Pediatric cardiologist and imaging specialist Howard M. Rosenfeld, MD, FACC, makes the case for ditching “SVT” in favor of more meaningful terms, enhancing professional communication as well as the diagnostic process. Offering a rubric for narrow complex tachycardia (NCT), he illustrates his talk with EKG examples to help physicians better categorize arrhythmias and select appropriate treatment.
And I'm sort of asking you all to join me in a 26 year crusade that I've had trying to convince people that SPT probably is not the best term to be using to describe a lot of our patients. And so hopefully by the end of this lecture we have a little better understanding of the term SPT of narrow, complex tech cardia. Why it's important and how it affects your patients and how we, as pediatric cardiologists think about it. So why not the term SPT. Why is that a term that keeps me up at night? Well it's a waste basket term because it means many things to many people. So when you're speaking to a pediatric cardiologist or calling the emergency room are speaking to a family, everybody has a little different understanding of what that term means. Do we mean narrow complex tachycardia? Do we mean reentry tech cardio? Which is a form of narrow conflicts. Tacky cardia. Do we mean reentry tachycardia? Except for W. P. W. Because generally people call their W. P. W. Patients W. P. W. And then they call their other reentry tech cardio patients S. V. T. And there's this term paroxysmal svt which certainly in the adult world people use synonymous lee for with reentry tech cardio. But in general I found that it's just a medical term that's used by physicians and emergency room personnel when they have a baby whose hearts going fast and they want to use medical term. And SPT is a quick one that people use and frequently use incorrect. So to me S. V. T. Is like modern art it means something different to each person. And when you're calling a consultant or discussing things with a consultant, it's important that the terms we use uh mean the same things to each of us. So I would like to use a starting off point for um narrow complex tachycardia is um and if we're going to be treating patients with narrow complex tachycardia, I'd prefer if we just say that we have a patient with narrow complex tachycardia as opposed to calling this SPT. If you use the term narrow complex tachycardia and you're talking to me from your office or from the emergency room um I know a couple of things I know that you've gotten an E. K. G. And you're dealing with a patient who is in a narrow rhythm and that you don't know what kind of narrow rhythm it is. And so that's that's at least a starting port for a reasonable discussion between us. So I guess the next question is what's the Ben diagram between narrow complex tachycardia and super particular tech cardio? They're similar phrases, terms but they are not completely overlapping. So if we all remember that Venn diagram describes the intersection between two sets. So if this blue and blue circle represents people who like musicals and the purple circle represents people who like horror films than the intersection would represent serial killers. So our question is, what's the Ben diagram between narrow complex tachycardia and super ventricular tachycardia? Well, in order to understand that we need to figure out what makes something narrow. So an E. K. G. Is a graph of amplitude versus time. So if we're discussing something being narrow on an E. K. G, the basically saying that it's traveling quickly through the heart and taking up little time per Q. R. Restoration. So if we remember our electrical system in the heart, each each beat begins at the sinus node. D. Polarizes, the atrium, gives up R. P. Wave and then it's picked up by the A. B. Note. So for something to be narrow on an E. K. G. As far as the Q. R. S. Being narrow, it means that the electrical activity is traveling anti grade through the A. V. Node and using the specialist, his parking G system in order to transmit the electrical impulse down to the maya cardio. So narrow on the QRS means and a great conduction through the A. B. Note and the hispanic in the system. So in order to figure out our Ben diagram, we have to answer two questions. First are all things that are narrow. Super ventricular while super ventricular refers to something that's generated from the A. V. Node or above. And since we just decided that in order to be narrow, Something has to travel and a grade through the 8th note to the Maya Cardi. Um Then the answer. The first question is yes. All things that are narrow are by definition super ventricular and then the second question are all things that are super ventricular, narrow. And the answer to that is no, there's a small D. K. G. To the lower right there and that's uh demonstrates a wide complex tachycardia. But that's basically because the patient has an underlying bundle branch block. And so if someone has a baseline bundle branch block, then all of their rhythms are going to be wide regardless of where they are generated from. And so this patient is in sinus tachycardia but with a bundle branch block. So the answer to our second question. So all things that are super particular are not narrow. So are then diagram looks below which all of narrow, complex tachycardia is incorporated within super ventricular tachycardia. But there's some forms of super particular tech cardio SPT, that fall outside of the narrow range. So in in building our rubric and understanding how we're going to differentiate how we're going to discuss narrow complex tachycardia. In medicine, we generally separate diagnoses when they meet two criteria. First of all, we can separate them, & 2nd of all, we treat them differently based on how we're separating. And so a reasonable example of this is a patient who comes into the emergency room with renal disease. And we automatically in our minds separated into the critic versus necrotic. And that's because we can separate those by a urine protein and we treat these diagnoses differently. And so therefore that's a reasonable separation. So if we're going to develop a rubric to understand narrow complex tachycardia under, you know, again, based on my preference, we're not going to use the term SPT, which would be the broadest term, and we're going to decide how are we going to separate out our narrow complex cardio patients based on being able to separate them and treating them differently And for anybody but an electro physiologist meaning if you are uh general cardiologist or an emergency room doctor or pediatrician, you really need to, in your mind separate narrow complex tachycardia into one of two things. There's those narrow, complex tachycardia. Is that our reentry tech cardio and those are tech cardio, is that have an accessory pathway. And therefore the tachycardia is an A. V. Reciprocating tachycardia, meaning the electricity is traveling down one pathway in in some cases down the A. V. Node and then back up another pathway in this particular case, up the accessory pathway. So for every for every A there's A V. And for everybody there's an A. And so that's one form of narrow, complex tachycardia reentry. And then the other form we term as automatic tech guardia's an automatic technical ideas are just things above the 18 oxy the 89 or above that are firing off faster than they should. And so those are relatively easy to name. If you think about the things above the 80 note, not that can fire fast, there's the Sinus node. So the Sinus node firing fast, which is one form of automatic tech cardio. We call that Sinus Tech cardio something besides the sinus node which is kind of in that picture we have above that would be in a topic atrial tachycardia. Many things besides the Sinus node firing fast, that would be multifocal atrial tachycardia or the junction of the heart. Of the A. V. Note of the heart also called the junction. And if that firing fast by itself we call that functional topic tech cardio. So within automatic tech cardia there's the Sinus node. Something besides the Sinus node. Many things besides the Sinus node and the Aveeno Re entry Tech Guardia's. We separate into two types. There's Wolf Parkinson White which everybody learned in medical school and I think everybody is familiar with and then there's the other ones, the non Wolf Parkinson White re entry tech cardio, we're gonna have to name those. Um what I don't want people to be calling them, which is frequently what they're called right now is S. V. T. We want to be able to name the non W. P. W. Types of reentry tachycardia, something besides SPT because you can see in our rubric SPT is a very broad term and we're down further along in our understanding. So let's briefly just discuss where we have normal conduction through the heart and then we can get into W. P. W. A little bit. So normally the S. A. Node fires deep polarizes the atrium and gives us our P. Wave there on the E. K. G. And then the A. V. Note pauses Because the job of the 80 notice to pause And the pause in the 80 note is represented by the P. R. Interval. And then the A. V. Note fires. And through the hispanic in the system D polarizes the ventricle, giving us our Q. R. S. And then the ventricle re polarizes and that gives us our T. Wave. And so that goes to a normal single cycle of deep polarization W. P. W. So on the left hand side we see a normal pattern based on the conduction we just described in Wolf Parkinson White. The definition of Wolf Parkinson White is a patient who has an accessory pathway, meaning another pathway where electricity can travel between the atrium and the ventricle. And in the case of Wolf Parkinson White, the electricity can travel anti grade, meaning an electric signal can travel from the atrium to the ventricle. And so then we ask ourselves, well, how does that affect our E. K. G. Well, the S. A. Node fires. That's W. P. W. Is an an A. Grade conducting pathway. The S. A. Note fires and gives us our P. Wave. And then while the A. B. Note is pausing, you start getting slow and a great conduction through non hispanic Kinji cells. And so that's represented by a slow deep polarization or a slow up sloping directly after the P. Wave. Because the accessory pathway doesn't have a pause function. And then the A. V. Note fires normally D. Polarizing the remainder of the ventricle, giving us the rest of our QRS. And then we have re polarization. And so what we end up getting on arresting E. K. G. Is a P. Wave with a very short PR honorable and up sloping that we call a delta wave that represents the slow conduction, an A. Grade through the accessory pathway and then the remainder of the Q. R. S. So there are patients with W. P. W. Who have never had tacked cardia and never will have tech cardio. So tacky cardia is a uh as an aspect of wolf Parkinson white but it's not a requirement to have a diagnosis. The only thing that's required to carry a diagnosis of wolf Parkinson white is an A grade conduction through an accessory pathway. Let's switch over to tech cardia to mechanisms of reentry tachycardia now. And when we talk about accessory pathways, there are three different types. We just mentioned one type which is an anti grade conducting accessory pathway. The other two types are obviously retrograde conducting pathway or a pathway that can go both anterograde and retrograde. So since we define W. P. W. As anyone who has an A grade conduction through their accessory pathway, the first and the third types of pathways there meet the criteria for Wolf Parkinson White. This other group, the one that just have retrograde conduction. Those are our non W. P. W. Forms of reentry tech cardio. And so again, the question is, what are we going to call these non W. P. W. Forms of reentry tech cardio, We're not going to call them SPT. And so the correct term for these and you may see this in some of our cardiology notes is a europe, which is the uni directional retrograde accessory path. That makes sense because it's a uni directional retrograde accessory pathway. The residents always tell me that they're not going to remember this term and I asked them how they remember Wolf Parkinson White or W. P. W. Because they always do and it only has one less letter and it it doesn't mean anything. It's the names of some doctors that have been lost to history, whereas europe actually uh means what it is, which is uni directional retrograde accessory path. So the non Wolf Parkinson white forms of reentry tachycardia are represented by this group switching gears just slightly. You guys may have heard the term orthodontic tech cardio. Anti dramatic attack cardio and that basically describes the direction that the electricity is traveling around in a circle. So on the left hand side with with electricity traveling in the correct direction down the node, an A grade and then retrograde up the accessory pathway. Ortho means correct like the term orthopedics. And so if the electricity is traveling correctly through the node, we call that Ortho dramatic, reciprocating tachycardia. If the electricity is traveling in the opposite direction, meaning initially it's going down the accessory pathway and up the 80 node, then electricity is traveling in the incorrect direction through the A. B. Note. And we call that anti drama tech cardio again anti and greek meaning against. So those are the two types of reentry tech guardia's as far as mechanistic lee. Now we were describing narrow complex a narrow complex QRS. We said it was generated by an A grade conduction through the A. V. Node. So let's remember that. Now, looking over at R three Types of pathways, the question is which of them can sustain orthodontic tack cardio And obviously they need to have a retrograde conducting accessory pathway. So the lower too can have orthodontic tact cardio and as far as anti drama tech cardio you need to have an integrated conducting access to pathway. And so only W. P. W. Patients can manifest anti drama tech cardio. Why do we separate these two tech cardio is out well orthodontic since it uses the A. B. Note in the correct direction is going to be a narrow complex tachycardia. That's your sort of standard narrow complex tachycardia that presents to the emergency room is treated with the Dennis zine. Anti drama tech cardio because the tax cardio goes the wrong direction through the A. V. Node that's going to end up being a wide complex tachycardia. And so if you remember when we were talking about our Ben diagram of super particular cardio, there are some types of super ventricular tachycardia that are wide and anti drama tech cardio represents one of those types. I know that was a very busy slide. Um But understanding these basic mechanisms and directions is important in understanding how to evaluate your patient with tech cardio. So here we have a patient Who is in a narrow complex tachycardia. The QRS are narrow and the rate here is around 240 beats per minute. Looking at it, it's Maybe even closer to 300 beats per minute, little under. And the question is this patient presents in tech cardia, Can we figure out whether this is a W. PW patient who is in orthodontic tech cardia because it's narrow? Or is this your app patient who's in orthodontic tech cardia? Uh And then why or why not? Why can't or why can't we figure that out? Generally when I asked the residents of this question, they say, well I can't really tell you whether this is W. P. W. Or not because it's too fast. I can't see delta waves. And the correct answer is we really don't know whether this patient is a W. PW patient or not while they're in their tax cardia. But it's not because it's too fast to see the delta waves. The the answer is when you're in your tacky cardia, if it's a narrow complex tachycardia, Your your pathway, your electricity is traveling down the 80 node and up your accessory pathway in re entry form. And if if the electricity is traveling up the accessory pathway and delta waves are produced by electricity traveling from the atrium to the ventricle through the accessory pathway. Then when a patient is intact cardia, delta waves don't exist. Patients only have delta waves on their EKGs when they're in sinus rhythm you can't see adult a wave while they're intact cardia. And so a cardiologist is always interested in seeing this E. K. G. Obviously because it allows us to see the tech cardio and get a sense of what it is. But we also need an E. K. G. After the patient is converted out of their tacky cardia in order to see whether they have wolf Parkinson white or not. So this patient presents an attack cardio like this if we terminate the tacky cardia and this is their E. K. G. This is a normal E K. G. With a narrow QRS and no delta waves. So this patient does not have an anti grade conducting pathway, so it's not a wolf Parkinson white patient. So this would patient would be diagnosed as having a uni directional retrograde accessory pathway. On the other hand, if the resting E. K. G. After we terminated the tacky cardia looked like this where the P. R. Interval is short, there is an up sloping and a widening of the Q. R. S. We would say this patient meets the criteria for Wolf Parkinson White. And so that when we terminated them we can then make that diagnosis. So that's an important point that when a patient presents intact cardio, we really don't know whether they have Wolf Parkinson White or not. The diagnosis of wolf Parkinson white is based on their resting E. K. G. I think this is a patient who um lets us understand this a little bit and and it's a complicated patient. But if we go through it slowly kind of illustrates some of the things that we've been discussing. So this is a patient that presented to an outside emergency room and they were in what the outside emergency room terms. S. V. T. And they got some identity, seen a bunch of other medications. They eventually uh converted to a slower rhythm. And they were sent to our emergency room and I was called by the resident the emergency room who said Dr Rosenfeld we have a patient is in the emergency room who had been an SPT at an outside emergency room and now they're here in a slower rhythm. And we were wondering you could come down and console. So I came down and I asked him if I could see the E. K. G. Of the patients presenting tech cardia and it looked like this. So generally I would ask you guys what you thought about it. But in order to save time and not put people on the spot. The first thing that I noticed about to see kitty is that it is rapid and it is regular but it's not a narrow complex tachycardia. This is a wide complex tachycardia. So the initial concern would be ventricular tachycardia. But as I said, this could also be a Wolf Parkinson white patient who is presenting in a wide complex tachycardia because it's anti dramatic meaning. Its attack cardia that's going down there accessory pathway and up there a V notes. So it is a form would be a form of re entry cardiac. So in order to figure out exactly what was going on to this, the patient was now in a slower rhythm. I asked the resident what their rhythm looked like right now. And they said well it's normal. And so we walked into the room to see the rhythm on the monitor and the monitor rhythm look like this. That's the upper upper rhythm there. So that's kind of a funny looking rhythm. It's a widened rhythm and it's hard to know whether that little bump at the beginning of each complex is a P. Wave or whether the whole thing is a Q. R. S. If the little bump is a P. Wave, then it's possible that this represents some form of Wolf Parkinson white because it would be a short pr interval and a wide QRS. If the whole thing is a Q. R. S. Then it's possible that the patient had been in a rapid ventricular tachycardia at the outside hospital. And now with some medication on board they're in a slower ventricular rhythm but it's still ventricular and so I really couldn't tell from the C. K. G. But fortunately the outside hospital recorded an E. K. G. When they converted the patient from there rapid tech cardia to their slower rhythm. And that looked like this. So the first portion of that upper run is the patient in their wide complex tachycardia. And then the lower strip shows that funny rhythm we were just looking at. But if you look at the first three beats after the patient converts from a rapid rhythm to a slower rhythm, you can see that it looks more like a classic form of Wolf Parkinson White with a P. Wave that's a little generous and then a short and pr interval and an up sloping to the Q. R. S, which we would call a delta wave and a widening of the Q. R. S. So this patient that presented in a wide complex tachycardia was in fact Wolf Parkinson White patient who has a somewhat funny um QRS pattern in their resting kg. But right after converting with the dentist scene, we were able to demonstrate that they do have Wolf Parkinson white. So EKGs in the tachycardia are very important for the cardiologist to get. And if you have those you should always pass those on E. K. G. After we terminate the tacky cardia is important because it allows us to diagnose if the patient has wolf Parkinson white or not. And then it's frequently useful to have this E. K. G. Which is the termination itself because it can sometimes point out some subtle findings that allow us to make a better diagnosis. This is the patients resting 12 G kg, which again is a little atypical for wolf Parkinson white. But we made that diagnosis based on the prior strip. So we said we like to separate narrow, complex tachycardia into the re entry type and into the automatic type. And the question is clinically, how do we make that differentiation? Well, there are different presenting aspects to these two different types of tech card and it's important that we differentiate them because their management is very, very different. So first of all, if we see P waves then that can be helpful in reentry. Tachycardia is the P waves are being generated. Buy deep polarization of the atrium through the accessory pathway. And so the P waves will be retrograde meaning they'll be right after the QRS and they'll generally be inverted in the inferior leads because the atria is being d polarized from the ventricle instead of the other way around. Also, the distance between the our wave and the P wave is going to be shorter than the distance between the P wave and the next our wave, Automatic tax card is if we see p waves, they're going to be irregular and varied in shape because as we said, automatic tactic parties are generally generated by a portion of the atrium that's firing automatically separate from the sinus node. And I'll give you some examples of that in just a second reentry tachycardia is because they have an accessory pathway and a cycle length are extremely regular. So if we look at the rhythm strip, you should be able to take the left side of the rhythm strip, bring it over to the right side of the rhythm strip. And all of the QRS is should line up meaning the R. R interval. The distance between our waves should be fixed. Automatic tech guardians because they're being generated by something just firing willy nilly. There are less regular rhythm. The reentry tachycardia is also because they have a cycle length are at a fixed rate. So if somebody comes in on a monday to the emergency room With a narrow complex tachycardia at 210 beats per minute. And if we convert them with a dent, a zine and then they come back on friday. Their reentry tech cardio rate is still going to be 210 beats per minute because that's the cycle length of their tech cardiac automatic tech guardians, which are very often ah Mickley driven Varian rate. If a patient is federal or if they're upset or if they're human dynamics are not very good, their rates are going to be faster. So automatic tech cardio as rates will vary. Whereas reentry tech cardio rates are quite fixed. The reentry tachycardia start and stop suddenly. So the classic description of a reentry tachycardia patient will come into your office and they'll say I was sitting on my sofa and all of a sudden I felt a jump in my chest and then my heart was racing and racing and it lasted for 15 minutes and then I felt a little nauseated. I threw up and then I noticed that my tech cardio slowed or stopped. So reentry tachycardia has an abrupt initiation and an abrupt termination. Whereas automatic tech cardio tend to warm up and cool down. They start slower and then they speed up on their own unless they're treated. And then when we start to treat them, we basically put them to sleep. So reentry tachycardia as we terminate. Whereas automatic tech cardio as we suppress and the medications we use for them are therefore different. If we see a P A. C. Or a PVC during the tachycardia, we know it has to be an automatic tech cardio because reentry tech cardio is, as we said, our A. V. Reciprocating for every A. There's a. V. And for every V. There's an A. So you can't have an extra beat sort of thrown into the rhythm. So if you see an extra beat or an irregularity, it has to be an automatic form of tachycardia instead of a re entry form Dennis zine or vagal maneuvers classically break reentry tech cardio because we terminate the A. V. Reciprocating cycle using a denizen or vagal maneuvers on automatic tech guardia's won't break the tech cardio. It might pause it or slow it. But whatever automatic focus is firing away on its own isn't affected by the identity and the dancing works at the A. V. Node. And so if you have a an irritable focus up in the atrium either caused by scar or tumor or irritation from a virus, it's going to be firing off on its own whether or not it. Benzene is there or not? Oh sorry, slight pause. There we go. Finally. Cardioversion. So in the rare instance where we need to use cardioversion for to treat attack cardia, cardioversion will terminate a reentry tachycardia. Because if we break the cycle of reentry, the patients should go back into a regular rhythm. Cardioversion just pisses off automatic tech cardio. So if you have a patient who's in a multifocal tax cardio or a junction, a topic tech cardio and you try to cardioverter, cardioversion is a very often ah Mickley stimulating event. And since we said that automatic tactic RDS are very autonomously driven. You'll end up with a patient who's just in a faster automatic tech cardio. So cardioversion is good for reentry and bad for automatic tech cardio Just to briefly discuss Dennis Zine. So Dennis Zine is given by a rapid flush and hopefully a larger, I? V got a very short half life around 10 seconds. And so you need to be giving it in a vain. That's if possible closer to the heart. So an ant a cubicle vein is better than a peripheral smaller peripheral I. V. In the hand. And it has to be given with flush of relatively large amount of saline because you want to push it to the heart before it's gone. And denizen will transient lee blockade conduction. And so as we said it will terminate a re entry type of tachycardia but it will pause an automatic tachycardia. So while denizen is a treatment for reentry, it can be very useful diagnostically for automatic tech cardio. We can go into that a little bit later. That's the dozing in case it's basically 50 micrograms to 200 micrograms per kilogram. And it comes in a six mg vial. So as sort of an adult dose would be one vial of identity. So here's an example of a six year old who had an atrial septal defect closure. Previously who presents with 10 minutes of palpitation, pallor and nausea. You get an E. K. G. And it looks like this. So again, this to me is a wide complex tachycardia at a very rapid rate. It's again around 280 beats per minute. So again in our differential. The first thing I would think of as VT because any time you see a wide complex tachycardia, you should need to at least think about BT in this case. Uh It's possible the patient had prior atrial surgery. It's possible this represents some kind of an atrial tachycardia and it wouldn't be unreasonable to give a denizen. To see if we can figure out if we give a denizen and it terminates. Then it was a form of reentry tech cardio. If we give a dentist scene and it pauses or slows, then it would diagnose a different kind of tech cardio. So this patient was given a dentist scene and something sort of interesting happens here. Now we have the QRS is look more narrow than they did before and there's a flutter wave baseline. So it turns out that this patient came in actually in flutter With 1-1 conduction At almost 300 beats per minute. So if you're In 1-1 conduction, Then you're not going to see flutter waves. And what happened here is the identity scene has blocked the flutter from 1 to 1 conduction, 222, 1 conduction. And so we went from a rate of around 300 beats per minute to a rate of around 150 beats per minute. But now we can see the flutter waves and we can diagnose this patient having atrial flutter. This would be a not uncommon rhythm for a baby born uh with a heart rate of 300. If you have a newborn Who presents with a heart rate of 300 shortly after delivery. Um atrial flutter would be the most common rhythm to present after birth at that rate. And Dennis zine obviously won't convert flutter because the dentist who works at the A. B. Note and flutter is a micro circuit within the atrium. So this baby would need to be cardioverter. Here's another two month old with a rapid irregular rhythm. And so just looking at this the first thing I noticed that it's it's an irregular rhythm. And so by definition this can't be a reentry tachycardia. This has to be some form of automatic tech cardia. If I look in front of the QRS is I. C. P. Waves and I see at least three different morphology P waves here. So this is a very nice example of a multifocal atrial tachycardia. An automatic tachycardia where different focuses within the atrium are firing off independently. And so this patient would not respond to a dentist scene and needs to be put on some kind of medication too to suppress these extra sinus areas of electricity electrical activity. Here's a patient who's a two month old who had tetralogy of flow and had a trans annual repair and just comes back to the intensive care unit. Again, these are a little more sophisticated and not necessarily something you would see in your office. But the simple teaching point of this has been looking at this, I can immediately see that this is an irregular rhythm the while it's slightly regular. You can clearly see that there is some art are intervals that are shorter than other art R R intervals. So this can't be a reentry tech cardio and so therefore there is no way that cardioversion would be the appropriate management. Were this patient to be unstable? Dennis zine could be used in order to die diagnostically, but Dennis zine isn't going to convert this rhythm to a normal sinus rhythm because it's not re entry. And this ends up being a reasonably good example of a patient who is in junction, als topic tech cardio or jet, which again is a form of automatic tech cardia and not an uncommon rhythm that we see in our post operative tetralogy of fellow patients. Finally, if this is uh this would not be uncommon to be a strip that is brought in by an E. M. T. Or sent in by a pediatrician for a patient that presented to their clinic with fussiness and heart rate. That was too rapid account in the office. So looking at this rhythm strip, it's obviously not more than one lead, but it gives us quite a bit of information. So I can see that this is a narrow complex tachycardia. And if if I were to take the first half of the this rhythm strip and put it over top of the second half, all of those are to ours would line up. So this is a very regular rhythm. So my initial thought is that this would be some form of reentry tech, do you? And in an appropriate management to terminate, this would be a density. Here is the E. K. G. Of the patient once they hit the emergency room. And again you can see it's a very regular tax cardio again at about 300 beats per minute and narrow complex. And when we give a dent a zine and we record, we see the tacky cardia and then we see some wider beats and some pauses and then reinstitution of sinus rhythm at the end of that strip. So this is a good example of a response to a dentist scene of a patient in a reentry tech cardio. So getting back to our rubric, we've separated, we're not going to use the term SPT. We've divided our narrow complex tachycardia into the automatic forms and the re entry forms and we separated reentry in the W. P. W. And europe's. The question is why do we care whether a patient has W. PW versus europe? If we're going to treat them the same and they respond to a dentist scene, you know, why do we separate them? And the answer lies in the fact, how do patients look when they're in reentry tech cardio, generally in the emergency room, they look like this, They're a little scared, they're stable, they're watching TV and their heart rates 280 beats per minute and we give them a Dennis zine and they convert, we watched them for a little bit, we send them home. So it's really uncommon that a child will get sick or die from their reentry tech cardio. We know about it and we know how to treat it. The only Children that get sick, very sick from re entry tech cardio are babies who are presenting with their initial episode because frequently those Children will be home for two or three days. Their parents don't recognize the fact that their heart rate is very fast. They just know that child is not feeding well. Might be throwing up a little bit fussy and by the time they get very sick and they come into the emergency room that's when they have poor ventricular function. And we need to act quite quickly to treat those patients. But even those patients and we had one just a little while ago in our emergency room if treated promptly, they do quite well. But patients with Wolf Parkinson White dies suddenly. Um We had a patient here in Oakland who was a pitcher no diagnosis previously and he was on the pitching mound and he dropped dead fortunately they had a defibrillator on the sidelines and they defibrillate him and brought him to the hospital here. And as E. K. G. Showed a delta wave diagnosing the patient is having W. P. W. So since both WCW patients and your app patients have reentry tachycardia. And we've already said that branch attack cardiac rarely is a life threatening problem. Question is why do patients with Wolf Parkinson White have a risk for sudden death? And it must have something to do with the fact that Wolf Parkinson White patients have pathways that conduct an A. Grade. Because the only difference between WCW patients and are your app patients is the W. P. W. Patients can conduct from their atrium to their ventricles. I had atrial fibrillation when I was younger and I had it a bladed but I always ask the residents when I'm in a fib and my atrium is going 600 beats per minute, is generating 600 electrical signals per minute. Why is it that I just don't fibrillating? My vengeful doesn't fibrillating and die. And the answer is I have a functional aveeno Good. That the job of the A. B. Note. Excuse me. The job they have noticed pause and so even though my atrium is generating six or 800 electrical signals per minute, my ventricle responds At a slightly increased rate of 160 in an irregular irregular fashion. So the a. v. node acts like a revolving door at a nice hotel. It will allow people through if they're going if they're coming through in an organized fashion. But if a bunch of people run at the revolving door all at one time, they're only going to get through in an irregularly irregular fashion. Now if I had W. P. W. And you throw in an accessory pathway, then if I go into atrial fibrillation, The electrical activity has two ways to get to the ventricle either through the 80 node, which has a pause or through the accessory pathway which doesn't have a pause function. And so if I have Wolf Parkinson white and I have atrial fibrillation then I'm at high risk for my vegetables defibrillate, I would go into V. Fib and I would die. So W. P. W. Patient is more like this then someone with a revolving door. And so the reason why patients with wolf Parkinson White die suddenly is because atrial fibrillation is a not uncommon rhythm and it's more common in patients with W. P. W. And if a patient with wolf Parkinson White goes into atrial fibrillation then they can go into V. Fib and die. So that's where the mechanism of sudden death lies. And that's why it's important that we identify our wolf Parkinson white patients separate from our europe patients. And even those wolf Parkinson white patients who don't have clinical tacky cardia could have a suffered sudden death were they to go into atrial fibrillation? So W. P. W. And sudden death W. P. W. Is not uncommon in patients with congenital heart disease, It's, it accounts for about 0.3% especially patients with Epstein, since they have an abnormal Czechoslovakia analysts, they have a common incidence of Wolf Parkinson White. The risk of sudden death and childhood is unknown, but the occurrence of h even adults with W. PW is not uncommon. And so there has been an estimated lifetime risk For sudden death of about three or 4 for our Wolf Parkinson White Population. So finally the last differentiation is now that we're down to Wolf Parkinson White, we need to know which patients have rapidly conducting an A. Grade pathways and therefore at high risk for sudden death versus those that have slow risk pathways and our low risk for sudden death. And so that's something that we do in the cardiology division, We separated our patients into high and low risk with W. P. W. And we can do that either by doing electrophysiology testing and looking at the speed of their accessory pathway or by exercise stress testing the patients. If we get their heart rate up high enough and their delta wave goes away it means they don't have a very robust pathway. But if we exercise them and their delta wave persists then we need to take them to electrophysiology study and potentially oblate them if they have rapidly conducting. So I'm right about 10 minutes left in the talk and I've pretty much come out down to everything. The last issue is just a few medications that we try not to use in Wolf Parkinson white patients and those are predominantly to Jackson. Um The Jackson, while it's an excellent medication for our, you're at patients since it speeds conduction to the accessory pathway, it might actually take one of our lower risk wolf Parkinson white patients and make them into a higher risk Wolf Parkinson white patients. So if we have a patient that we know has Wolf Parkinson White, we avoid the Jackson is our first line therapy and generally would have the patient on a beta blocker. So let me just speed through here real quick. So in summary, getting a call from a resident or someone who says we have a patient in the emergency room with SPT and my attending asked me to call that that to me um simplifies the understanding of this diagnosis. What I call, I'd like to get. It is sorry for waking you up. But we have a patient who presented in a narrow complex tachycardia and the re KG showed that it was a regular narrow complex tachycardia. They were stable and they had a working I've and we felt this represented a reentry tachycardia. So we gave them a denizen and we recorded an E. K. G. In case you wanted to look at that and the patient converted to a normal sinus rhythm. We repeated their E. K. G. And they had a delta wave. So we made a diagnosis of wolf Parkinson white and we know not to give to Jackson. And so the patients on a beta blocker and we want to know when you would like to see them back in cardiology clinic. So that would kind of be a a fellow level discussion of a patient in the emergency room. But I think hopefully after this talk you at least all understand the steps in that discussion and why each one makes sense.
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