Okay, welcome everybody. This is our core panel that's going to discuss three cases. For those of you who've already listened to the core concepts, you've heard four excellent discussions on the concept of Tetralogy of Flow from sudden cardiac death, risk stratification to atrial arrhythmias to conduction system pacing to ventricular tachycardia ablations. And today, to sort of pull it all together, we're going to go through three cases that I think hopefully will shed some light and spark some discussion moving forward. So this first case is a 32-year-old patient with Tetralogy of Flow, presents with increasing exertional fatigue for the last couple of years, is a New York Heart Association II. The initial surgery was that of a BT shunt at three months of age and complete head repair at two years of age with a transannular approach. The patient has no history of syncope, has some rare palpitations, and ulcer monitor that for the most part looks pretty normal with some rare PVCs and rare couplets, but no non-sustained VT. The most recent echocardiogram has moderate tricuspid regurgitation, severe pulmonary regurgitation, mild RV dysfunction, and moderate RV desynchrony. The MRI has an end-diastolic index volume of 155, an ejection fraction of 45%, an LV ejection fraction of 49%, mild RV scar, and about 10% gadolinium. And the exercise test has a VO2 peak of 20 with just some single PVCs. This is the EKG that looks like sinus at about 58 beats per minute with a QRS duration of about 191, right bundle branch block, and a little bit of left axis deviation. This patient is presented at CAV conference, and the interventional cardiology colleagues are rushing ahead to get the pulmonary valve put in. But as the electrophysiologist in the room, you're sort of asked, is there any additional testing that you would like to do before the placement undergoes a valve or maybe even after the valve? And so to start us off with this discussion, we're going to let Anne Dubin from Stanford take the lead on this. And both Jeremy Moore from UCLA and Natasha de Groot from the Netherlands certainly can chime in with any comments after that. Thanks, Mitch. I think there are two big issues in this case. Number one is the question of when you have an interventional cath person deciding that they're going to go in and place a valve, a transcatheter valve in place and potentially limit your ability to access the right ventricular outflow track in the future as far as the potential for ablation. And number two, this patient is already starting to show some signs of RV dysfunction, low normal LV function, bordering on LV dysfunction, and indefinite to synchrony with a very wide QRS of 190. And so I think maybe we should take each of those things separately. And I'm going to be curious what my co-panelists have to say as well. Where we are, probably how we would approach this patient is at the beginning of the catheterization before the actual intervention, we would actually map out the infundibular area to look for circuits. And if we found a circuit there, we'd probably do a prophylactic ablation at that point. This would be a little bit controversial. This patient has not had ventricular tachycardia, has only had single PVCs. But this is our only chance to really get in there and see that area before that area is lost to us, secondary to the valve. And so whereas we might not, we probably would not do a stem study per se. I think we definitely would do some mapping to look for circuits at that point and tissues. Maybe we should start with that and see what everybody else would do and then we can move on to the conduction system. Jeremy, I know you sort of have been a big proponent of this approach. Yeah, so I would totally agree with what Anne just said. And that is that there would be concern that once that valve goes in, we could lose access to the areas. And those are the areas that the valve covers are the exact areas that are implicated in monomorphic VT in the TET population. So I think it's a real concern. In this particular case, there is some ventricular dysfunction at least, which makes me even more likely to want to do that because that does pose some risk for future VT. But yeah, we would go in and we would map those areas like she said. We typically do program ventricular stimulation just to see if there is an inducible VT. I think it's nice to know that. It does take extra time. Just doing the VSTEM can take you up to an hour or so to do all of the different protocols. But you know, if that's what we would do and then if we found any slowly conducting anatomical isthmus or inducible VT, then we would ablate the areas that are implicated in that. Good. Natasja, anything different like you might do in Europe? No, we also do the same. The problem is that we cannot identify patients who are at risk and this is your only chance. So what we would do is we would also do an EB study and try to induce the VT. It's just for your own comfort. There's no scientific base for this, but it's just that if you have an induction of VT, it just supports that you did the right thing. So we would definitely go for mapping in sinus rhythm and looking for the slow conduction zones. So, Ian, let's take it to the next step. Let's say you do all that and there's a little scar, but there's no really slow conduction velocities. Everything looked good, especially across isthmus three, and you're pretty comfortable with it. And your cath person puts a valve in and that goes well. You know, three, four or five, six months down the road, the patient still has some level of exertional fatigue. There's still some to synchrony. How much you approach that patient at that point, then? I thought you were going to say. You have a lot of time for remodeling, let's say. I thought you were going to tell me that they put the valve in and suddenly they're having runs of VT, which is also very common. I thought you were going to say that too. We can take that as the second question also. And there's a whole other area to discuss at some point. But going with what your scenario was, I think we tend to be a bit aggressive here. I think this is a patient who is right on the borderline right now. And we probably would consider some kind of resynchronization or conduction system pacing, I should say, in some way, shape or form. And probably nowadays, the way we would approach this is through true conduction system pacing, trying to target the His bundle. And try and really get His pacing in this patient to see if we could improve not only the synchrony issues, function. But as we've shown, we can actually decrease mortality through this. And so for those reasons, I think that I am more likely to pull the trigger a little early. I think it is an extremely powerful therapy in heart failure that we haven't really started taking full advantage of yet in the pediatric and congenital heart disease world that we need to. So we would aim to try and put a pacemaker in the conduction system area. Okay. So let's take the first part of the question that I think you and Jeremy thought I was going to go to. But let's do that. They put a valve in. They've got a nice harmony valve in. They're happy with the result. And the patient starts having salvos of non-sustained VT that look monomorphic. You know, they've got a left bundle inferior access. Let's say they're coming from up there. Is it just a little bit of irritation from the procedure? Are you going to put them on medications? Are you going to put a loop recorder in? Are you going to go back to the cath lab? A whole bunch of different ways to scale this. But I'd be curious what you think and then what the other Natasha and Jeremy think as well. Yeah. I mean, I think this has been the thing that's kind of kept us up at night because the vast majority of these patients, even with runs of VT, which you do see, and it tends to be mechanical and it goes away within the first two to four weeks. Just fine. But I do know there have been two reports of patients who torsaded immediately in the first 24 hours following one of these valves. So it brings your blood pressure up a little, is what I'll say. What we tend to do is if we see somebody with a high burden of ventricular ectopy and runs of non-sustained VT monomorphic or they're 99% monomorphic. We will watch them. Usually we keep them overnight, as you tend to do with these valves. We may keep them an additional day just to see if we can get it to cool down a little bit. We will treat them if there isn't a high burden with lidocaine initially, and then we move them over to a beta blocker. And we keep them on beta blocker for about two to three months and then take them off. Now, is any of this shown to be effective? Is any of it worthwhile? No one's shown any of this. And this just, as I said, it's to bring our blood pressure down more than anything else. And I'm really curious what Natasha and Jeremy would do in their institutions in that scenario. And you too, Mitch. Yeah. Jeremy, Natasha, what are your thoughts? Yeah. I mean, I guess the timing, I think, like Anne said, I think the timing is what's key here. I guess if this is the first few days after the valve goes in, I think it's to be expected. And we would watch it. We put all of our patients actually these days on propranolol, just prophylactically. But if there's a high burden of ventricular arrhythmia, we sometimes will be even more aggressive with, you know, maxillotine and other drugs. But I think it's the timing. If this is an immediately post procedure, it's to be expected. I would expect it to just run its course, get better with time. I think the Stanford group and others have shown that. But if this is like months later, I would potentially be worried about something else going on. You know, potentially even maybe of a new circuit that's been maybe some other isthmus that's now more active than it was before. So it might even warrant an EP study if this is months or a year later or something. But it just depends on the timing, I think. How long do you treat for, Jeremy? How long do you keep them on beta blockers? We typically do six weeks is our practice. That's what we did. I had one recently after a Harmony valve and I did what Ann did. I kept them a couple of days in the hospital, put a loop recorder in them, sent them home with a beta blocker. And they continued to have stuff even a couple of months later. And I brought them back to the lab and then couldn't start anything in the lab. So I think this is a hard group to really know what to do with long term. And I'm not so sure we really know what it means long term yet. But I do think we have to follow them. Natasha, any other thoughts at your end? No, we also bridge with beta blockers. Sometimes if they really have frequent runs or frequent ectopy, we also do a halter monitoring during the follow up period. And in general, we're also more aggressive in going early to the cath lab for an EP study. Have either or any of the three of you ever found the EP study to be positive in that scenario? Following a valve placement when you did see a lot of ectopy? The only time I've, we have a, we're actually doing a study currently. So I've got some inside information. I've not seen that personally, but one of the centers that's involved in a study we're currently doing did see a re-entrant VT. There was a patient who actually was negative initially. But after the valve went in and had a VT substrate, it was inducible. But presented with frequent non-sustained VT, which prompted the EP study. And had that immediately post the valve and then that just continued? I don't know if I know that much granularity to the story, but I think it was ongoing as an outpatient is what I understand. Interesting. Interesting. Great. All right. Any other comments on this case? All right. Let's move on to the next case. Okay. So this is a 49-year-old patient with Tetralogy. Presents with increasing dyspnea, rapid heartbeat. Had initial VT shunt at two years of age. At six, developed increasing hypercyanotic spells. Underwent a second shunt, an aortopulmonary shunt. And then at 15, developed marked limitations in activity. A catheterization showed severe RV efflutract obstruction. Complete occlusion of the BT shunt and near occlusion of the AP shunt. And at age 15, underwent complete Tet repair. VSD closure, large patch over the RV efflutract. The most recent echocardiogram had mild TR. Right atrial area of 29 centimeters squared. Left atrial area of about 30. RVF quite diminished at 30%. And LVF at 54%. Right ventricular pressure, let's just say about third systemic. A TAPC of about 16. No significant RV efflutract. Moderate pulmonary regurgitation. And this is the atrial tachycardia with the right bundle branch block. And maybe again a little bit of left axis deviation consistent with the day already. I'm going to keep that in mind, but I also want to throw this out there. What if this was also seen on the halter nine months previously? Not the same patient, just some runs of non-sustained tachycardia that I just threw in there. So how do you approach flutter in these TET patients? Medical management, catheter ablation, anything to do aside from a CTI flutter ablation, especially if you can't start it back in the lab if you're not going in the flutter. What if you have brief runs of atrial fibrillation and post-ablation evaluation, other studies? So let's sort of take a discussion about atrial flutter, maybe some atrial fibrillation in our TET patients. And with that, I'm going to stop sharing and have our wonderful colleague, Dr. Natasha de Groot from the Netherlands comment. Thank you. Yeah, well, we'll start with acute management when a patient presents with regular tachycardia at URR. What we usually do with the congenitals is we don't give antiarrhythmic drugs. We usually go immediately for electrical cardioversion. So I'd like to hear from my colleagues what they think about that. And if it comes to the long term management of these arrhythmias, we're actually quite aggressive. We always go for an ablation procedure. In this case, you have both atrial fibrillation and regular tachyarrhythmia and like in a patient without congenital heart disease it's nowadays combined if they have both you do both pulmonary vein isolation and a flutter, cavotracuspid isthmus ablation. For the congenital in this case we know that the phallus often have the intraatrial antithagycardia and cavotracuspid isthmus dependent atrial flutter. If you have only a short run like on this halter you could also say yeah perhaps that's how the atrial flutter initiated it because flutter usually starts as atrial fibrillation and then it stabilizes so I would like to have a little bit of a longer period before I would do something and then comes the question if you go to the cath lab would you also combine it with a pulmonary vein isolation and I would not do that I would really go for the flutter ablate the flutter and then wait what happens but yeah I would like to hear what my colleagues should do in this case. So Anne why don't you get started? No I would 100 I was at first I thought Natasha was going to say that she would do both in the same sitting and I'm like oh my that would be quite the day in the lab. No I 100% agree I think that with that short a burst of AFib I would be tempted to try and get the other atrial arrhythmias under control and see if the AFib then you know kind of disappears at least it's not going to be gone forever I mean there at some point this patient is going to be making it back to the lab for an AFib ablation but you know the longer that you can go without if he's doing fine and has no other arrhythmias the better. So we would probably plan on attacking you know doing a flutter an isthmus line as well as looking for other interatrial sites looking for other atrial tacks and and attack it that way. We also I think it's changed a lot over the last you know 5-10 years it used to be we were much less likely to get to the lab early it used to be that we would treat much more and I'm curious if you remember this as well we would treat more with anti-arrhythmics for longer periods of time before we would actually bite the bullet and go on in and do an ablation. I think nowadays we're much more likely to you know maybe allow somebody to have one episode but that might be the end of it and then we we say we we at least offer it after that first episode and if there's if they decide against it and want interarrhythmics we place them on it and then by the second one we really try hard to. I would say I would agree with that I think there's a definite shift that you know I think even 20 years ago 15-20 years ago would be global cardiovertum and then we'll schedule a flutter but I think now you just you get into the lab and you're going to map the circuit. So let me Jeremy let me ask you suppose you um anesthesia gives some magic medicine and the flutter breaks um and then you can't induce anything you know you're you're pacing you get all you induce is non-sustained garbage afib that self-resolves um what are you going to do in that situation? I think I know what I might do but I'm curious what you might do. Well I I don't usually run into that situation I'll just be perfectly honest with you I do a lot of burst pacing when I induce I don't I do extra stimuli but I go straight to burst pacing and I find all kinds of things um and I very rarely do I not induce multiple actually arrhythmias so uh but yeah I think if I for some reason couldn't induce something I would obviously take out the CTI do a substrate map look if there's an atriotomy you know interrupt that isthmus um you know I don't normally for atrial arrhythmias at least I don't normally look at the conduction properties or velocities um if it's a narrow short isthmus I'm going to probably ablate it as long as it's safe um but yeah I would do substrate-based ablation in that situation. So let's say you do that let's let's I mean I think that's that's the norm I think we can start the CTI flutter pretty easily I don't think that tends to be the challenge I think it's we tend to start a lot of other non-sustained atrial stuff or where the the PP varies a lot it's not a consistent you know you you how much do you keep pushing it once you get to that line yeah so if it's sustained and if it's regular I'll go after it if it's irregular non-sustained I will try several times but if I can't get it to persist long enough to do an actual map I'm not gonna start you know doing crazy things but if I can get it to sustain and if it's mappable in terms of being regular then I'll then I'll go after it and sometimes you find multiple flutters yeah yeah and what is the group do I'm curious what people do uh anti-arrhythmic therapy after this ablation whether you had some non-sustained AFib didn't have some non do you do you watch them off anti-arrhythmics do you um leave them on something for a couple of months much like the adults might do with AFib or you sort of just go around the room with that question so like I personally I just if they were on beta blocker before the procedure I'll leave them on beta blocker if they were on nothing I'll usually just I don't start anything that's my personal approach and Natasha um yeah we put them an anti-arrhythmic drug and we we leave it for like three months and then we do halter monitoring and if the halter monic does not show any arrhythmias we discuss it with the patient whether we can reduce the anti-arrhythmic drugs and try to stop it unless we see of course episodes of AFib and then which is actually usually case if you still see some runs and you leave the patient on the anti-arrhythmic drugs yeah I'd say we we pretty much put it on beta blockers are good things um and so we tend to put people on on beta blockers following um and I think how long we treat them for and and how aggressive we are with it really depends on how comfortable we are that we've gotten everything at the time you know there are times that you go in and you feel like you probably gotten most of it you think it's probably good enough you don't want to keep pushing um but there may be something else left in which case then we tend to go ahead and um we'll we'll keep them on it for longer periods of time but usually three to six months at least so Mitch I'd like to retract my statement based on that yeah so if if there if it's not a completely successful procedure then I think it's reason I would put them on beta blocker but if I'm complete if I bladed multiple flutters are completely non-inducible and I don't always put them on something yeah no I think that that's that makes perfect sense good does anybody have any other comments about atrial arrhythmias in in this population no a lot of them the only thing I would say is this patient I think was 49 right and and it seems like around 50 is where you start to see that change from atrial flutter to atrial fibrillation so I think this patient's going to be back with atrial fibrillation and um probably just a matter of time and once we start having better tools for atrial fibrillation ablation like pfa and those other things that are coming I think it's it may be the the threshold to do uh pvi at the same case may go down but we'll have to see how it goes all right let's move on to the third case so this is a 37 year old tat patient presents with palpitations and near syncope she had similar episodes six years ago and actually fainted though she attributed to being dehydrated as a typical 100 degree weather on the east coast as it is now had an initial bt shun at two months of age at three underwent complete repair of tetralogy no operative report is available which is not that uncommon sometimes uh did well through adolescence one healthy pregnancy she exercises about three times a week and was lost to follow-up during college but considers herself to be near class one uh six months ago she had an echocardiogram that showed mild tr moderate severe pulmonary regurgitation an rv ejection fraction 50 percent and lv ejection fraction 58 percent and rv pressure one-third systemic uh she has uh in sinus rhythm baseline qrs of 160 and right bundle branch block from an ekg six months ago and she now presents with this and i'll just leave that up there for my colleagues to look at but obviously for everybody else uh to look at um and then we can comment it when we get to the discussion um so your approach to stable slow vt medical management catheter ablation what if you get to the lab you can't reinduce it do you absolutely do an mri before the ablation what are you looking for consideration for icd yes no sort of an approach really to this particular patient um with that i'll stop sharing and i'm going to let dr jeremy more sort of take the lead on this case so yeah i think i don't know if you want to put the ekg of the vt up actually but um the um it sounds like this patient doesn't have a lot of classic risk factors for vt which i think is also something to think about here you got good ventricular function not late agent repair uh the qs is not that wide it's 160 milliseconds um so i think this is kind of illustrates the fact that you can i mean if presuming this is a real case that you can have vt within the absence of risk factors um which you know i think you know makes us a little more wary about sending patients for valves without ep studies um but um in this particular case does have a left bundle pattern of vt um and i think it's um i remember correctly as an inferior axis but what we would do is take this patient to the lab um everything else looks pretty reassuring so i think we would try to induce the v we'd start with a three-dimensional map of the of the rv we'd look for slowly conducting anatomical isthmuses and then we would try and induce the vt um you know i think ways to um localize the vt are going to be based on the morphology so we'd be focusing on exit sites in the rv free wall with this left bundle morphology if we were able to induce the vt we would pace map at the areas that looked concerning for conduction isthmuses uh if we're we have a stable vt we could even try and do activation mapping of the vt itself and then um do some entrainment maneuvers as well so i think this is the kind of case where you'd want to try and ablate the vt be really sure you know where it's coming from ablate it show that you do have bidirectional block across that isthmus after you've ablated it and if everything looks really good and you have a patient who's otherwise low risk with good ventricular function and came in with a stable vt i think that could be definitive therapy here yeah i i sort of would agree with that um and why don't you go and then we'll let natasha sort of close out this case yeah i mean i was only i was about to ask um what kind of energy would you all use in this scenario i think we would we have really shifted over much more especially with ventric vts to irrigated tips um and to really make sure that we have a deep enough lesion um and are um having a true change here um i think that's pretty common across the country and even internationally now i know there has been some discussion of pfa also in this scenario um some very early work here as well um so i think that's also an important thing to to mention that i believe that's probably coming um i tend to um i agree in principle with jeremy as far as if you're really convinced you got it that may be all you have to do i at least put people on beta blockers even if i'm pretty convinced that we got it just because um and that's not a really good reason i know but with vts i do it um and i i tend to really want to be convinced that i've gotten rid of this before i'm just comfortable saying that's all we're going to do and not think about a device in this scenario yeah natasha um yeah our approach is that we induce the vt uh we from activation mapping and train that mapping preferably though we do have the experience that they should perform and train the mapping it certainly transitions to another vt um so that's actually our approach um and i wondered actually if you induce another vt which is not clinically documented would you go for it because you know that if you have a stable vt and it's not the same you ablated already the clinical vt what are you going to do and my second question to you guys was do you use specific induction protocols after you terminated the clinical vt and how aggressive are you going to be can i yeah jeremy why don't you you take the lead and then i'll chime in i've got one other question specifically for you also so the the first one i think was if you induce another vt what do you do in my mind if you're not going to put an icd and you've got to get rid of all the vts i think because if you have an inducible vt at the end of the case then i wouldn't feel comfortable this patient's low risk anymore so personally i would go after it if if there is a sometimes you just see it going in the opposite direction you know sometimes it's just a different morphology and it's the same circuit but um yeah if there's a different vt i'd absolutely want to get rid of that and um the second question was how do we induce uh our protocol is triple extra stimuli two sites down to 180 milliseconds which is usually pretty aggressive in terms of sometimes we even see polymorphic vt and some other things that are related to the short coupling interval probably um but we we want to make sure we get everything that way so we'll do we'll go down to 180 and we do two sites and baseline in with isopaternal yeah i think we would approach it the same way down to 180 i probably wouldn't get to more than triples i know there's people have talked about getting to more than triples but that seems to be getting a little more non-specific jeremy let me ask you what about uh you sort of alluded to this in your talk also and talked about it but i think people might not know about like really the reference of the right coronary cusp to the rv outflow tract um for this in an area that really should not be ignored when you're kind of getting up in this area so if you want to just touch on that as well yeah just just the anatomy of tetralogy flow is kind of fascinating how the aorta kind of sits in that area where the uh the vsd obviously is and the pulmonary annulus and you have that all of those structures are all related to each other so um you can have cases where and i think it was a leiden group that really pointed this out back last almost a decade ago now but uh you can have left-sided circuits in terms of either in the coronary cusp or even sometimes in the lv but most usually the coronary cusp is this is the place to uh to target if you can't get there from the rv endocardium so yeah going retrograde uh into the aorta uh looking at the vt looking for fractionated signals in that area uh sometimes is the way to go and you can ablate there you got to think about the coronaries obviously and the valve and everything else but um you can ablate those vts sometimes from that side should not be forgotten yep good uh anybody else any other comments i think we've the talks have been fantastic i think this panel discussion was great and um and natasha jeremy thank you so much for doing this

Tetralogy of Flow

ablation

atrial arrhythmias

ventricular tachycardia

conduction system pacing

risk stratification

post-procedure care