Chapters Transcript Video Electrophysiology for the Primary Care Providers Great. Well, thank you for um inviting me to give today's talk. I'm excited to kind of want interface a little bit more with some of the primary care physicians obviously in our um children's hospital community since I'm fairly new to U CS F. So the the topic is a little bit of a potpourri. Um It's very vague in the title and that's Electrophysiology for the primary care provider. And the reason why it kind of highlights these topics is I felt that they were the highest yield and the things that you're gonna see the most common in terms of your practice and how you interface with the electrophysiology department and the types of issues that you're gonna see. Uh two caveats. The first one being that we are talking about Children with structurally normal hearts today. So we are not including the whole gamut of patients with congenital heart disease. So just take those off the table or add a little bit of asterisk with everything I say. The second um component is as much as I try to give generalizations and sort of hard and fast rules. Obviously, that's always impossible in cardiology. So if there's ever a situation where you have a question. Um, one of the other things I wanted to do is to make sure that you saw me and met me and that have the agency to reach out and contact me via email or other means if you have specific questions that you're curious about. All right. So to start off, I have no financial disclosures but fingers crossed maybe one day. Um, today's topic, like I said, uh is a little bit of a smattering of different things that I felt were biggest yield. The majority of the talk will be spent speaking mostly about super ventricular tachycardia, SVT. And again, because you are really the touch point, you are usually the first interaction that a family is gonna have before they get referred to cardiology and specifically electrophysiology, we'll talk about the two most common mechanisms. Hopefully, it gives you some better language and examples and ana in which to explain them and not only explain them to families, but for you to have a better understanding yourself, we'll speak briefly about the clinical presentation, obviously, the role of the primary care physician in all of this, including management. And then I thought it would be fun to talk a little bit about kind of the common fa Q and myths that are out there about SVT. These are things that I get asked uh at least weekly, if not daily. And some of them I even got asked earlier today, which is, uh, not plug. I promise we'll speak briefly about Bradycardia and kind of PAC S and PV CS because I think those are common things that you're getting see are being seen in your primary care clinics. Uh We'll take a moment to do kind of a fun activity where we look at ECG findings. Um, we'll have a handful of things that I think are really like, can't miss always abnormal, always require referral. They're good, kind of hard and fast rules and then a few that are typically almost always normal variants that you can kind of um watch over time or at least reach out via email that don't require an urgent referral. And then the last component of what we'll talk about is really my second hat, which is cardiovascular genetics and inherited arrhythmias. So my phd is in genetics and it's really kind of the other non interventional component of what I do. We'll speak briefly about what the inherited arrhythmia clinic does and kind of who and why they should be referred. And we'll summarize everything at the end. What I think are some good take home points. So svt a word about nomenclature and definitions. So obviously, this picture is not a surprise to anybody in the audience. Um The conduction system has three primary parts, the sinus node, the A V node, and the hyper system sinus node functions as your pacemaker, your A V node, the way that I like to describe it. It's sort of like a gatekeeper works like a bouncer in the middle of the heart. And that's because you can see that the top chambers, the atria and the ventricle, they're separated by valvular tissue, which is fibrous. It's non conducting tissue, essentially functions like electrical insulation, which means the only way for electrical activity to get to the bottom chambers is through the A V node in a quote normal heart. And that becomes important when we talk about different types of SVT and how certain reentrant mechanisms occur. And then the hyper Kinji system, the reason I highlight this is because the hyper Kinji system is really what drives efficiency in an electrical and mechanical heartbeat. It is why our QR S is narrow at baseline. And if you understand that concept, then it becomes more apparent why certain tachycardias are wider versus narrow. So by definition, SVT is any tachycardia that originates above the hiss bundle, which includes all of these tachycardias, right? So by true definition, SVT is an umbrella or blanket term. Now, obviously in like layman's and day to day conversation, we're really talking about two types. But technically SVT is sinus tachycardia, atrial fibrillation, atrial flutter jet, those are all forms of SVT. But really and again, kind of the day to day conversations we have with families and each other, we're talking about these two kinds, a V reciprocate, reciprocating tachycardia or a VRT and A V nodal reentrant, tachycardia, A VN RT. So moving forward when I refer to SVT, these are really the two I'm talking about and these are the two we're gonna focus on to give you a general understanding of the mechanisms, how they're different but why at the end of the day, we really don't care. So these are the two general mechanisms of quote classic SVT. On the left hand side, we have accessory path way mediated tachycardia, which is a V reciprocating tachycardia. This essentially implies that there is an accessory pathway that bypasses that electrical insulation of the valves. This is includes WPW and any type of accessory pathway on the right. This is a V nodal reentrant tachycardia and essentially what it is, it's a circuit inside the A V node. Now, both of these imply that there's a circuit of electricity that self perpetuates and that explains the symptoms that patients feel sudden onset tachycardia, sudden onset tachycardia, a fixed rate, narrow complex SVT. So let's talk about accessory pathway mediated tachycardia first. So this is classic A VRT. Now, the nomenclature here can start to get really confusing very quickly. There's a lot of different acronyms and they sort of sub categorize in different ways. But if you really just think about the two types, one of them is an accessory pathway and the other is reentry inside the A V node, you'll be able to explain them much more simply to your patients. So this is due to an atrial ventricular accessory pathway. So literally a connection between the atrium and the ventricle. And the reason that we actually specify that is there are lots of different types of accessory pathways. Technically, you could have an accessory pathway that connects any two structures, the atrium to the A V node, the atrium to the hiss bundle, the hiss bundle to the ventricle. Those are all forms of accessory pathways, but they're rare and uncommon. This is the classic one, atrioventricular accessory pathways. This is the most common cause of tachycardia in a neonate. So you have a newborn or you have a 10 year old who had SVT as a baby. This is almost always the mechanism of tachycardia. So it's way more common in the infantile neonatal period. And then as you transition to getting older, the ratio starts to switch to the other kind. Now, the directionality of the accessory pathway determines the type of SVT. Now this starts to again add in a whole another set of acronyms which can get really confusing. But think about it this way, your typical quote normal conduction goes down your A V node, orthodromic SVT carries along that same pathway Ortho meaning straight or normal. So you're going down the A V node in the hyper Kinji system and going back up the accessory pathway. So the conduction up the pathway is from the ventricle to the atrium. This is the most common form of VT. And because we're using the hyper Kinji system, again, that superhighway that conducts our electricity very efficiently, we're always for, you know, generalization purposes going to have a narrow complex tachycardia, that's what generates a narrow complex tachycardia. So then what is WPW, how does like all of these again, three letter acronyms tie into this? So Wolf Parkinson wider WPW purely refers to part of the directionality of the accessory pathway, meaning that it has the ability to conduct antegrade or from the atrium to the ventricle, which if you'll notice is the opposite direction of the actual SVT I just described. So let's talk a little bit more about WPW and how it's a subset of accessory pathway um sort of types. So it refers to pre excitation of the ventricle from antegrade conduction. So on the right here, again, these are pictures you've all seen before. You have the sinus node that fires off and sends electrical activity to the two top chambers. Now, without the presence of an accessory pathway, all of the electrical activity is forced through the A V node. And again, think your AVI node is a bouncer. It's a gatekeeper does quality control. As you traverse the A V node, there's a little physical pause. And we see that on the EKG as a normal pr interval, a flat isoelectric period, that's because the A V node is doing its job, an accessory pathway on the other hand does not have the properties of an A V node. It does not produce that pause. You just immediately go down to the ventricle and you start exciting the ventricle before the A V node. And then the degree of preexcitation mostly just depends on the percentage of A V node conduction versus the percentage of an accessory pathway. And really, it's just like real estate. It's all about location. The closer you are to the sinus node, the more accessory pathway activation you get the farther away you are, let's say you have a pathway on the left lateral A B groove, you're gonna hit the A V node way sooner than you are your accessory pathway. And the preexcitation is gonna be pretty subtle. So it really just comes down to how much preexcitation you have is location, location, location. So WPW importantly is not a form of SVT. It is literally a finding on the EKG. So you can have WPW and never have SVT that seems very counterintuitive because the SVT typically is going down the A V node and up the pathway and you just might not have a pathway that can support that. So there are definitely patients who can have one without the other. Another way to think of it is that all WPW is caused by an accessory pathway but not all accessory pathways cause WPW, meaning we don't see the EKG findings of a short PR and a delta wave and the reason we care because you're like, well, why does it even matter? Like, why don't we just call them all accessory pathways? The reason we care is that WPW has an associated sudden cardiac death risk and on average, that comes out to about 0.25% per year. So why is that? Because the WPW sudden cardiac death risk is actually independent of the SVT. Why is that? So on the left hand side here, this is an example of atrial fibrillation. So as we age, our atriums develop just chronic fibrosis, that's a typical part of aging and that fibrosis can predispose to atrial fibrillation. And in fact, I'm sure most if not all of you either have a family member or know someone with atrial fibrillation, it's like over half the population above 70 has a fib super super super common in typical atrial fibrillation. Your atrium is going not exaggerating about 500 to 700 beats per minute. Now, obviously, that could not be conducted down to your ventricle. It would not be a perfusing rhythm and you die, but that's where your A V node comes in, right? It's a gatekeeper, it's a bouncer. It is protecting your bottom chambers from the atrial fibrillatory effects of the arrhythmia. So instead of letting every beat go through it, lets I don't know one out of 2030 5010, whatever it is. So what you end up seeing on the EKG is atrial fibrillation with variable conduction through the A node, it's protecting your bottom chambers. That's what it's supposed to do. On contrary, accessory pathways do not have those properties, right? An accessory pathway does not decrement and does not limit the amount of electrical activity, it just goes to its max and then it stops. The problem is we don't know what every individual accessory pathways max heart rate is. So, so in this scenario, on the right hand side, you have atrial fibrillation and some of that goes down the A V node, but some of it is also going down the accessory pathway and this is what we call pre excited. The pre excited is again just the sort of formal version of WPW atrial fibrillation. But the problem is you can then turn atrial fibrillation into ventricular fibrillation and ventricular fibrillation is a non perfusing rhythm, right? That is what causes presumably the sudden cardiac death associated with WPW. So this is the reason that we care about WPW, irrespective of whether or not you have reentrant svt secondary to it. So that's why we oftentimes think of them a little bit differently in terms of our management. So now let's talk more about accessory pathways because I said the directionality of the accessory pathway really dictates what the EKG looks like and what the tachycardia is. So, the first two bidirectional pathways and then concealed accessory pathways are the two most common. The one on the far, right, integrate only pathways, those are pretty rare and you'll see why because of what type of SAS VT they caused. So for bidirectional pathways, again, the pathway conducts both from the atrium to the ventricle and because it conducts A to V, we see WPW on a baseline EKG. But the SVT, as we said, the vast majority of the time actually goes the opposite direction down the A V node, up the pathway from V to A because it's going down the A V node. And using the hyper Kinji system, the tachycardia is a narrow complex tachycardia typical SVT, then you have a concealed accessory pathway. You have no ATRIO ventricular conduction, meaning your baseline EKG is stone cold normal, there is nothing there. It looks entirely normal that SVT on the other hand goes down the A V node, then up the accessory pathway. So that also gives you a narrow complex tachycardia typical SVT. The third option, these are pathways that only conduct from the atria to the ventricle. So that means again because they do that at baseline, we see WPW on the baseline EKG. But their SVT can only go in that direction if they have it, which means it goes from atrium to ventricle, then back up the A V node and no point does it enter the hyper Kinji system? And if you're traveling through the ventricle outside the hyper Kinji system, it's very slow conduction. It's cell to cell to cell to cell. And because of that slow conduction, you get a wide complex tachycardia. So I implore you the next time you're looking at your pal's card, your Pal's algorithm for the wide complex tachycardia with a pulse. There's one little section that says asymptomatic or something like that, like stable, wide complex and regular. And the first thing it will tell you to do is to give a denis and in your mind, you're like, well, if it's VT, why would I give a Dacy blocking the A V node doesn't do anything? And it's because of this rare version of SVT. Could it be antidromic or that's what we call this antidromic SVT, which is a wide complex, regular tachycardia. So it's a fun little thing. The next time you go look at it, that's the reason why that part of pals is present. So, accessory pathways are congenital but not heritable. And of course, I had to put a few asterisks here because there are very rare syndromic cardiomyopathies associated with WPW and accessory pathways. But universally, these have other findings, you're not gonna stumble across one of those. Now, on the right hand side here, this is literally a histologic examination of an accessory pathway. And so this is a trichrome stain. Um The red is the myocardium, the blue is the fibrous valve tissue and you can see that tiny little sliver, right? It's almost shockingly unimpressive like what is it like? 10 cells thick. It's amazing that something so small can cause this much trouble. But essentially, it's important or it's helpful sometimes for families to hear this that it's not something you did during pregnancy. There's no known exposure, drug environmental toxin that we know of that predisposes to accessory pathway formation. It's just pure coincidence, about three or 4% of the population and then about a third of patients and this number varies depending on different studies, up to 90% which feels very over exaggerated to me. So I usually say about a third, a third of patients will have kind of involution of the pathway within the first year of life, sort of scars down and goes away. And that's why if you follow any of our patients, um you'll see that if we start a medication and a newborn around a year of life will oftentimes try to come off of it and we'll see what happens. We'll see if the pathway is still active because sometimes you get lucky and your kid falls into that bucket and then essentially you just watch them empirically and you don't need to have them on a medication. So that was kind of finishing up with a V reciprocating tachycardia. So a circuit that involves an accessory pathway. The second type is a circuit that's essentially inside the A V node and we oversimplify this. Um Obviously, it's not exactly the way that we draw it schematically, but the concept applies. There's still a circuit of electricity that self perpetuates. This is most common in older teens and adults. And in fact, if you're an adult electrophysiologist and someone comes in with SVT, 90% of the time, this is what they're gonna have. A VRT and a VN RT sound very similar, look, very similar act, very similar and they're almost indistinguishable on a baseline. EKG now someone like myself every now and then you get lucky and you can kind of pick one or the other, but usually you're just guessing based off statistics. And the reality is thankfully, it actually doesn't matter. We treat them both exactly the same way. But let's talk about this mechanism. So in about 70% of the population, you just have one road through your A B node, right? You go atrium one road down to the ventricle simple in 30% of the population. So again, it's like a normal variant. That's just out there. They have a second road. And the way I describe this to my families is they have a roundabout. And that makes it very easy to conceptualize how you could just get stuck in the roundabout, right? You can already see how this works where you go down one side and up the other. Now, obviously, it's more nuanced and sophisticated. And um you know, we have very, very original elaborate names for these pathways is one we call the slow pathway because it moves slowly and the other, we call the fast pathway. So the type of reentry can be more complex, but the concept is the same, you're essentially going around and around and around and around until either something triggers it to stop or itself terminates. Now, I just said 30% of the population has this, obviously, 30% of the population doesn't have SVT otherwise, I mean, I'd be generating a ton of RV US and do like a million ablations a month. But essentially this dual a node physiology, that's what we call this the roundabout. There are other features that we don't quite understand in terms of what contributes or predisposes you to developing SVT. So this is the second form of SVT. Again, we treat them the same and we'll talk about that separately. But understanding accessory pathway mediated roundabout, mediated and when I do ablations and I talk to families and I call them and give them an update midway through the procedure. This is literally what I tell them. I said, ah it's the roundabout kind. We're gonna go abate it now and that just makes sense to them. So clinically, it really depends on your age, how you're presenting. And again, statistically speaking, if you're a newborn or an infant, you're gonna be more likely to have pathway mediated a VRT. Whereas on the flip side, if you're a teen or adult, it's more likely to be a VN RT, but it's still a toss up. It could be either for infants. Um, it's important to note they can absolutely be asymptomatic. And some of you might have actually even seen that in your patient panels or population kid comes in for his typical PC P visit. You do his vitals and you're like, oh my God, his heart rate's 220. He looks fine. Otherwise, like, maybe he's a little fussy every now and then. But otherwise it's looking fine. The other symptoms we sometimes see are like just poor feeding. They're not, you know, hungry. Um, if you have more long standing or, um, sort of a heart failure type symptoms that can obviously to poor growth, uh, sudden fussiness or inconsolability. That's a challenging one. I'm sure all of you with kids are like, yeah, that's like every baby. So there's nothing that's like hard and fast about. Oh, this is definitely SVT. And then of course, the concern is that long standing SVT can predispose to heart failure as a child. Oftentimes they're also asymptomatic and typically they don't have the language to describe what they're feeling. One of the things that I commonly hear is kids who are like playing on the playground or at school and then they, they suddenly like, take a break and they walk over to the teacher, they walk over to, you know, a parent and they just lie down on their lap or something that's kind of AAA frequent occurrence that I hear another for whatever universal thing that Children will say in kind of the 3 to 5 age range is my heart is beeping. Um We hear that not infrequently and like I said, because they don't really have the language to describe it. They typically will complain about, you know, nausea or my tummy hurts or stomach ache because again, they understand that and they can convey that in a way whereas they can't really describe to you that their hearts racing teenagers luckily are, I mean, they might not be super verbal, but they can usually tell you if they have palpitations, a racing heart sudden and on sudden off. Um typically they can sometimes tell you like, oh yeah, it happens every time I like bend over and stand up or always during football practice. Um can be associated with dizziness and lightheadedness, sometimes some nausea. Now you don't see here what I didn't list is syncope, right. True syncope. A rhythmic syncope is extremely, extremely, extremely uncommon with SVT. In fact, I'd be very concerned. It wasn't from SVT. That's how rare it would be if you have a structurally normal heart and SVT, that is a perfusing rhythm and it's not a life threat arrhythmia. I'll say it again. It's not a life threatening arrhythmia. So SVT should not cause arrhythmic syncope. Now, you might feel like crap or the, you know, like I said, a baby might not do great if they're in it for days or weeks, but typical paroxysmal SVT should not cause syncope and that should be a red flag that either it's something else or the syncope was caused by a completely unrelated issue. So as the PC P um or sort of primary care provider in any role, um what we really love to kind of partner with is that again, you folks are often one of the first people they're being seen. So they go into the ED, they're diagnosed with SVT and they follow up in the PC P's office two days later. So one of the best things that you can do is really set the tone for what's gonna happen next and kind of do any initial up. And again, this is gonna vary depending on what's available to you in your practice. So again, typical SVT in a structurally normal heart is not a life threatening arrhythmia. And I know that half of you are like, but you said WPW. So WPW is not SVT, right? If you have SVT, that's not life threatening WPW is a separate bucket and we'll talk about that family history. So again, looking for red flags, these rare occurrences where maybe there's something familial, a baseline. EKG super, super important if you're able to get that in your office looking for WPW. Because again, we put those patients in a different bucket regardless of whether or not they have SVT documenting the SVT on a 12 or 15 lead EKG it might seem like, oh, well, you know, the kid came into the ED, it's fine but documenting it on an EKG or an ambulatory monitor is still extremely helpful. You'd be shocked how many times ems doesn't keep the strips and telemetry doesn't get saved in the chart. So, having documented SVT is really helpful. All patients with SVT should have a baseline echo. That's because very, very, very rarely you catch congenital heart disease. I probably do catch it like once a year, right? A kid with mild Epstein or a kid with a loop transposition, sometimes hypertrophic cardiomyopathy. So every now and then you catch one of these. So they should always get a baseline echo and then pending on what you're able to do in your clinic getting as much done as possible before referring them again, just helps expedite a lot of what we need to do. But anyone with SVT, it's certainly reasonable to refer to electrophysiology. Don't feel like you have to bypass and go through cardiology first. Um We are in a resource rich environment and you have the luxury of having an electrophysiologist. So it doesn't necessarily aid in um conversations with the family to have another in between person. So some red flag symptoms. I mentioned that these are some of the things you're looking out for in either the family or the personal history. Um And this is what's gonna take that typical SVT patient and put them in a slightly different bucket for you to say. Actually, I can't do all of that very classic reassurance. We're gonna get you in to see ep slightly sooner. So, any form of structural heart disease, right? That's a no brainer. Um, obviously any family history of sudden cardiac death or sudden death, less than 40 suspicious death. This one's a little harder because like, it's fine to, um, like oftentimes we will err on the side of being like, well, I'm not really sure what happened. It makes sense to refer them and that's entirely reasonable. Uh true syncope, right? Actual loss of consciousness. That doesn't sound vasovagal. Absolutely. That's a red flag and be careful here. Not presyncope, not, I felt like I was gonna pass out, not, oh I felt lightheaded or I got dizzy. Those are not syncope, right? A rhythmic syncope, you lose consciousness. Um And then if it's always a wide complex tachycardia. So again, we talked about wide complex rhythms can be SVT and in fact, statistically speaking, most of the time they are in Children, but it's not impossible to have VT um literally just this last week, a friend of mine um who's an electrophysiologist in Tucson. He had a patient who, a newborn who got referred to a wide complex rhythm and got like 16 doses of adenosine and got shocked like seven times or something. Um It was VT the whole time. So that's not surprising that it didn't respond the same way we would expect SVT to. All right. So management, um again, this comes down to the two buckets you either have WPW in your baseline ECG or don't if you have WPW, you should be referred to EP. And in my opinion, you should be offered an ablation. Always again, that's because of the sudden cardiac death risk, not because of the SVT. If you do not have WPW, you do not have the sudden cardiac death risk, you have the risk of the general population. So at that point, it really comes down to symptoms. How bothersome is this? How often does it happen? Are you going to the school nurse all the time? Are they leaving school to have to go to the ed? Are they afraid to do activities because they don't want to stimulate it? That determines which of these three things and they're not mutually exclusive. You can start with one and go to another. You can also go straight to ablation. I think sometimes people feel like, oh, well, you have to fail another intervention before you get a procedure. That's 100% not true. And in fact, most Children, especially teenagers do not tolerate the medications that would be first line. Those are beta blockers, particularly teenagers, they have a lot of mood effects and um, fatigue and malaise and it just is very, very challenging for them to take a beta blocker. And so it's not unreasonable, even if it's just a first time SVT episode to offer an ablation to a patient. All right. So this, I thought would be a little bit fun for you to just think about kind of what you've learned, what you've been told over the years, that different things because these are things that come up all the time for me. So, um, patients with SVT need to be restricted from exercise. So, no, the answer is no. And again, I didn't say WPW, I said SVT, right. So these are patients who have a normal EKG who have SVT, it is not a life threatening arrhythmia. Now, if they say every time I go to football practice, I get SVT then yeah, they probably shouldn't do that for right now and they should probably just come in for an ablation, but there is no increased risk of arrhythmic death or cardiac events. Um If a parent has or had WPW, then the Children need to be screened for WPW. This is also false. So again, there's no heritable component outside of syndromic issues. So we don't routinely recommend screening unless a patient has symptoms. So if your kid starts complaining about uh palpitations, then absolutely, they can get an EKG but we don't routinely do it. This comes up a lot of times like in the nursery, we get these patients that are discharged from the nursery to cardiology to get an EKG because like mom or dad had a, um SVT or WPW. Um, if you have WPW but have never had SVT, then you don't need an ablation. Hopefully, this has come across to you. Now, these are kind of um related but separate entities, the sudden cardiac death risk is independent of whether or not you've had SVTWPW, by definition, it's just the antegrade conduction that is the cardiac death risk. So, it is not true. You can have Baseline WPW, never have SVT and still warrants an ablation. All right, I'm currently gonna turn a lot of heads with this one. Patients with WPW need to be restricted from exercise. So I'm telling you, there's a sudden cardiac death risk with WPW. And you're like, well, yeah, of course, we restrict from exercise that is also probably false. And the reason I have to say probably here is we'll never be able to do this study. But the recommendations, even the most recent recommendations which are sadly from 2012, right, the HR S which is the Heart Rhythm Society Pace Society. The last WPW recommendations were from 2012 which is wild. But even those did not have a blanket statement to restrict. Since that time, we have much more compelling data to say that your risk is probably not increased with activity. So this was the largest pediatric WPW study ever performed. Multi Center International took about 800 patients with WPW and then about 100 patients who had WPW and a life threatening event kind of compared them to understand what happened here. Are there any risk factors we can pick up? And a few things are um were found. So, um the life threatening event. Oops, sorry. Um The life threatening event was the Sentinel, meaning first presenting symptom in over 65% of the patients. That's crazy, right? So that means that these were not patients who like, oh started with syncope and then developed more syncope and then died. No, they had a life threatening event at their presenting symptom and six of those patients with a 96 it was death. 37%. We as electrophysiologists called them low risk on an EP study, which means that we told them you're not at risk for having anything bad happen. I'm going to leave this pathway and then something bad happened 37%. What that means is we're not good at determining who's low risk. On the contrary, we're actually quite good at telling who's high risk. So if you are high risk on EP study, you're high risk. If you're not high risk, we actually don't know what your risk is, but it's definitely not zero. And then finally, the vast majority of patients had events at rest or with noncompetitive activity. And again, this keeps coming up again and again and again, in all the studies, there was a large study on hypertrophic cardiomyopathy patients that was recently released in May of 2023. That again throws in the face of this idea that patients need to be restricted because physical activity increases the risk of a sudden cardiac event data does not really support that moving forward. That's not to say that I'm like, yeah, tell everyone to go to their, you know, division one NCAA swim team. That's fine. No, it just adds more weight to the idea of take the WPW off the table, refer them for an ablation. Then the risk goes back to that of the general population. All right. Um So uh how old does the patient need to be to get an ablation? This comes up a lot too. There's like a lot of misinformation. I just had a patient um the other week where they were told that they needed to um go to college before they could have an ablation. Um The answer is uh about 25 kg for an elective procedure. Now, obviously, we can do procedures at any age for any clinical indication when warranted, but the benefits of waiting are not there above 25 kg, meaning the bigger you are that it's not safer and it's not more effective. So we're able to do safe and effective procedures, patients 25 kg and higher. So just, you know, for reference, that's probably when they're getting to like 78 years old. That's typically when we say, yeah, this is a perfect time to do it. Um It can also be later. Of course, too. Um, patients with WPW can't get a denine, right. This comes up a lot again, because of the miscommunication between atrial fibrillation and SVT. So if you are an SVT and have a narrow complex, regular rhythm, you should absolutely get denine. Now, if you're in an irregular rhythm, that's wide complex, that could be atrial fibrillation and that we would say no, we don't want to block the A V node because then we're gonna shuttle all of that fibrillatory activity down the pathway since we can't go down the A V node anymore and that can be dangerous. Um Patients need to fail a medication before getting an ablation like a beta blocker. This is another kind of not true statement. You can go straight to an ablation if you need to. Um this one comes up a lot caffeine chocolate, things like that. If you um take, you're not allowed to take those because um it'll cause your SVT. Now, granted, I'm not advocating that Children get lattes or anything like that, but the degree of caffeine in both coffee, tea and chocolate is not ever been shown to be associated with significant SVT. Now, if your patient said, well, every time I get a latte, I get SVT, well, then yeah, for that patient, they probably shouldn't have it. But statistically speaking, it doesn't increase your risk of SVT or increases sudden crave death risk. Um And then if you have SVT or WPW, you can't take a DH D medications. This is a very, very common one. also there's never been any compelling data that suggests that a DH D medications increase your risk of a sudden cardiac event. Now, I know the FDA did put that warning on all of the methylphenidate products, but they just didn't have enough data to say that's the case. The Heart Rhythm Society, the PA society have never supported like universal screening of a DH D patients to look for WPW. And um additionally, there's never been any compelling data to actually support the idea that it increases your risk. And what we never want to do is we don't want to take a theoretical unbased, unsubstantiated risk and put it above the kid who's actually at risk of failing fifth grade because of his A DH D, right. We want to treat the A DH D. So, you know, I know that lots of times depending on where you practice, there might be, oh, we need to get cardiac clearance before XY and Z happens. Um You know, you need to do what you need to do to help you like sleep at night and take care of patients well, but the reality is that the risk really um doesn't come out of uh fruition in the data. OK. Very briefly, Bradycardia and XP, luckily, um there's not much to say for either of them in a really good way. So if the bradycardia sinus and the patient's asymptomatic, it's almost always benign because remember really the only intervention we have for Curia is a pacemaker. So unless you think the patient needs a pacemaker, like there's really not much else we can do. So, um the important question is, are they symptomatic? If they're symptomatic, then yeah, they should come to ep urgently and we should assess whether or not a pacemaker is the right decision for them. Rarely symptomatic, bradycardia can be associated with inherited arrhythmia syndromes. And again, that comes down to taking a really good family history. Um We'll talk about that at the end. Um And that's another place where again, the primary care provider really uh inserts him or herself into our uh workflow. If the patient is not symptomatic, then really the decision tree is, is it sinus or not sinus if it's sinus, which is 95 plus percent of the time. The question is, are they able to have normal heart rate responses when they need it? So, Children, particularly teenagers and teenage boys have a ton of vagal tone, right? I read hundreds of EKG S and Halters and Z OS every week. The vast majority of them have a heart rate that goes down into the thirties overnight. It just does, it's ok. And the reality is what I wanna know is when they go to exercise, does their heart rate compensate? So sometimes what I even do to make families reassured is in the clinic, I'll make the kid run around, do some jumping jacks, do some push ups, redo the EKG and prove. Oh, that's a normal sinus P wave. And your heart rate jumped 3040 points totally fine. Now, if it's heart block and they're asymptomatic, which again, most of the late onset ones are, you've probably even had patients in your clinic. Same thing they come in for an unrelated thing, vaccine, whatever PC P world child visit and you check their heart rate and it's 45 and then you're like, oh crap, you do an EKG and they're in complete heart block. Um that does require an ep referral but doesn't have to be urgent because the patients asymptomatic as they usually are um roll the PC P here a lot of the same things. So, reassurance, family history, the baseline EKG again to determine sinus versus heart block, looking at the ambulatory rhythm monitors for heart rate variability because again, that's what matters. Some of these patients will need an echo or an exercise test. And again, depending on what you have available to you in your clinic, that may or may not be possible prior to referral and then referring any patient who's symptomatic or kind of has any red flag symptoms, ectopy. Um kind of the same story hardly ever symptomatic in the sense that it's not causing real problems, although the patient might feel it and it's almost always benign and the natural history predicts resolution the vast majority of the time. So PAC S, we don't really do much to. Um we very, very, very rarely need to treat any of these things. Um They can under certain circumstances be associated with some structural heart disease or inherited arrhythmia syndromes. Again, that's gonna come down to, are there any other symptoms? Is there anything on the physical exam? PV CS was slightly different in the sense that there are rare associations of PV C burden with development of LV dysfunction. So, this was a study we actually did in Boston where we took about 200 patients to normal kids who had PV CS and we looked at kind of their PV C burden and their EF and essentially what we found is that the vast, vast majority have completely normal function, very few ended up below this lead red line. Only one ended up below 40 which we call significant dysfunction and that patient had a PV C burden of 50 some odd percent. So, um those patients uh with PV C burdens above like two or 3% should probably be followed by a cardiologist just to assess for their function over time. So same thing here. Um Reassurance Family History Baseline EKG that helps us localize the PV CS um as well as the PAC S kind of where they're coming from and there are typical locations. And so if it's falling outside the typical location. Sometimes it's helpful to know that it gives us a little bit more sort of perks. My spidey sense a little bit um ambulatory monitoring again to look at the burden. So how many PV CS are you actually having percentage wise over a period of time? Um again, echoes for some of these patients to assess for either structural heart disease and to monitor function. And then another nice thing to do is um, exercise test. So ectopy should be suppressed at higher heart rates. And again, it's another sort of tick box to say this is following in the quote, normal, typical P bucket as opposed to something that's a little bit atypical. All right. So for the last kind of 15 minutes or so, we're gonna do some EKG S which I thought would be really fun. Again, this is not meant to be, um I'm not like testing anyone not gonna call on anyone. It's really just to go through it. Look at it, think about what you see, how you would interpret it and what things you think are important or not important. So I'll leave it up on the screen for just a minute or two or not even that a few seconds. And you might be like, well, without the context of the age and the history, like, yes, but what I'm really trying to point out here is that these are really can't miss EKG S at any age So this one is WPW and fairly obvious WPW hopefully in a good way. And the reason I picked an obvious one is because it highlights some of the features that can be more helpful when you're looking at the subtle ones. So again, you look for the classic short pr wide QR s. Again, that's that delta wave. And then another key feature which we sometimes forget, which is a nice little tip is an abnormal T wave. Anytime you have abnormal depolarization, you're going to have abnormal repolarization. So these T waves are wonky and T wave inversions like this and one in a VL, it's completely not normal. Another good feature is if your QR S axis is like very atypical for age. So most kids are gonna be between zero and 90 babies are gonna be between 90 you know, one twentyish, this is a very leftward and superior axis, which would be extremely atypical for an otherwise healthy kid. And then the last feature which is a nice one and very helpful for subtle preexcitation. The way that your septum depolarizes is actually from the LV towards the RV. And that's the first part of ventricular depolarization. And what that leads to is a tiny little negative Q wave in the lateral precordial leads five and six. And so when you lose that Q wave, that can be a subtle sign of preexcitation. So it's a good thing to look for. If again, you have suspicion that a patient might have WPW or preexcitation. All right, here's the next one. There are a couple things abnormal about this, but it really highlighted one important feature, which is probably one of the few rules, if there's one takeaway from today, this is the one hard and fast rule that you will always be right if you do. And that is T wave inversions in the lateral precordium are never OK for any reason at any age. So they always need to be referred. So what do I mean by that? I mean, T wave inversions in V five and V six. Now, obviously, this patient has T wave inversions in other areas and kind of you might, some of you might have looked and be like, oh this is ST elevation. Um I don't really want to focus on those. If you see T wave inversions in V five and V six, you should send them to a cardiologist doesn't have to be ep but they need to see someone. Um Again, it doesn't matter how old they are, it doesn't matter what the situation is and the reason is yes, there's a subset of patients in which it could be transient. Like those coming into the ed who have electrolyte disturbances because they've been vomiting with gastro or um some kind of like athlete hearts and certain ethnicities might have this but they a very, very high correlation with cardiomyopathy and T wave inversions in the lateral predi All right. So this patient actually is a normal otherwise healthy kid. Um actually has a normal echo, but this is his EKG and this was the first sign that he actually had a cardiomyopathy before we even saw anything on his echo. All right. Um This one, so this one also has T wave inversion. So that's not the finding here, but just take a minute, there's a coup there. I mean, there's, there's an abnormal EKG. But um the thing I wanted to draw your attention to mostly with the profound QTC prolongation. So again, T wave inversions in the latter precordium abnormal, right? Another thing that was abnormal is the QR S is kind of fractionated and wide. And then the P wave is actually quite broad and wide. There's probably some bi atrial enlargement here. But this kid was in the pu and we called them and we said, hey, he's got profound QTC prolongation. We need to stop all non essential, non life saving medications that can prolong the QT. And they were like, yes, absolutely, definitely. And they did except they forgot to look at the PR N medications. So this kid kept getting 24 to 6 hour hydrOXYzine, which is like a Benadryl, you guys probably use it more than I even. Um and it can prolong the QTC. And 12 hours later, I got called by the cardiology fellow and she said, hey, you know that kid in the PQ. And I was like, oh, he went into torsos and she was like, yeah, how did you know this is actually him 12 hours later. So he ended up having Torsades de Po, which is the arrhythmia associated with QT prolongation. Now, luckily it was short lived and self limited, but it was very, very um predictive that this was gonna happen at some point. So again, don't underestimate the dangers of QT prolongation. All right. Final kind of can't miss EKG. All right. Um High grade A V block. So I didn't say third degree heart block here because it's a little bit more nuanced than that. But it's the idea that there's a v dissociation and heart block here and the things to look for are gonna be a variable pr interval, non physiologic. Pr an important component, the atrial rate is faster than the ventricular rate and the cure us without P waves. And so this sometimes can be subtle if the junctional or escape rate is pretty profound or, or um robust. And so if you don't look closely, sometimes you might miss these. Again, these kids are almost always asymptomatic but they should be followed. All right. So now, some normal variants, we're gonna um these ones don't kind of have the uh the test part of it. They're just important to know. So, sinus bradycardia, we already talked about that in the bradycardia section. If it's sinus and it augments with um, some type of activity, it's normal. This patient also has a little bit of sinus arrhythmia. If you just sort of step back and look at it, the Q RSS are a little bit closer here than they are over here again. A normal finding a terrible name. Um, we really should just refer to it as, um, resp variation because that's essentially what it is. It's normal changes in your vagal tone when you breathe, it's 100% perfectly normal in healthy Children. And I'd be more concerned if it wasn't there. Um Another thing is you can kind of have an exaggeration of this where your sinus rate slows so much that you actually develop junctional rhythm. And this is probably a junctional uh a combination of junctional and low atrial. And it's the same concept in that we're changing the shape of the P wave. The pr is super short and the difference here, unlike with heart block where the atrial rate was faster than the ventricular rate. Here, the ventricular rate is faster than the atrial rate and it corresponds with sinus slowing. But when the sinus rate picks up again, you conduct just fine. So that's how to differentiate between, is it heart block or is it just junctional rhythm? And then again, this is just a slide to sort of highlight the differences here. A V block implies that you cannot conduct from the atrium to the ventricle. So by definition, the atrium must be going faster. If the ventricle is going faster than the atrium, then it never gets an opportunity to try to conduct. And so that's kind of how you differentiate here. In this scenario, the ventricular rate is faster than the atrial rate. So this is junctional rhythm, whereas in this scenario, the atrial rate is actually faster than the ventricular rate. And that means there's some component of heart block. Um A low atrial rhythm is just another kind of escape rhythm common in patients, teenagers with increased vagal tone, as long as you have a physiologic rate, a low atrial rhythm is perfectly fine. And another tip make this kid do some jumping jacks repeat. The EKG prove that the sinus P wave comes out, meaning that it's upright in 23 and a VF and you'll look like a genius in front of the family. And then this one nocturnal wanky box, this is extremely, extremely common. So this is actually again one of those scenarios where I would more commonly see it than not. So Children, especially teenagers have a ton of vagal tone that gets uninhibited at night. And they oftentimes will develop wanky bach or Mobis one. And you can tell because the pr interval here is shorter than the pr intervals right before the draft beat. And then the other key to wanky B is the return beat, meaning the first conducted beat after is also has a short pr that's gonna be the hallmarks of how to determine its wanky b, as long as they do this in the middle of the night, it's perfectly fine. Even though I'm sure you're like, oh my God, a heart rate of 24. That's crazy. It's not, it's normal. Ok. All right. Last minute is just to plug my other job, which is inherited arrhythmia syndromes. So we pump them into channelopathy and arrhythmic cardiomyopathies. So, channelopathy are just, you know, mutations and typically ion channels. Whereas the arrhythmic cardiomyopathies are more structural or um they can be metabolic proteins. This is not meant to be a particularly educational slide other than to point out how complex the heart cell is and what different things can go wrong to cause an arrhythmia syndrome. So the reason that I like this slide or that I made this slide is because I want to reinforce that this could be someone's entire day job and entire career inherited arrhythmias is so complex. So nuanced and so siloed that having the ability to understand and having the experience to manage these patients is a job in and of itself. And I want to kind of reinforce that it means you should try always to send patients to a specialist where they focus on this thing and not just a general cardiologist or a general electrophysiologist. Even there are many people who think like, oh, well, I, you know know what DNA is, Ergo, I am expert in genes and genetics, which is just sadly not true. Um, understanding these uh diseases and of course, the rarity of them, it builds your experience and knowing what you've seen before can only happen if you've seen a lot of these patients. Um, the red flag symptoms from an inherited arrhythmia standpoint, most of these, I'm sure, you know, and are already looking for, but it's nice. There are a couple features that are helpful. So any sudden cardiac death below 40 particularly in first degree relatives, suspicious death. This is a nice way to ask the question differently. So anyone who died, swimming, drowning, water skiing, uh sleeping, single car accidents, right? Like they went off the road, but there was like no snow and nobody knows why or someone who died from seizures and then any family history of frequent people with seizures, sensor, neural hearing loss that's associated with Long Qt syndrome, frequent syncope, particularly in adults. I just got referred a patient a couple weeks ago where the dad had like 30 year history of recurrent syncope that they kept saying was vasovagal. You can't be an adult and have vasovagal syncope that frequently. Um arrhythmia is less than 40 or then multiple members in the family who have pacemakers or IC DS. And then really what we're doing is we're providing kind of comprehensive evaluation that includes diagnostics, genetic counseling and genetic testing that is all done through a certified genetic counselor. So one of the other things I always harp on is that genetic counseling has to happen before genetic testing and genetic testing can't be treated like a chest X ray. There's a lot of important information that needs to be disclosed to a family before they agree to and consent to genetic testing and having people trained to do that is very important for education. We provide personalized slide decks that actually go through their family history. The actual gene change, the protein change. What's been published about it? What vitro and vivo studies have been performed? Has it ever been published in large databases? Things like that. And then we're able to coordinate cascade and family screening. Um because we collaborate with the adult hospital and we have a weekly adult and pediatric cardiovascular genetics conference where we discuss all of our patients and then finally personalized and evidence based medicine. Again, like I said, this is someone's entire full time job. And so having someone with experience of what does this data show? What evidence is actually out there? What are the new trials like a lot of this stuff isn't necessarily public knowledge, you just know, oh, they're doing AC R DS trial up in Vancouver, we can talk to them and maybe get our patients in. This is where it becomes really helpful to the families. All right. So last slide um couple take home points. So typical SVT again, in the typical bucket is not a life threatening arrhythmia. Hopefully that comes across and really one of the roles of the PC P is to help set that tone for the family because it's terrifying. Right. It's a terrifying diagnosis. All patients with WPW again, this is not the SVT are at risk for sudden cardiac death, regardless of whether or not they've ever had SVT. So it's a different bucket, a different process and they all should be referred to an electrophysiologist, Bradycardia and sort of ectopy are rarely symptomatic are hardly ever required intervention. PV CS. Typically, we follow just expectantly to assess for LV dysfunction which is extremely rare. EKG findings that should always prompt a referral WPW lateral T wave versions, QT prolongation and high grade A V block. And then those that again, little asterisk probably don't require a referral, but maybe some additional evaluation, sinus, bradycardia, sinus arrhythmia, and then all of the consequences of vagal tone, low atrial rhythm, intermittent junctional and nocturnal wanky block. And then really the family history is kind of like the, the gateway to how we determine whether or not someone's at risk for an inherited arrhythmia syndrome. And that's really where the PC P comes into play in sort of peeling back all those layers and taking a really thorough family history to determine who needs a referral and who doesn't. So this is just um the referral page. Um I will say that sometimes the access center has a little bit of trouble getting in touch with. Ep just because we are a very niche group. So always feel like you can contact them or contact us directly. So that's my contact, you can email me and then Britney Ojeda is both me and Ron Tanel scheduler. So you can contact her via email or call the office or send information facts. And again, like I said, in the beginning, I take it seriously if you guys have a kid who comes in, you get an EKG and you're like, well, you know, Karen said this was probably normal. Uh but I'm not really sure, shoot me an email, right? I usually get back to people in a day or two. None of these are hardly ever urgent. If it was, you'd send them to an ed. So, you know, it can just help you build your repertoire and your experience and feel more comfortable to like make those decisions in the future. Great. Thank you. Sorry. That was a lot. That's OK. You have and we're gonna share the slides in your email with the attendees too. You have a couple questions in the Q and A. You see those uh Yeah, let me just pull this up. Ok. Um uh The most common side effects of propranolol. Uh Great question. So you, you and you probably see this a lot as the most common um medication we use and that's for multiple reasons. One because we have a ton of experience using it over the years. It's been well established in terms of safety and efficacy. Two, it has really um predictable pharmacokinetics. It has a wide therapeutic index and some of our other antiarrhythmics, it has more narrow therapeutic indexes. So we worry about toxicity a lot more. Um for neonates and infants. It's rare but it can cause hypoglycemia at initiation and that's why all babies should be initiated on propranolol while in the hospital. That's just a um a sort of personal belief I have. That was what I was trained to do. That's what I've always done in terms of toddlers and school age, Children, hardly anything. I mean, sometimes they don't like the taste and so they spit it up. Um in terms of the effects on heart rate and blood pressure at the doses we're using it is I, I mean, I know this comes up a lot in the nicu don. I think it is bradycardic. But if you really compare, I actually did a study like this when I was in Boston, we actually compared pre and post for Pran IOL. There is no statistical difference in terms of their heart rate, blood pressure, cardiac output, anything like that. All right, do kids with congenital heart disease? Um uh Great question. So there are definitely certain forms of congenital heart disease that are more associated with arrhythmia, including WPW like accessory pathways. That is Epstein's anomaly hypertrophic cardiomyopathy. A looped transposition hetero taxi syndromes. So yes, those patients um are at higher risk at baseline for having the substrate. Now, whether or not they have the SVT that is related to the trigger. So you have the physical pathway, whether or not you activate the SVT is the trigger component of that patients with congenital heart disease for sure, because they have more scar in their heart. Um They're on medications that typically affect their electrolytes. They are technically at higher risk. We don't include those in everything I talked about today. Um Meaning that I don't trust a congenital heart kids svt the same way I like, you know, kind of not dismiss but I don't, I don't worry about as much kind of a kid with a structurally normal heart. It's a great question. So two families is a pacemaker and a healthy child referred. Um uh uh it depends on kind of how close they are in the family. So I would say first degree relatives, maybe if it's like on the same side, like it's dad and dad's brother. Yes, I think it's fine to um refer them non urgently. You, you're asking, I'm sure a great question of like at what age because most of these inherited arrhythmias are not manifesting in childhood period. Um I think what I typically would tell families is if you have that family history and um you know, the, the kid is small, like less than five years old, usually we'll do a first kind of evaluation, just do a baseline EKG, do a baseline echo. And again, that's typically mostly for reassurance for the family, then we would follow them. I don't know every twoish years, something like that to assess for whether or not there's anything moving forward. The more important part of that is getting the parent or the, the pro band, the person with the actual symptoms to determine if genetic testing is warranted in that person. So that's where it's helpful. Me being a component of the adult group as well, being able to go to Vasantha Danta, who's my counterpart on the adult side and say, hey, I've got this family. Dad's got a pacemaker, his brother's got a pacemaker. Uh grandma's got a pacemaker. Can you see them and determine if there's something there that we need to test for? And then we can use that information to see if the Children need to be tested and if the parents want the Children testing. Um what is the average age? Oh, great question. It's older. So um it increases it, it um compounds on itself over time. So events in Children are exceedingly rare. The youngest patient, um uh the youngest patient we've seen die. I think in that study was less than seven. There are definitely infants who have been um reported as having kind of arrests secondary or presumably to WPW because that was the only thing that was found on their evaluation, but the risk of atrial fibrillation increases with age and that's really where the risk of sudden cardiac death comes in. And that's why, you know, you've probably heard the adage like, oh, if you've got WPW, you shouldn't block the A V node, right? You shouldn't give them a Dacy and then you come to us and we're like, put everybody on a beta blocker. And that's because the risk of pre excited atrial fibrillation below the age of like teenage years, like, let's just say 12 or 13 is exceedingly exceedingly exceedingly low. Meaning that I have no concern putting that type of patient on a beta blocker with WPW. Now, when you get to become a teenager, that's when we start to say your risk of pre excited A FB starts to increase not insubstantially. So that point, I would say we definitely should ablate you and, or we should think about switching you off a beta blocker. Um Would you say that even a team of finding um shouldn't. Uh So I would say uh no, II, I would not restrict a team with WPW um from competitive sports. What I would do is I would say you should just have an ablation because that will take this entire question off the table. So even if they don't of SVT and they just have WPW and especially if they want to play sports and the, you know, people are nervous about that. We get that referral all the time. But statistically speaking, there's no data to support that athletics increases your risk. Now, that's statistically speaking, that doesn't mean that you could be the one kid where, yeah, actually it triggered your arrhythmia and you had a terrible outcome. So that's why I universally recommend if the patient is big enough and healthy that an elective ablation is really the best way to manage that. So they don't have to worry about it. Great. Thank you. Yeah, those are all great questions. Thank you so much for speaking today. Everybody. We hope you have a great end of your year and holiday. We will see you all in 2024. We will share doctor Austin's contact informa information, her slides also by the end of the week and again, thank you. It was a great talk. We really appreciate you speaking today. Have a great day, everybody. Created by
