calipers and March back right into this area. And you can see that is a real QR S and the adjacent ones here are too close and there are four of those artifacts. So we've proven this patient is in sinus rhythm throughout. And the rest of those deflections, even though they look very realistic, cannot possibly be real because the heart cannot be in two different rhythms at the same time. And you've demonstrated that sinus rhythm is occurring throughout because the same QR S morphology at the same interval is occurring and able to be marched out with your calipers. So let's review the points that I made during this presentation uh to summarize. First of all, make sure you use all available information, including any telemetry leads that are not by default displayed, find them, they may be hidden and make them show up and that may give you the answer you're looking for and similarly look at the blood pressure tracing the pulse or mem tracing because if you can show that sinus rhythm is occurring throughout, then the fast deflections that you're seeing can be conclusively diagnosed as artifact. Remember, the heart can only do one thing at a time and almost nobody has two hearts in their chest. So if you can prove that sinus rhythm is marching through a strip with faster deflections, there cannot simultaneously also be V T or ventricular fibrillation occurring at the same time. So prove sinus rhythm, then you can prove the rest of it is artifactual atrial muscle, the A V node and ventricular muscle have physiologic limits including certain refractory periods. So, if you see deflections that are occurring at super physiologic rates, there is no way that that can be real and therefore there must be artifact playing at least a partial role in what you're seeing. You should look for consistent P wave or QR S morphologic throughout a strip. If you find QR S morphologic that look the same as each other and that march out with calipers, you're probably dealing with sinus rhythm and any other varying cycle length or varying morphology. Deflections likely represent artifact. If you're marching through with calipers and somehow you miss a QR S, it may be that, that QR S is obscured or hidden or negated by artifact. And if you keep marching through and you pick up right where you left off, it may simply be that one of the QR S complexes is obscured by artifact and sinus rhythm is marching through nonetheless. And similarly, you should be using your calipers at the very beginning and at the very end of the strip, in question to March out, what you can determine are true QR S complexes before the, the mystery section. And if you can show that they migrate forward into the strip or backwards from the end of the strip, then you've now determined that the patient is in sinus rhythm and then any other deflections that are seen must represent artifact. If there's a telemetry alarm event, it often will show you only a little clipped short segment and it may not show the onset or the end of the event. So zoom out and go to the general telemetry itself and see if you can find that event in the timeline and find the beginning or the end, which may not have been captured or saved by the alarm event in the telemetry. And lastly, you should always assess the patient if their inflammatory suggests that there is a period of asystole or ventricular fibrillation that lasts several seconds or longer. But you go and see the patient and determine that at that time of that recording, the patient was awake and utterly asymptomatic. Then that can't possibly represent a life threatening arrhythmia. So use the clinical correlation of the patient's presence of symptoms or absence of symptoms to correlate with what you saw on telemetry and conclude that what looked like a life threatening rhythm could not possibly be. So, if the patient was awake and asymptomatic, I hope overall that this presentation was helpful, artifact is extremely prevalent on telemetry. So everyone who looks at telemetry should be very versed in being able to determine the difference between artifactual signals and true arrhythmias.
