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EP Fellows Curriculum: Ventricular Tachycardia and ...
EP Fellows Curriculum: Ventricular Tachycardia and ...
EP Fellows Curriculum: Ventricular Tachycardia and Sudden Death in the Patient with Congenital Heart Disease
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Video Transcription
Thank you, Nishant. I feel honored to get to talk to you and everybody who's on there. I know you have put huge amounts of effort into making sure that there is a collaborative, thoughtful curriculum that's going out to electrophysiology fellows, and to be honest, I'm just glad to see pediatric and adult congenital topics on the list. It's something that makes me really excited, so I'm excited to get a chance to talk about it. I am going to briefly put the stop video partially because my office is relatively dark, but also because my feed will be better if I'm not also trying to put video out, but if for some reason or another you need to see whether or not I have eyebrows, feel free to let me know and I will put the video back on. I'm going to talk about ventricular tachycardia and sudden death in the patient with congenital heart disease, and my focus here is really going to be on adult congenital heart disease and for people who don't see a lot of congenital heart disease. Some of the slides that you're going to see here are going to be intended to give people an overview and to give people an introduction, and then what I would say is either as we get to the questions or as we get into individual lesions, if people have specific questions either about individual lesions or about a way of thinking that is more a drill down, stop me and let's talk. I know that this is not the best forum for that, but nonetheless, as we have started to move increasingly towards doing things online, we have to be aggressive about making sure that we're all getting the education we need out of the online session. So hang on here. So here's what I want people to get out of this talk. First of all, what is the traditional teaching? There's a lot of reasons to hold that in the back of your head, and then which lesions are high risk? And some of that is about which lesions are unexpectedly high risk, and the reason for that is because as you start to put together in your head an idea of which congenital heart disease lesions are worrisome in the adult world, some of the ones are ones that you wouldn't necessarily expect, and we're going to go into that in a little bit of detail. How have the causes of mortality changed over time? Clearly, we who are electrophysiologists or electrophysiologists in training are particularly focused on arrhythmia, but it's important to put that into perspective of what's the overall mortality in people who survive childhood heart disease? What are the risk factors that we need to pay attention to? And then finally, what therapies are important? And I think when we get to the end of the talk, what we'll have seen is there's been a progression in almost all of these, and we're going to try to progress through them together so that we end up with a good framework to treat individual patients. So traditional bradycardia, this is from a review by one of the foremost, if not the foremost cardiac electrophysiologists in the pediatric and adult congenital world. This was from 2002, so, you know, starting to be about 20 years ago. And the traditional teaching was that there was sinus node dysfunction. There was congenital AV block or AV block that occurred mostly because of congenital abnormalities, even if it was a little bit after birth, and then acquired AV block. And the sinus node dysfunctions were either people who had had an enormous amount of scar and patch in their heart, people who'd had mustard repairs or sending repairs, which is when you switch the atrium so that the blood that was coming in one side of the atrium is directed to the opposite AV valve. Fontans, where a large amount of surgery is done in the atrium to divert blood away from the heart and directly into the lungs. And then atrial scars and patches in general. And as we've learned, we've learned that some of these things are due to the suture lines and the long bypass times that these require. But the more we've started to learn about these lesions, some of these lesions that require substantial atrial surgery are also associated with other congenital and genetic risk factors that make sinus node dysfunction more common. The second is congenital AV block. And congenital AV block can either be because you develop AV block at the time you're a that does happen, but also people who have abnormal conduction systems in which either their repair or even the interventions at the time of their repair, like catheterization or like ablation, can cause you to have complete AV block. And those are endocardial cushion defects, people who have congenitally corrected transposition. And I put in here the segmental anatomy SLL, but for those of you who get deeply interested in how congenital heart disease patients actually result, that's not the only one of these anatomies that that happens in. It's just the most common. And then single ventricle patients, people who are having those Fontan or single ventricle operations that I've talked about. And then finally, there's acquired AV block. And by and large, when I say acquired AV block, what I mean is post-surgical block, unlike the true adult population where people get acquired AV block after coronary artery disease or after a major ischemic event, this is people for whom the act of operating on its own causes AV block. And VSD closure and tetralogy of flow are the most common here, but anything that ends up working in the area of that endocardial cushion or in that outflow tract area, repairs on the aortic valve, any kind of myectomy that involves the outflow tract can easily end up with acquired AV block as well. And then traditional tachycardia is obviously the other side of that. And there are two important lesions that are associated with Wolff-Parkinson-White syndrome or ventricular pre-excitation. One is Epstein anomaly of the tricuspid valve. The second is that same current congenitally corrected transposition that I told you about. There are other lesions as well, but these are the two that should really jump out to you. So much so, and we'll talk about this a little later in the presentation, that it is a primary thing you should be looking for, even in a congenital heart disease, as you think about people that are at risk for tachycardia if they have these lesions. And then intraatrial reentrant tachycardia is the other glove that goes with the bradycardia that's due to long and complex atrial surgeries. So those same operations that I mentioned on the last slide, that same idea of atrial scar and patches in general affecting the bradycardia side of things, also predispose people to have intraatrial reentrant tachycardias, which by and large, people mean macro reentrant circuits that use a previous scar or a previous patch as the central obstacle, and then rotate in a macro reentrant fashion around that patch and require intervention either with antiarrhythmics or with ablation or with a surgical maze procedure to eliminate the substrate in the atrium for macro reentrant tachycardia. Atrial fibrillation is relatively common in congenital heart disease when compared with other young people, mitral valve disease, aortic stenosis, single ventricle patients, and I'm not going to spend a lot of time talking about that, partially because adult practitioners have a lot of familiarity with atrial fibrillation and understand a lot of the resources to deal with it, and partially because the people who end up with atrial fibrillation are highly likely to be the same people you would suspect it in, which is people that have elevated left atrial pressure and one way or the other mitral valve disease. Ventricular tachycardia is where we're going to spend a lot of our time today, and I just want to say right up at the front that the data, the information that we have, is overwhelmingly in Tetralogy of Flow, which I'm going to abbreviate as TOF very frequently in this presentation, and then in aortic stenosis, and that doesn't mean that these are the only lesions in which there is an elevated risk of ventricular tachycardia and probably far from it, but what it does mean is this is where the data is, and it's a combination of the lesions that are common enough that we have population-level statistics on what happens, but are also well enough tolerated that we're able to get people old enough that we have meaningful data on what happens in ventricular tachycardia. So here's where we're going to focus for most of the presentation. So here's the classic ventricular tachycardia, the one that when we talk about sudden death, we know the most about, and these are intracardiac tracings, and I'm going to walk us through a little bit. I know many people on this lecture will be very sophisticated about reading intracardiac tracings, but what you see here is that, first of all, there's left bundle branch block on the surface ECG. Here's lead V6 that I've circled, and that's positive in lead V6, and you see that that fits the rest of the pattern as well. There's an inferior axis. You see that it's positive in lead II, positive in lead III, positive in lead AVF. So that's a right ventricular VT, and then if you look at the fourth tracing from the bottom, you see that it's labeled as RVOT3, right ventricular outflow tract number three, and you see that the earliest activation is in the right ventricular outflow tract catheter, and in fact, it slightly precedes activation on the surface leads. This is suggestive of a right ventricular outflow tract VT, and this is the classic VT in Tetralogy of Flow, and the one that we have the most data to go on. So the question is, can we do better than what we've known about Tetralogy of Flow for many years, and can we do better than these classic examples that I've told you about so far? The answer is yes, but I want to stop for a second and say that those classic teachings, they're not incidental. The reason I bring them up is because there's a lot of data that has helped us understand what to do with people with both bradycardia and tachycardia that have grown out of those initial observations, and by and large, they still hold true. So why is this important? Let's scroll out for a second and think about this. So most importantly, mortality is on the decline. So if you look at these two graphs, on the left-hand side of the graph are people that have so-called cyanotic heart disease. On the right side of the graph are people who have a cyanotic heart disease, and you can see that between 1980 and 2005, there has been a precipitous decline in mortality for many of these lesions, and in fact, not only in terms of very serious lesions like Tetralogy of Flow and Transmission of the Great Artery, but even for things like ASDs, VSDs, coarctation of the aorta, even PDAs. What that means is that there is an enormously larger population that is surviving from childhood to adulthood, and that means that the substrate for arrhythmia is much more common than it used to be because many, many more people are surviving to become adult congenital heart disease patients. These are data from 2000, and they represent a slightly older era, but notice that all congenital heart disease that survived to adulthood are by definition from an era of surgery and management that is at least 20 years old, otherwise they're not adults yet. And you see that when you look at these older data that was from the 80s and the 90s, that these average ages of deaths are really quite young, a transposition patient at 27, a single ventricle patient at 28, coarctation, aortic coarctation, which is really a relatively conceptually straightforward lesion to get your head around, is relatively young. And that's not to say that everybody dies at age 27. These average age of deaths actually represent a big bell curve where there's a lot of young mortality and then a lot of a little bit older mortality, but you can see that this idea of what are the decades of life in which you care about ventricular tachycardia, this doesn't bear any resemblance to the people that we start to worry about ventricular tachycardia seriously affecting them when they have coronary artery disease or not ischemic cardiomyopathy catch up with them in much older life. So it's important to keep in mind what a young age this starts to affect people. Finally in a different study, this is from 2009, and this is in patients with cyanotic heart lesions. And I've pulled these in patients with cyanotic heart lesions because the data were separated similarly in cyanotic and non-cyanotic, but the data in non-cyanotic heart lesions are very similar. In 1980, approximately 60% of death was from arrhythmia death and 23% was from congestive heart failure. Whereas in 2005, the frequency of arrhythmia death had gone down to 44% and the congestive heart failure had gone up to 36%. And these are the data that are on top of each other that say more people are living, they're living longer, but they're not living disease free. And that's really important to pay attention to and to take into account as we decide what to do. However, what we know is that in the modern era, and modern is describing studies that were published within the last 10 years or so, about 25% of mortality is sudden death. So here's data from Zomer in 2012, here's data from Meyer in 2012, 2010, 2012. And although there are slight differences in what exact percentage of mortality is sudden death, you can see that these four large studies concur that the amount of sudden death is about a quarter. Now, two of these studies drew some of the same data from the Concord data, so they overlap a little bit, but big picture, there are multiple big studies that suggest that about a quarter of mortality in adult congenital heart disease is going to be due to sudden death. The thesis that I'm going to advance for the rest of this talk, the number one most important thing that I'm going to say to you is that sudden death is more than just ventricular tachycardia. And now what I'm going to try to do is put a model in your head that says, the way to think about this is to think about the patient's anatomic substrate. What was the original surgical approach that was done? What subsequent operations were done? Have they had atrial tachycardia? Have they had systolic dysfunction? Have they had diastolic dysfunction? And which of those things contributed to the ventricular tachycardia, which is the common pathway that tends to lend itself to sudden arrhythmic death. But if you don't consider the six things that are on the left-hand side of this slide, considering the ventricular tachycardia and isolation is not helpful in terms of deciding which parts of the puzzle to spend your time and attention in. So the first thing I want to talk about is low ejection fraction. And while there's data on this in the adult population as well, and I'm not missing the fact that we have enormous amounts of data on non-ischemic and ischemic cardiomyopathy with a low ejection fraction, it's not intuitive that that necessarily has to be the strongest predictor in congenital heart disease, but it turns out that it is. So I'm going to show you several studies that show the same thing. And here's a study from 1997 that looked at people who had transposition of the great arteries and they looked at mild, moderate, and severe dysfunction, as well as people who had normal ventricular function. And you can see that the Kaplan-Meier curves for these populations don't diverge significantly until you end up with severe dysfunction. Similarly, for Tetralogy of Fallot, I'm showing you data from a Jack article from 2002, but Tetralogy of Fallot has been looked at this over and over and over again. And in article after article, we find the same data that if you have mild or normal function, your Kaplan-Meier curve doesn't start looking abnormal for almost 25 years out. But if you have moderate or severe dysfunction, starting in your teenage years, your risk of sudden death goes much higher and your cumulative survival is much lower. And then this is an important study from 2012, where they looked at 1200 adults with congenital heart disease, which is a big study in our population. And importantly, they looked at all lesions, where they said Tetralogy of Fallot, transposition, aortic stenosis, single ventricles, AV canal defects, ASDs and BSDs. And what they said was, all right, all we care about is what was your dysfunction and did you have severe dysfunction on whatever your systemic ventricle is? So SFVD in this figure means severe systemic ventricular dysfunction. And this data shows what is kind of a combination of all the data I just showed you, which is If you don't have severe systemic ventricular dysfunction, your actuarial freedom from sudden cardiac arrest is nearly zero. But if you have severe systemic ventricular dysfunction, your 20-year mortality starts to approach 40%. Importantly, atrial arrhythmia is also associated with mortality. So this looked at 38,000 adults with congenital heart disease, of which 5,800 had atrial arrhythmias. And you can see that the hazard ratio for any adverse event in people that had atrial arrhythmias, so the comparison group was the group that had atrial arrhythmias versus the group that didn't. Any adverse event had a hazard ratio of 2.5 with a very narrow confidence interval. And most importantly, mortality is elevated, stroke is elevated, heart failure is elevated, of which mortality and stroke are obviously extremely important endpoints in this population. This is really critical data because it suggests that atrial arrhythmias are associated with mortality. And these are the arrhythmias that you are most likely to see. And for practitioners who don't see a lot of congenital heart disease, the ones that it is easiest to say, I'm going to treat this with medications, but I'm not going to necessarily look into the underlying causes. And if you take a patient with adult congenital heart disease and slap them with some beta blockers or some Sotolol and say, look, I've got control of their atrial arrhythmias, everything's okay. What you're missing is that those atrial arrhythmias were not just palpitations. They were a marker that there is something else in this patient's heart that is telling you that it needs a deeper look. And so this is the early flag. Atrial arrhythmias are an early flag that you need to think very carefully and think very deeply about the patient in front. The reason I mentioned this is this is from a slightly different dataset, but the prevalence of atrial arrhythmias in these populations are very high. So a third of people with Epstein's, almost a third of people with transposition, 25% of people with single ventricles, 20% of people with ASDs, even coarctation, VSDs, there is a really high prevalence of SVT. And since that SVT is associated with an increased risk of mortality, you have to pay a lot of attention to this patient population because you're going to find it a lot. And then finally, pulmonary artery hypertension. So the data that's quoted in this 2018 study in the British Medical Journal is that 5-10% of adults with congenital heart disease will develop pulmonary hypertension. This looked at 310 patients with a mean age of 35 years and 58% had Eisenmenger syndrome and 33% had trisomy 21. So that's probably an overestimate in the United States. There's no way that 60% of the people that we take care of in the United States have Eisenmenger syndrome. Eisenmenger syndrome is a syndrome that results in pulmonary hypertension because of unrestricted blood flow over a very long period of time through a left-to-right shunt, a big VSD that causes so much blood to shunt from the left side of your heart to the right side of your heart that you end up with elevated pulmonary artery pressures and gradually pulmonary hypertension and elevated pulmonary vascular resistance. So this probably doesn't fit our population in the United States, nonetheless, with a median follow-up of 6.1 years, their hazard ratio for death is 3.4 and they did a good job of adjusting for demographic and clinical variables. So what I would say about this study is I don't think their population fits the prevalence in our population, but it's important to recognize that they're finding something real, which is if you end up with pulmonary artery hypertension for any reason, you need to pay a lot of attention to their mortality risk because it's a marker of something bad happening. So let's go back to this because what I've tried to tell you is that there is this whole process and so now let's look at that atrial tachycardia that's in this front and center in the middle column and I told you that if you see atrial tachycardia, if you see systolic dysfunction and we haven't quite gotten to diastolic dysfunction yet, those two things are incredibly important predictors. The thing that's to the left of that is anatomic substrate, original surgical approach and subsequent operations. Your job when you see these markers of concern for mortality is not just to treat atrial tachycardia and not just to put them on guideline directed medical therapy for systolic dysfunction, but to look to the left of this diagram and say, okay, what is this anatomic substrate? What was the original surgical approach? What were the subsequent operations? And as Nishant said during the introduction, sometimes you need to get help. Sometimes you get a pediatric cardiologist who can help you understand exactly what's been done. The same way that I often turn to my adult colleagues and say, hey, let's talk about atrial fibrillation, which is something you're far more of expert in than I am. So how do you find this VT? Well, Holter is inefficient. This is an analysis from Richosic in 2013 and they looked at 225 patients over 10 years and these were serious diseases. Atrial switch for transposition of the great arteries, single ventricle physiology, which is repaired by something called the Fontan operation. And then Tetralogy of Fallot, which is this disease I keep telling you about that we study a lot. And 80% of those were ordered for screening. That's good because it means that that's the most likely reason that we order Holter's. That's consistent with our clinical practice. And they found nine sustained VT and 8% of all for Holter's. It made no difference on analysis whether you had non-sustained VT. There's no difference in subsequent rate of sudden cardiac events. There were only seven subsequent events. So it may be that this is just not adequately powered to tell the difference. But as you see in many studies of adult congenital heart disease, there are very few registries that have large numbers. And many of the data we have is based on three digit or four digit numbers. So these are the most recent best data we have on whether or not you can screen for Holter. And the answer is routine screening without anything else is not an efficient way of detecting ventricular tachycardia. Diastolic dysfunction is associated with VT. So this is that diastolic dysfunction that I told you about, you know, in that diagram I've shown you a couple of times. This is data from 2013 where they looked at 556 patients with atrial geoflow. This is a multi-center retrospective cross-sectional study with echo evaluation. And as you can see, the sustained VT frequency between left ventricular diastolic dysfunction and no left ventricular diastolic dysfunction was different. That was about 10% versus about 30%. First of all, it's important to note that in all comers, there was a similar frequency of VT to the non-sustained VT that they saw. But this is sustained VT. So this is a particularly sick group. The group that is having 30% of sustained VT is a particularly sick group. But even the comparison group that's having 10% sustained VT is a sick group. But even in this slightly sicker group, what you see is that when you run the positive predictive and negative predictive values on the statistics that they provided in the paper, which I will tell you I did, they didn't provide this, so this is my secondary analysis. If you look at the positive predictive value, you'll see that 29% of them ended up with VT. So even in this very sick group, a diastolic dysfunction did not mean it was inevitable that you were going to end up with VT. The negative predictive value suggests that normal diastole is in fact safer. The reason I bring this up is because as we start to put the pieces together, we're going to talk about our worry for diastolic dysfunction. And the important thing is to say that while diastolic dysfunction is heavily related to outcomes, that's part of why I showed you that slide about heart failure early on. It's not necessarily related to VT and sudden death in a way that you can predict on an individual patient level. What do you do about it? Well, you can try ablation, but don't count on it. This study from 2004, which is early in the experience, is one of the most honest studies I have ever read. It was a particularly clear procedural result from a single center. And they did 20 procedures. They felt like they had acute success in 50% on the basis of intention to treat analysis. And they point out that many of the ones they just thought had unstable VT and they couldn't do pace mapping. They had anatomic or access sites problems, which is extremely common in congenital heart disease, where they just couldn't get something going. But even their acute success ranges are only 83%. And the recurrence at about three and a half years, so follow up is 40%. So that's not a great outcome from ablation. It's certainly not nothing, but it's an outcome that suggests that you can't use it as a final endpoint. This is data from Yang in 2019, so that was just published this year. And this is data from Colorado, as well as a couple of other centers, including CHOP, that have a great deal of good experience with ablation. So I would expect these to be highly reliable data. They have only 48 procedures. You can see that VT in congenital heart disease is not a common ablation procedure. And you can see that if you look at their acute success in patients, they had about 75% acute success and their recurrence at first follow up is about 20%. Now these are slightly different. I've called these data from a paper that didn't report it exactly the same way. And in fact, there are a number of things that may have improved their outcomes. So their acute success looks like it's lower than the previous article, but their intention to treat analysis would look better. Probably some of that is because pace mapping and 3D mapping have gotten better. Probably some of their less recurrence is because we now have irrigated catheters. But nonetheless, these are still not perfect results. And you can see that they've not changed categorically over the course of the last 15 years, despite the fact that there's been enormous amount of change in our technology that we use for ablation. And part of the reason for this is because doing ablation in congenital heart disease in the ventricle is quite complicated. So by far, tetralogy of flow is the easiest lesion to understand ablation because the surgical approach is reasonably straightforward. We have done a lot of them, so there's a lot of opportunity to understand, and the anatomy is almost always the same. And so I'm not going to walk us through every one of these, but I'm going to illustrate it as an idea. Here hopefully you can see the screen with the pointer. Here's an anterior look at a heart that is obviously postmortem. This is the right ventricle. The left ventricle is over here to the patient's left. You can see that a pre-existing right ventricular outflow tract patch has been put over the right ventricle, which leads to the pulmonary valve and then out to the pulmonary arteries. There are two anatomic isthmuses that can support reentrant tachycardia. One exists here lateral to the right ventricular outflow tract and before the tricuspid annulus. One of them sits between the right ventricular outflow tract and the pulmonary valve. So one isthmus here, one isthmus here. Here again is a similar look at someone who has this tricuspid annulus, and you can see here that this number one isthmus is still intact, but here this transannular patch has gone through the pulmonary valve, so that second isthmus does not exist. And then opening up the heart to look at isthmuses three and four, here's the reflected VSD patch. It belongs over this perimembranous VSD, and you can see that here is the outlet septum over here, and here's the pulmonary valve, and here's the interior third isthmus. And then again, looking at an opened heart, where here you're looking up at the tricuspid valve annulus, and here's the muscular VSD that if you're looking through it will eventually lead you to the left ventricular outflow tract. This is the fourth isthmus here. These four isthmuses can support any type of circular tachycardia, either going amongst each other, or doing figures of eight between them, or going around in multiple different directions. And you can imagine that trying to ablate these four areas, you need to have an incredibly sophisticated mental model of where you're trying to ablate, because what you're trying to do is ablate between patches and annuluses, between isthmuses that may or may not exist. And often, through periods where you're doing it adjacent to the VSD patch and relatively close to the conduction system. And so it's really important to have a model of what the patient has done and what the patient has had done to them surgically before you go in and start trying to cause lesions that may or may not ablate. This is Tetralogy of Flow, but of course, each lesion has its own anatomic differences, has its own patch methods, has its own method of repair. And so the first thing to do when you start to make a plan to do ventricular tachycardia ablation in a patient with congenital heart disease is to sit down with the operative notes, sit down with somebody who understands the anatomy very well, sit down with three-dimensional cross-sectional imaging, and make sure you understand where the VSD is. Make sure you understand where the patch is. Make sure you understand where the artificial valve is. So you know what to target when you get in there and time is of the essence. What about ICDs? The data for ICDs in children and young adults is quite different than the data in adults. The rate of successful defibrillation in children, meaning a defibrillation for an event that seems likely to have been a aborted sudden cardiac death event. Now, I'm going to put aside what successful ablation really means and whether every one of those is a sudden death, but a successful ablation, sorry, a successful ICD shock is about a third, but it's important to recognize that the lifetime risk of inappropriate shocks is about 46% and unsuccessful ablation at 21%. Now, this is a pie chart, so you see that it sums to 100%, but you can imagine there are people who get both inappropriate and successful shocks, or inappropriate and appropriate shocks, and you can see that what that means is the way this works is that you get categorized into the most severe forms. So people who got an unsuccessful shock got put into unsuccessful, people who were in successful had a successful or an inappropriate, and if all you had was inappropriate, it was 46%. So these are people who got shocks and where they ended up. These data have been remarkably consistent over time. These are particularly pulled from Christina Miyake's work in 2013, but Sylvia Priori's work and a whole bunch of articles leading up to it have all said that about a third of people who get shocked will have successful shocks and that inappropriate shocks are very common. The overall complication rate for young people with ICDs, it's about 25 to 33%. That's not in the first five years, but the lifetime complication rate is about 25 to 33%. So this idea of taking young people, and when I say young people, I mean people under the age of 40, and giving them ICDs, you have to be really, really prepared for the fact that it is a complicated process and that it can lead to a lot of difficulties. Devices and leads break sooner. So the data from the Medtronic Connect document is that in adults, and this is where the data are really most robust, the age at first implant, an average age at first implant is 74 years old, generators last 11.3 years, and the number of leads still in service at 69 months are 99.8%. That's data from a publicly issued Medtronic document. That doesn't mean it's the only thing, but it's the most recent data that I have access to. But nonetheless, the data in a whole bunch of papers is that the number of leads at service at 10 years is north of 90% by a good margin, and close to 95 or 99% depending on who you look at. Kids, it's very different. The age at first implant is average of 5.7 years of age. Generator duration lasts on average 5.8 years. So when we tell kids that their generators are likely to last only five to seven years, that's not just because we're looking at retrospective data of generators that are from a generation ago, it's because we've always known that generator duration in kids is shorter than it is in adults. Leads still in service at 69 months, less than 90%. And that's important because it's an entirely different mindset than having leads that are almost always gonna still be in service a couple years later. And 50% have fractured by 12 years. In most adults, there isn't a big worry about what's gonna happen in 12 years. If your age at first implant is 74, and that means that 12 years out is 85, there's going to be a substantial percentage of people who have other comorbidities that are gonna raise their heads between age 74 and 86. I think I said 80, whatever, but 86. In that 12 year period, a lot of other comorbidities are gonna come up. But in children, the chances that 12 years later, their major comorbidity will still be their cardiac disease is much, much higher. And so the idea that the time to 50% fracture is 12 years means that if you have somebody whose average age at first implant is five and a half years, 50% have fractured by the time they're 17 years old, and then the clock is starting again. That means it's exceptionally important to think about primary prevention ICDs in young people. And if you get a 21 year old into your practice that you're thinking about doing it, it's really important to think carefully about the recommendations for primary prevention ICDs in adults with congenital heart disease. What I wanna caution people against is the phenomenon of saying, all right, I'm gonna apply the adult data, and then I'm gonna apply a little more leniency about putting in ICDs a little earlier because I'm worried about this because I don't see it very much. Instead, I would really encourage you to think deeply about it and think about the data I just gave you about frequency of shocks, the frequency of lead fractures, the frequency of complications, and say, if you need someone to help you decide about primary prevention ICDs, by all means, engage someone who's deeply invested in congenital heart disease. This is from Paul Carey's 2019 work. It draws on a bunch of different recommendations, including the main recommendations from HRS-ACC, the lead author of Who Is Epstein? But this is a nice, tight summary. And it says there's only one class one indication for primary prevention ICDs in adults with congenital heart disease, which is adults with congenital heart disease, systemic LV ejection fraction less than 35%, biventricular physiology, and New York Heart Association class two or three symptoms. That's a lot of boxes you have to check in order to have a class one indication providing prevention ICDs in congenital heart disease. 2A is restricted to tetralogy of flow because that's the only place we have good data. I told you at the beginning of this talk, I was going to talk a lot about tetralogy of flow. And unfortunately, that's because that's where most of our data resides. So multiple risk factors, systolic or diastolic dysfunction, non-sustained VT, QRS duration over 180 milliseconds, extensive RV scarring, inducible sustained VT at EP study. Turns out that the best data for doing EP studies to induce sustained VT is in tetralogy of flow. It does look like there's some positive predictive value to doing them in tetralogy of flow. Unfortunately, there has not been universally good data that suggests that every congenital heart disease lesion is associated with a high positive predictive value. And so tetralogy of flow is the only place that that data still is. Class 2B, now we're getting into places we're really quite unsure, singular systemic right ventricular ejection fraction that's low, especially if there are additional risk factors. And I'll let you read those either now or on the posted website at some point. And then finally, ICD therapy at adults with congenital heart disease with syncope of unknown origin and hemodynamically significant sustained VT at EP study. And the reason that that's 2B is because there isn't a lot of data supporting that that's definitely true, but the preliminary data that is in tetralogy of flow may or may not be applicable. And there's some smaller and anecdotal data that it may make sense, which is why it's 2B. That's not a lot to go on. If you look at the adult indications to put in primary prevention ICDs, there are enormous studies with 40,000, 50,000, 100,000 patients that are all giving extraordinarily nuanced indications for primary prevention ICDs. That's not where the field of adult congenital heart disease is at. And what that means is that these conversations with young adults who are about to be considered for ICDs need to be highly tailored and they have extremely long-term implications. So here is a patient who is 23 years old at the time of this chest X-ray, PA and lateral. And you can see that this has gotten very complicated. This started as someone who had a pacing indication, and you can see that she has a pacing lead in the ventricle and that that has stretched to the point where it broke and eventually was taken out. A second one actually had the same thing. These are not what leads look like when they go in. They were put in when she was much younger. And then you see that she has subcutaneous patches in place. She has subcutaneous coils that have been run, in this case, all the way along her back, all the way up her back and all the way near where her scapula is. Here's that coil in the other projection. This is a second coil here that runs this way. You can also see here that she has multiple pacing leads on her heart. These are epicardial pacing leads. And an epicardial box down in here, as well as these abandoned leads here. So what you can see is that the process of going through life with these pacing systems can get quite, quite complicated. And she's 23 years old, which means that at each step of the way, you have to not only say, what am I doing as I put in this ICD this first time, but what am I gonna do if it breaks once? What am I gonna do if it breaks twice? What am I gonna do if it breaks three times? And how do I be really sure that I'm doing the best thing for this patient over the long run? What about transplant? I'm not gonna say very much about transplant. Transplant in the setting of other risk factors, there are similar post-transplant outcomes to other non-congenital heart disease patients. So congenital heart disease in and of itself is not a reason to not put someone on the transplant list. This is from a circulation paper from 2008 that suggests that the risks in cardiac transplant among these patients are similar. I think very few electrophysiologists want to get into a position where they're looking at ventricular tachycardia and addressing it with transplant. And I wouldn't advocate for that. But as you eventually get a very, very challenging case and your hands are tied and you can't figure out what else to do, you should at least know that this should not be a contraindication and that referring to somebody who is expert at transplant and congenital heart disease is a good idea in congenital heart disease patients. So let me summarize for a second here. So this is back to that same screen, but this time I'm gonna try to tell you a little bit about the data that I just summarized. So are we fixing the problem? Well, our original surgical approach is getting much, much better. I showed you that in the very second or third slide where I told you that mortality from 1980 to 2005 is declining precipitously. And most of that decline is because our surgical approaches have gotten better, our bypass times have gotten better, our post-surgical care in the cardiac ICUs has gotten better and our approaches to identifying the patient have gotten better. So the original surgical approach is much, much better. The problem is that that is now creating a larger surviving substrate that will go on to have atrial and ventricular arrhythmias that will become the issue for electrophysiologists. We are getting better at subsequent operations. In some case, we're eliminating the need to have as many subsequent operations. But as those operations have gotten more complicated and people have lived longer, we end up in a situation where we need to take more operations into account. And every one of those increases the burden of potential scar that may eventually lead to anatomic substrate that becomes tachycardia. We know now that atrial tachycardia is an important risk factor for sudden death and for morbidity and mortality in men and for mortality in general in adult congenital heart disease. We also know that it's a substantial source of patient dissatisfaction. And when you see atrial tachycardia, it's not just dealing with atrial tachycardia and making it go away, but considering all those other anatomic and surgical problems that are listed to the left to ensure that you're not putting them inevitably along this right-hand red arrow that leads to ventricular tachycardia and mortality. Ventricular tachycardia is in fact a marker of mortality. And the idea that you're looking for both atrial and ventricular tachycardia is important. And by far, systolic dysfunction is the most important indicator for mortality. But the problem is we don't have good therapies to fix systolic dysfunction. And I will let you all think about our successes in heart failure regimens, our successes in putting in VADs, our successes of transplant, and those are definitely valuable characteristics in our armamentarium. But in terms of getting a 10-year-old to age 90, very few of those are going to reverse very severe systolic dysfunction in a sustainable way for 80 additional years. The diastolic dysfunction is almost surely important. We don't understand it very well yet. And not only are these lesions contributory to diastolic dysfunction, but almost for sure, the operations that we're doing, the bypass that we're doing, the surgical intervention that we're doing contribute to the underlying problems of diastolic dysfunction that are exacerbated by their original anatomic substrate. So what you see here, and the point I'm trying to make is that we as a field are making enormous amounts of strides in decreasing mortality, and that's been reflected in what happens. But some of the things that you need to consider over the next 10 to 20 years as you see these patients haven't been solved even by the very best heads in the field yet. And so staying current and trying to understand what we can do to ameliorate these things as we move forward is probably an important part of this puzzle. So I'm gonna spend three or four slides here talking about a similar patient. And this isn't a real patient. This is a triage mental model. And then I'm gonna ask some questions that I think hopefully are part of Nishant Verma's tremendous process here. So let's imagine in our head a 19 year old with Epstein anomaly. Epstein anomaly of the tricuspid valve is an anomaly where the tricuspid valve becomes plastered to the septal wall during development, and the right ventricle becomes very small, the right atrium becomes very large, and there's often an association with Wolff-Parkinson-White syndrome. This person has had a repair to try to reconstruct a tricuspid valve, and they pass out while standing in the sun watching a soccer game. And comes into the emergency room, and the heart rate is 79. The blood pressure is 109 over 65. They're fully saturated. Their respiratory rate is 19. They have right bundle branch block and a slightly wide QRS duration. They have no prior ablation history. The EKG looks the same. There's a systolic murmur that sounds like a tricuspid valve murmur, and is otherwise well. So those are about as reassuring as vital signs and reassuring of an initial screen as you could see in an emergency room for someone who just had syncope with this disease. So what other information do you need to make a good decision? How do you know that this patient is not having cardiac syncope? And in a different lecture environment, I would let people weigh in, but what I'm gonna tell you is that's that left side of the column of the diagram that I keep showing. What exactly was their anatomy? What exact tricuspid valve repair was done? How old were they when they did it? What happened to the tricuspid valve afterwards? What's gone on with the rest of their anatomy over time? And what else is happening in terms of their arrhythmia substrate? What if the heart rate's 125? What if everything else is almost exactly the same, but the heart rate is 125? Right bundle branch block pattern, same QRS duration, otherwise well. I think most people who practice with congenital heart disease would tell you that an adult, and a 19 year old in this case is an adult, who has serious congenital heart disease, who comes in with a heart rate over 100 is in some kind of atrial arrhythmia until proven otherwise. And that's what I would encourage people to think about. Now, it could be that they're in an atrial arrhythmia at a heart rate of 50, or at 70, or 195. And I wouldn't ask you not to apply your clinical judgment. But no matter how good the rest of the vital signs look, an adult congenital heart disease patient whose heart rate is above 100, assume that patient is in an atrial arrhythmia or a ventricular arrhythmia. But importantly, assume that they're in arrhythmia until you have definitively proved otherwise. Sending someone out of the emergency room, no matter how good they look, because of mild dehydration or something else with a heart rate like this in an adult congenital heart disease patient, you are missing that atrial tachycardia that we just established is highly associated with morbidity. And you may be the last person who has an opportunity to really identify that because they may go home, their tachycardia may break, and they may go on with regular follow-up without someone recognizing that that sentinel event has occurred. All right, now let's change and say the heart rate's totally fine. Heart rate's 79 now. Everything else is exactly the same, but the EKG shows a QRS duration of 92 milliseconds without right bundle branch block. And a year ago, the ECG showed right bundle branch block with a QRS of 115. In this setting, my advice would be assume this person is pre-excited unless you have data otherwise. Epstein's anomaly patients who've had tricuspid valve repairs, almost all of those have right bundle branch block pattern. So the intermittent pattern where your heart rate is low and sometimes you have right bundle and sometimes you have a narrow QRS is likely pseudofusion in the setting of ventricular pre-excitation as opposed to someone becoming more normal when they've had a syncopal event. And Epstein anomaly patients who have ventricular pre-excitation, they need ablations. And so sometimes it turns out that the PR is short and there's a classic delta wave and it looks like you could pull it out of the textbook, but the absence of right bundle branch block in someone who should have it on the basis of their anatomic disease is almost always an invitation for you to look closer. Do you have to memorize that about Epstein's anomaly? Sure. Is this a lecture enough for you to know in the back of your head every single anonymously and what their EKG should look like? No, this isn't a sufficient lecture for that. But what I would tell you is that idea of looking back at the last ECG and saying, has the QRS changed and does this mean something to me? That's an important step. That's that left column of that diagram. I keep showing you where you say, what is their lesion? What is the surgery they had to repair and what are the consequences of that surgery? Finally, that same 19 year old with a heart rate of 145, but now the blood pressure is low. The saturation is low, poorly perfused, pale. QRS duration is 150, left bundle branch block. This person is having a VT event until proven otherwise. And this is something that I assume that everybody on this call or everybody on this Zoom meeting would look at and say, okay, I've got this. Heart rate of 145, different QRS, left bundle branch block, who's poorly perfused. I'm in the ACLS world. Let me go down that. And that's the last point I would make is don't get too confused. If you have someone who is perfusing poorly, who has an abnormal QRS duration and has left bundle branch block and you can't demonstrate that they're in a matrial rhythm, think very carefully about whether or not they're in ventricular tachycardia and walk yourself down your ACLS protocol. So in summary, sudden death is the cause in about 25% of adults with congenital heart disease. That means it's an important number and they aren't dying at 95. They're dying younger and we want to prevent it. We as electrophysiologists would like to continue this trend of sudden death becoming sudden death plus heart failure, not because I want anyone to have heart failure, but because heart failure is a marker that we're preventing sudden death. And that's, as an electrophysiologist, the next first best step for us. We need to move over time from this model of VT and Tetralogy of Flow, which has taught us such an enormous amount to the systematic evaluation that I kept talking about, that red arrow slide that I showed over and over, where you say to yourself, what's going on with atrial tachycardia? What's going on with ventricular tachycardia? Is there systolic dysfunction? Is there diastolic dysfunction? How do I demonstrate those things? And then to assure you that you're not alone, there is no single best fit therapy. Drugs, ablation, ICD, transplant, all of these things are options. But most importantly, as soon as you find that an adult congenital heart disease patient has arrhythmia substrate, go looking for the underlying causes and go get help if you need to, because you are, by intervening early and making sure you understand all the things in the systematic evaluation, you are impacting their long-term outcome. That data about the early identification of atrial tachycardia impacting mortality, the data about systolic dysfunction impacting mortality, this is your opportunity to intervene. And if you need help trying to understand the best way to piece out the underlying causes, we're here for you. All right. So I'm going to pivot here to the questions. I see that there are nine people that are currently on the call. So I'll wait until we get some meaningful fraction voting. Greg, maybe I can ask a couple of questions. Yeah, please. Well, you know, as these patients acquire more adult medical problems, specifically, I guess, coronary disease, but also high blood pressure, diabetes, et cetera, does that put them in a higher risk category as time goes on? Almost for sure. It's hard to imagine that it doesn't. There are some lesions in which we see accelerated coronary vascular disease, and that's probably been the area that we have the most experience. Unfortunately, it's only been relatively recently that a large enough number have lived and survived long enough in settings that we can meaningfully start to look at those outcomes. There are some studies. I showed you the Bucciardi study early. There are a number of people, Paul Carey's group has looked at that. I don't want to not mention many of the good work that's been done on this, but the answer is we are only starting to collect that data. Okay, I'm going to end the poll. So I'm going to talk about this briefly and say that the 67% are right in that that has not been shown to increase sudden death risk. The two who answered pulmonary hypertension, there is data that people with pulmonary hypertension have an elevated hazard ratio for sudden death risk in an adult congenital heart disease, but you're right that that pulmonary hypertension is not a ubiquitous feature of adult congenital heart disease, but among those who develop it, there is an elevated risk of death. Atrial arrhythmias and systolic ventricular function do increase mortality risk, and although not all of that is sudden death risk, it is both mortality and heart failure risk in several studies and sudden death in some studies. So I don't know if, which of the fighting lesions have the highest risk of arrhythmia? And then the lifetime mortality risk. So which of these has the highest lifetime risk of any arrhythmia? Greg, there's a question here about instead of routine Holter monitoring, have people studied loop recorders as a method of risk prediction? Yeah, the number of people who have started to put loop recorders in folks with congenital heart disease is starting to grow, and there are some preliminary data on the results of implantable loop recorders in congenital heart disease. Probably the earliest of those was a first author named Patty Frangini in the Boston Group. Several other authors have looked at that since then. The answer is it's a mixed bag, especially since the duration is only about three years of studying. I would hold them off still for people who have high risk characteristics, as opposed to people who are looking for routine screening for arrhythmia disease. So which of the following lesions have the highest risk of arrhythmia at any time? You have definitely identified the two lesions that we spent most of the time talking about, and the division is probably the one that most people would say. Epstein anomaly probably has the highest risk of all arrhythmia substrate, atrial AV reentrant, and ventricular arrhythmias. The point about tetralogy of flow that I would make again, and have made a couple of times, is that's where we have the most data. But it's important to recognize that even though most of our data is in tetralogy of flow, it does not mean that it's the most severe lesion of the lesions we deal with. And Epstein anomaly of the tricuspid valve, especially severe Epstein's, that ends up with a major repair or a single ventricle physiology, is a particularly high risk lesion. There are others as well, but the reason to have this question is to make the point that despite the fact that tetralogy of flow comes up over and over and over, it doesn't necessarily make it the most high risk lesion that we have. And now, that being said, looping back to tetralogy of flow, since this is the only 2A indication that we have for primary prevention in adult congenital heart disease, I thought I would mention, are any of these not a published risk factor? Oh, I'm sorry, I didn't wait long enough for all of them. So this is part of the problem. And the reason I put this third one in here is to say the data are conflicting. Atrial tachycardia is clearly associated with a higher morbidity risk in all patients, and including in studies that are overrepresented in tetralogy of flow. That being said, the risk factors that were published for primary prevention ICDs in tetralogy of flow did not include atrial tachycardia. And what I would tell you about this is not that atrial tachycardia doesn't matter, but that it's important to be careful about putting in primary prevention ICDs. And that what I would encourage people to do is when you're faced with the question of whether or not to put in a primary prevention ICD, to think as carefully as you can about the data that's published and the recommendations that are published, and not to take the gut instinct, I have somebody with congenital heart disease who also is having an arrhythmia, and therefore I should give them an ICD to prolapse against sudden death. Think as carefully as you can about their clinical situation, and remember that there are a bunch of downsides that happen as well with ICDs. So I thank everybody for participating in this. I'd like to thank Nishant especially. He has been a tremendous colleague of mine. He has been inspiring to me in terms of the amount of time he spends teaching, and he does all of that while also being an accomplished ablationist, and has been a partner in trying to get channelopathy patients seen. Brad Knight has been a leader in this field and a mentor of mine, and I feel lucky to get to work with him. But all of our colleagues at Northwestern Medicine have taught me an enormous amount, and we are lucky to be connected with such a talented group of electrophysiologists. So Susan Kim, Rishi Arora, Alex Chikos, Al Linn, Rod Passman, Omid Zarqoui, and Stuby Patil. It's a tremendous group to work with. It's a tremendous group to learn from, and we are lucky and fortunate that between Lurie Children's and Northwestern Medicine, we have such a strong collaboration and a strong ability to take people from infancy all the way up through adulthood. And with that, I'll take any questions that have come through the chat room, or answer anything else that I can along the way.
Video Summary
The transcript discussed the risk of sudden death in patients with congenital heart disease and the importance of identifying underlying causes and risk factors for arrhythmias. The speaker highlighted the need for a systematic evaluation of patients, including consideration of atrial tachycardia, ventricular tachycardia, systolic and diastolic dysfunction, and the impact of surgical interventions. The transcript emphasized the importance of early intervention and collaboration with specialists in the field. The use of Holter monitors and loop recorders were mentioned as potential tools for detecting arrhythmias. The discussion also touched on the role of ICDs, ablation, and transplant as treatment options. The transcript concluded by emphasizing the need for ongoing research and the collaboration between pediatric and adult congenital cardiology.
Keywords
sudden death
congenital heart disease
arrhythmias
surgical interventions
early intervention
Holter monitors
ICDs
ablation
transplant
ongoing research
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