It's my pleasure to present our first speaker, Dr. Ulrich Krauss, who will talk to us about early experience in pulse field ablation in congenital heart disease. All right, let's see. Okay, so let's see if this works. All right, here we go. All right, good afternoon, ladies and gentlemen. I would like to thank the organizers for inviting me to give a talk on early experience with PFA in CHD. I will present you some data on off-label use on medical devices, so that's to make that clear. And what is PFA, pulse field ablation, is a novel non-thermal technology, which has been CE marked for catheter ablation of atrial fibrillation in 2021. And it works by application of an electrical field at the membrane of cardiomyocytes that causes irreversible formation of nanopores within the lipid bilayer of the cell membranes and ultimately results in cell death. Because the strength of the respective electrical field is tissue-specific, PFA is considered to be safer with respect to collateral damage compared to thermal catheter ablation with either cryo-energy or radiofrequency energy. It has been developed since 2012. So on the bottom of the slide, you can see how PFA was developed. It has been developed since 2012 with the first human use, abicardially in 2017 and endocardially one year later. And in 2021, the Boston Scientific PFA system was CE marked for catheter ablation of paroxysmal atrial fibrillation, specifically for pulmonary vein isolation of paroxysmal atrial fibrillation. Now, nowadays, there are a couple of companies offering catheters and PFA ablation systems. And this is just to give you an idea of what is available on the market. So we have the Boston Scientific system. Okay, that's a little slow, the arrow. All right, on the top, you'll see the Boston Scientific FARA Pulse System. This is the first PFA system which became CE marked and also FDA approved. Then they have the Medtronic Pulse Select and Medtronic AFERA system. The Medtronic Pulse Select is a helical catheter, and the AFERA is like a small cage or small sphere, which can be used for catheter ablation, either with pulse field ablation or with radiofrequency ablation. And Abbott will launch its Volt catheter, which is quite similar to a cryo-balloon. And there's also, and this is something different, there's also the CardiFocus Centauri system, which you may know. This is just a PFA generator, and you can hook up commercially available radiofrequency ablation catheter, for instance, a Navistar or a TactiCut catheter, and use this RFA catheter with pulse field ablation for focal pulse field ablation or for induction of ablation lines. Now why are we interested in using new ablation technology for catheter ablation in patients with congenital heart disease? Well, one thing is that the incidence of atrial fibrillation is increasing with the age of our patients. As you can see on this slide, so the gray columns represent the incidence or the prevalence of atrial fibrillation in the congenital heart disease population. And above the age of 50, the prevalence of atrial fibrillation becomes higher than the prevalence of intraatrial reentrant tachycardia. And the other thing is that while at younger age in the congenital heart disease population, as we know, CHD complexity, the presence of bradyarrhythmias, but also the number of cardiac surgeries are the major risk factors for development of intraatrial reentrant tachycardias or atrial fibrillation. And with increasing age, also the typical risk factors from the non-CHD population become prevalent in the CHD population and require catheter ablation of other substrates than just the typical CHD substrates. Now, so this is one reason to also deploy new technologies for catheter ablation in the CHD population. And how good are we with currently or with so far used technologies, the term ablation using cryoenergy and the radiofrequency energy? This is a study from our group, which we published a couple of years ago. If you look on the recurrence rate, I mean, the recurrence rate in our population is up to 50% after a follow-up of five years. So there's a considerable amount of patients who has ablation of atrial tachycardias, intraatrial reentrant tachycardias, who have recurrence of either atrial tachycardia or atrial fibrillation on the long-term cause. The reasons for that are, on the left side, you can see the endocardial map of a patient with Tetralogy of Fallot recurrent IIT after repeated radiofrequency ablation within the right atrium. This is a horrible voltage map of this right atrium. Almost the entire right atrium is electrically altered, and there's a lot of substrate. You can imagine how hard it is to target this substrate with a focal catheter, like a radiofrequency catheter or a focal cryoablation catheter. On the right side, you see the map of an atriopulmonary anastomosis Fontaine patient, who originally had tricuspid atresia. And this was a patient who was admitted for several times to ablate this intraatrial reentrant tachycardia within the systemic venous atrium, and it was impossible with radiofrequency ablation to treat this tachycardia on the long-term cause. We always had recurrences. And then those two patients, because radiofrequency ablation was inefficient, we decided to ablate those patients with PFA, and those are the results. On the left side, we almost completely ablated the anterior right atrial wall, and this patient didn't have recurrence of atrial tachycardia since then. And on the right side, you can see we could induce a lesion line using a PFA catheter. So we used the Boston Scientific System thyropulse catheter in its flower configuration, and we were also able to induce a conduction block in this patient by deploying pulse-field ablation. Now, what do we know? So if we look for what has been published on PFA and search for pulse-field ablation atrial fibrillation, we get a bunch of results, especially during the last two years. But if we search for pulse-field ablation in congenital heart disease, we just get 18 results. And if we go through those articles, there are not 18 articles on pulse-field ablation in congenital heart disease, but it's just three articles or four articles on the use of pulse-field ablation in children or patients with congenital heart disease. So this is one of the first studies that has been published, and this is actually not on congenital heart disease, but it's on ablation of accessory pathways, and it's a study from Croatia. And they enrolled three adolescents between 30 and 17 years of age, and they used the Centauri system to ablate, what you can see here, the accessory pathway by deploying pulse-field ablation. And if we go specifically to patients with congenital heart disease, there are just two publications so far. This is one case report from our institution, a 33-year-old male patient with Epstein's anomaly after ASD closure and Glenn procedure after WPW ablation, deploying radiofrequency ablation with recurrent VT. And we tried to ablate the VT using radiofrequency ablation, but it recurred. And this patient had a defibrillator implanted, had discharges of his defibrillator. And so we decided to ablate or to target this VT deploying pulse-field ablation, and this is the map of the VT. You can see the atrialized right ventricle on the left side, on the right side, the right ventricle. And this is the map of the tachycardia. And we used, again, we used the thoropulse system in its flower configuration to ablate this VT. And since then, we did this procedure in the end of 2022. Since then, he didn't have recurrence of the VT, so it was quite effective. Now, what has been published on the ablation of atrial fibrillation, atrial tachycardia in the CHD population using pulse-field ablation, there's also only one report on that so far. It's also from our institution. So this is what we published one year ago. We had 21 patients. Mean median age was 58 years. Most of the patients had atrial fibrillation. Only a minor proportion had atrial tachycardia. We had a procedural success of 100%, which means that we either terminated the tachycardia or were able to prove conduction block. We had quite short follow-up of six months in median, no AF recurrence. And that's it, what has been published so far. But we have more data since publication of our, and I would like to share this data with you. With March 2022, we had 48 patients. Of those, half of the patients were female. Age didn't change. Median age was 57 years. Follow-up now is 13.5 months. And we used for mapping the N-SideX system, and we still exclusively use the Farapel system. This is the distribution of congenital heart disease complexity among the patients. Most of the patients, almost half of the patients, had CHD with moderate complexity, but there's a considerable amount with also severe complexity. And like 73% of the patients had either lone atrial fibrillation or atrial tachycardia plus atrial fibrillation, and approximately 30% had only atrial tachycardia. Of those patients with atrial fibrillation, 58% of the patients had paroxysmal atrial fibrillation, and 42% had persistent atrial fibrillation. Now most of the patients also had previous ablation, either deploying radiofrequency alone or cryo-energy plus radiofrequency. And just to clarify, it was not focal cryoablation what was used in these patients, but it was pulmonary vein isolation deploying the Medtronic cryo-balloon. Now procedure duration, those are long procedures mainly due to a long mapping time of 148 minutes in median. Fluoroscopy time is considerable because the Farapel's catheter has to be moved by fluoroscopy mainly. Additionally, radiofrequency ablation within the right atrium, mainly within the carpal tricuspid isthmus, was deployed in 20% of the patients. And in one patient, in a Fontaine patient with a focal atrial tachycardia close to the sinus node, we used additional focal cryoablation. PFA target, so the target substrate was mainly in the right atrium, 33 patients in the left atrium and in the right atrium in another six patients. And in nine patients, we exclusively used pulse field ablation within the right atrium. A median number of PFA applications was 48.5, and there was no statistical difference in the number of applications between ablation within the LA, the RA, or in both atria. And now if we go to the procedural success was 100% again, so we were able to reach our procedural endpoint in all patients. And the recurrence rate over the follow-up of almost 14 months is, I would say, quite low. It's just 15%. We had two patients with recurrence of atrial fibrillation, and the other patients, we had recurrence of atrial tachycardia. So this is, I think, what also has been found in the PFA registry, which is led by the Boston Group here in the US. Complications. We had one complication, which was specifically attributable to PFA itself, but we had to – sorry, we had one complication, which was specifically attributable to PFA. This was a coronary artery spasm. After ablation within the carotid cuspid isthmus, we had one pericardial effusion, which you can see on the right side in a lady with a large ASD device after a transheptal puncture. On the bottom, you can see the pericardial tamponade, and we had to put in a drainage. And we had one inguinal hematoma. Now I would like to summarize and conclude. So I think with respect to efficacy and also safety, if we look only at PFA itself, PFA, it's effective and safe for ablation of atrial fibrillation, atrial tachycardia in our patients. The midterm outcome is favorable. Long-term results are pending. Also, multi-center data is still pending in comparison to other energy sources like cryo-energy, like RF energy is pending. And I mean, you have to keep in mind that if you're ablating close to the coronary arteries, ablation is possible, but you can treat it with application of either systemical or intracoronary nitrous. So thank you for your attention. I think the paper is open for discussion, and if you want to contact me, this is my email. Thank you very much. Thank you very much, Dr. Krash. Clearly this technology is here to stay, and it's really wonderful to hear from the people who had the most experience with it in our field. So thank you for sharing that experience. If there are any questions, please do come up to the microphone. Yes, George. Hi. Nice summary of your experience. Can you say a little bit about how you think about hemolysis in this patient population? So it's one of the issues that happens in every single PFA is some level of hemolysis. Are there patients in the congenital heart disease population that you think are probably not candidates for this because of that particular problem? And how do you approach, you know, do you look for hemolysis, do you look for renal function? Yeah, this is a good question. Thank you for that. So we had one patient who had some hemoglobinuria the day after. This was the one patient with a very high number of PFA applications. So there was one patient here with, oh, sorry. You can see the slides again. Okay. We had one patient with... Oh, you can now. You can now. All right. Sorry. Yeah. So this is on the left side. Within the LA, we had one patient with 99 applications, and he had some hemoglobinuria the day, but we didn't have kidney problems. And we checked after 24 hours, and the hemoglobinuria was completely absent. We didn't have kidney problems. We didn't have problems with the drop of hemoglobin count. And so my personal approach is to check for hemoglobinuria if we do more than 50 applications. If we do less than 50 applications, I don't check. We didn't have problems with that, so... You show a picture with an entire right atrium was kind of like ablated. I mean, are we essentially creating atrial stents still for those patients? Yeah. So the question is, what do we do with anticoagulation? During the procedure, we, of course, use heparin with a target ACT of 300 to 400, like recommended by the manufacturer. And after the procedure, if we do gross ablation within either the LA or the RA, of course, there's a probably significant risk of thromboembolism within the atria. And so we put them on direct oral anticoagulation for at least three months. But in those patients with gross ablation, I put them usually, if they have a CHA2DS2-VASc score, I put them on anticoagulation forever. Yeah. Well, given the fact that you only had the theropulse catheter, but let's speculate, you would have, let's say, centaui. What would be your choice? Because when I'm seeing kind of a big footprint catheter, would you rather use a small catheter, or is it just a matter of availability? And what would be your benefit? It makes massive lesions, of course, but tell us a little bit of what you're talking about. So, I mean, if I have a right atrium like... Just a second. Where is it? So, if I have a right atrium like that, I think I wouldn't have much benefit from a focal catheter. I would use the theropulse in its flower configuration to get rid of this large area of substrate. But if I would have a focal catheter to ablate the substrate in the Fontan patient on the right side, I mean, I think it's just to have a good line here. Can you see that? No, you can't see it. Okay. So, if I have a circumscribed substrate, I would use a focal catheter and not the thyropulse catheter. But if I have a substrate which is distributed over a large area, I would use the thyropulse or a similar catheter. Because this is one of the advantages of those catheters, that we can cover a large area. I think that one of maybe my last comment, and then we move on. I think the concern was also the kind of transport function afterwards, right? And there are some patients, as you pointed out, the Fontan patient probably needs more, rather less stunning and less non-contraction. Maybe that's part of the equation we need to learn on which is the best tool to apply. That's what we have to study. I mean, what we study now is the effect of pulse field ablation on the arrhythmia and on the myocardium. But we also have to study what is the effect of such large ablation on congestive heart failure, on well-being of the patients, on quality of life, all of that. Fantastic. I fear we have to move on to the next speaker. Thank you. Thank you. And the next speaker is Daniel Vartus. He's going to tell us about leadless pacing and experience in general heart disease. So I think we narrowed it down a little bit. Oh, sure. Thank you. We have to close that. Yeah, that's good. All right. All right. I guess we're good. We'll get rolling here. My name's Dan Cortez. I'm over at UC Davis Medical Center. I'm pediatric and adult congenital cardiologist, and like many of you, do electrophysiology. So we're going to talk just a little bit about early experience in atrial and dual chamberlain pacemaker implants in adults with congenital heart disease. Clearly, there's no large database of these. This is very early. And instead of just choosing sort of some typical cases, I'm going to go ahead and present some, I guess, less than typical cases. By the end of this, you'll have some ways of assessing ACHD patients preoperatively for leadless implants. And feel free to, I know we're all thinking about this. So if you have questions at the end, please let me know. And you should have some better idea of sort of the use of leadless pacing in ACHD. You'll have an idea of alternative access approaches to dual chamber implants. And then also learn about various anatomic considerations, which you can just keep in mind when performing in complex anatomies. So we'll go through a few cases. Then we'll talk about kind of what else is out there in the literature and go with that. So the first case, we'll just talk about a dual chamber implant from an alternative access site. Case B, we'll talk about a dual chamber implant with two different ventricular devices. And then case C, we'll talk about atrial pacing in a patient with a Fontan. So of course, we have this one year safety data from dual chamber leadless pacemaker from the aviators. And that's out. It's pretty decent with, of course, we've got to keep in mind some things about battery longevity, discrepancy in battery longevity, things like that. But I mean, overall, primary performance about 90, almost 93%, complication free about 89% of the time. There's really one case report on a dual chamber leadless in a patient with congenital heart disease out there that we put out there a while back. And then there's some other sort of trickling down. So again, it's basically case-based. So there's not a ton of data. So we'll have to get more. But let's talk about a dual chamber implant. So we had an 18-year-old active basketball player, a male with history of large perimenopausal VSD closure in a heart block. Had epicardial lead placement. Had these unipolar 4965 leads at six months of age. Underwent device and lead replacement at age seven. Discussed having difficulty with lead placement. But did it. He also basically presented with ventricular lead thresholds that were very variable and with high impedance episodes. And again, the replacement leads were also unipolar, unfortunately. So just not a lot of options. Also, he wanted to keep playing basketball, be very active. And he presented for pacemaker revision. Also had bilateral femoral vein stenosis. And really, for this patient, we had talked about a few options. But when you look at his echo, one thing we measure when thinking about if a patient's interested in leadless and if we think that may be the right choice, one thing I like to do is I actually like to go from the apical forward chamber view. I like to look at the distance from where the atrial appendage may be to the tricuspid valve to make sure that distance is sufficient for whatever leadless I'm going to put there. And then also, I go from the apical septum of the RV out to at least 38 millimeters to make sure I'm not going to inhibit the tricuspid valve closure. So again, just thinking about how do we preoperatively plan this a little bit. So this is my favorite view to think about these patients. And it's nice if we open the atrial appendage a little more. So he also really wanted to do some other sports and collude. And we've had experience with patients actually with ventricular leadless and with atrial doing things like tackle football, wrestling, things like that without any issues, clearly graduating them slowly into that. And so he is actually very interested in some contact sports as well. But long and short, we ended up doing leadless. Given the ephemeral vein stenosis, we ended up doing from above. The left IJ and the right IJ are both nice access sites. In smaller patients or patients with sort of ephemeral vein stenosis, et cetera, whatever it may be, they're on dialysis. They really have issues from below. IJ is kind of nice. I actually kind of prefer the left IJ for a ventricular lead implant. I usually just choose whatever vein is the biggest, because I know I'll have the less mark. And then thus far in follow-up, we always assess these veins six months later and haven't had any narrowing of the veins with Valsalva. So again, just kind of showing from an RAO and LAO perspective, I have TEE here. I do like to use TEE in patients with general heart disease or smaller patients, especially for the atrial leadless implant. I don't think TEE is necessarily for ventricular, but we'll get to the atrial component. So the reason I like it for this aspect is that we can really see the atrial appendage, see exactly where we are, make sure we're not too deep, and again, just kind of reassuring. So basically, in order to implant an atrium, so the ventricular is pretty straightforward, right? You go in, you're kind of there from left to right IJ. Key is you've got to get your sheath back far enough when you implant to make sure that when you push, you're not curving up too much. But for atrial, really what I do is I go in first with a device. I give a little extra space, make sure the device isn't pushing on anything, and then either an IBC is preferred, or you can go across the tricuspid valve and basically create that bend. Then you come up, kind of like you're using a J stylet, come up to the appendage. And then once you're there, you can see the catheter can bend like this very safely in this LAO position. You then eventually have to sort of take off that bend in order to actually torque it in. So there, it's a little bit of adjustment of the sheath, but make sure you have a nice enough curve that you can torque in safely. Implant characteristics, this patient had basically atrial threshold of 0.5, 0.4. 0.5 volts at 0.4 milliseconds. Impedance was 340. With that inner helix, you always get a little, for the aviar ARs, you always get a little bit of a lower impedance. And then P wave was 1.6 millivolts, and then 1.8. The ventricular threshold was also a good 0.5 volts, 0.4. And then higher impedance, of course, were in the apical septum. And then a good R wave. The next day, they couldn't find an R wave when they lowered him to 50. He was pacing just all the time. Set him 60 to 180. Nice thing is, for these younger patients or really athletic patients, you can get that tracking rate up pretty high. So 180 is pretty good, as opposed to maybe other acceleration-based devices. And then use a 30-centimeter introducer from above, of course. Eye-to-eye was about four or so for A to B and B to A. And follow-up, similar sort of stable thresholds. P wave came up nicely, 2.8. But I really like to program these devices at 0.2 milliseconds, just to really try to push that battery longevity. Ended up, and then the eye-to-eye was getting better. And as we typically find with these dual-chamberley lists, the eye-to-eye gets better over time in most patients. Longevity about 6.9 for the AR and the VR of 11. Some a little bit later was able to get that longevity up. But I still kind of maintain, as I get them active, I still maintain a little more than just a 0.5 volt sort of space there, buffer, as I allow them to gradually get more active. Let's talk about case B. So this was an infected device, an alternative sheath approach. This actually was a patient who, 27-year-old gentleman, had dextrocardia, double-outlet right ventricle with a subaortic VSD and pulmonary stenosis. So basically like a Tetralogy of Fallot kind of physiology. And had multiple pulmonary valve replacements after his initial repair, and had had endocarditis, as well as multiple infected sternotomies, and also his liver failure stage for cirrhosis. Basically had had his, yeah, basically just wasn't doing great. Had had a bunch of sternotomies. Surgeon really didn't want to do any more, but had also had syncope at history of syncope and ICD placed 15 years prior for syncope they couldn't explain, but then on his ICD the only thing they ever found was that he had rapidly conducted flutter, which he got an inappropriate shock for once, or I guess appropriate because it was flutter I suppose, but it wasn't VT, and never saw VT, and had an ablation of atriotomy-based flutter seven years prior to meeting him, and developed sinus node dysfunction after that. So atrial pacing was 100%, ventricular pacing was about 17%, and again no appropriate shocks. LVEF was stable, 50, and again just, and had presented to me after he had had a generator change out, and had MRSA and a grippy strep. So basically lead extraction was indicated at that point. So ended up doing a lead extraction. Unfortunately he was in the area where they had dual coil, where we were doing a little more dual coil ICDs, so he was a right-sided dual coil ICD, you know, a dual core ICD. Extracted it, and then given that he really just needed pacing at that time, and really hadn't had any documented arrhythmias, and his EF was stable, you know, LVEF was 50%, really, and for minimal risk of infection, and also because the left side was also deemed, they had some issue with the subcleaving vein on the left as well. That was, his subcleaving vein, he had some stenosis, and had a bunch of PICC lines on that side. So basically we ended up opting to head to leadless for less surface area footprint, and then also just because really he needed pacing. So at that point actually, this was right after the AR had been, well, I think it was right before, like a week before it was approved, but we couldn't get it at our hospital. So we ended up doing dual chamber a slightly different way. And so ended up effectively doing a micro AV2. This had actually just been FDA approved as well, and got that for compassionate use, a micro AV2 in the ventricle. And actually through the same sheath, the aviar sheath, because the inner diameter is about 25 French, you can actually, you can put the micro, you can put the micro catheter or the aviar catheter. So we just use the same catheter. This is him days later after having temporary atrial pacing. And then we ended up putting a aviar VR in the atrium actually, because we knew that that would have the better longevity, sort of higher, you know, more milliampere battery. And so we ended up putting the aviar VR in the atrium there, and then AV, micro AV2, and then took out that temporary wire. So you can just kind of see that's how they're hanging out together. We'll come back to him. Follow-up was great. He had nice thresholds, all sub one, only be paced when he winky boxed, which was over sort of 90 beats per minute or so. And then the AR, with a VR, with a threshold of 0.5 at 0.2, his, with an output of one volt at 0.2, his, and impedance in the 600s, his predicted longevity is around 18, 19 years or so from implant. And with a micro AV2, it's still over 10 years, because again, he's only pacing about, be pacing about 10% of the time. KC, Fontan patient. So we had a 30 year old male with complex history, tricuspid atresia, Glenn procedure, Fontan surgery. He basically had presented to outside institution with a persistent atrial flutter, initially managed with rate control using diltiazem. And the thought was he was in chronic AFib as well, so they just wanted to rate control him. Unfortunately, with all of that, developed hypoxic respiratory failure, congestive heart failure, reduced EF down to 38%. He did have a dual chamber, had had a couple of dual chamber pacemakers placed as well. And at that point, you know, again, their plan was, you know, potentially AFib, you know, keep him in AFib and do an AV nodal ablation and goal-directed medical therapy. Due to ineffective rhythm, we said, hey, maybe let's bring him to the EP lab and let's see what we can find, because his, this is really his EKG. There's his, there's his diagram. And then really he was, the only thing we ever really saw was flutter. So we thought, you know, we can take care of that flutter and let's see how he's doing after that. So we did that. This is just a nice CT of him. He reported significant symptom relief, reduced ventricular pacing burden. So basically his device, the atrial lead was broken. His ventricular lead, you know, his fractured to super high impedance wouldn't capture. Ventricular lead would capture only unipolar at max output. And so we dialed him down to just a backup rate about VBI 40 just to make sure he didn't have syncope and sort of wanted to see what his heart rate did. He, you know, felt a lot better. He, this was about a year and a half before we did anything else. He still had exertional dyspnea. He was trying to play with his kids, do more than just walking around the house. His Holter demonstrated heart rates 48 to 99. Average heart rate was 61 and, you know, no real significant RRR pause, no further arrhythmias. About a year and a half later, still with multiple monitors, really didn't have any further flutter. So took him for a combined sort of temporary patient study and cath. During the cath, ended up basically finding that, and socially it took him a little while to get his, get him to the cath, but basically found he had higher Fontan pressures with his lateral tunnel Fontan. He also, with pacing, those reduced quite a bit. So ended up, and we'll talk about that a little more specifically, ended up basically, given the temporary pacing seemed to help him quite a bit, temporary atrial pacing, and he did in WinkieBlock up to 180, ended up placing, actually, AVR-VR. So this is, sorry, more of an AP view, just showing sort of injection contrast just to try to show, kind of, this is an LAO, just to show it was more sort of septal. He had had a fenestration that had been plugged, and so, anyway, after release, sort of looked like this from the RAO and LAO. His, of significance, his, with atrial pacing only, his Fontan pressure decreased from about 24 to 20. His cardiac output also increased by somewhere around 23%, which, again, isn't unheard of, going from a heart rate of 50 to, you know, to a lower rate of 80. So ended up, so we placed that. His implant was about one volt at 0.4 milliseconds, impedance was 820 ohms. R-wave, we couldn't really see what the injury pattern on there, or the P-wave, really, and we basically set him VBIR 80 to 130 with a just really low rate response, just wanted to see, kind of, how he felt first before we dialed up the rate response aggressively. Follow-up six weeks, he was atrially paced about 94% of the time. The threshold was 0.5 at 0.2 milliseconds, again, impedance at 690, R-wave 2.5 millivolts, and final device settings were really rate response around two to seven. Predictive longevity of somewhere around 18 years or so when we lowered him down to one volt at 0.2 milliseconds. We had done, you know, we have a protocol for these patients, basically. Monthly ECHOs, putting him on anticoagulation for six months as well, just to make sure that we're not, you know, clearly there's a clot risk, especially in that initial time period, and then we started Tadalafil, of course, given his Fontan pressures, and then planned for a repeat cath in a year. Most importantly, he's now able to play with his kids. He walks them to the park. He does so without shortness of breath, can walk three flights of stairs now. He really did not want an epicardial, another, you know, another, you know, epicardial device or surgery, and also on the last implant note, they also had described how difficult it was, and he remembers being in the hospital for a week and a half afterwards. From the last one, so this was kind of a nice option, just give him a little atrial pacing. And this, it just sort of shows his lateral tonal Fontan here, and then shows, oh, I apologize. We're moving on to this one. So anyway, next one, we'll just talk about, now let's talk about like some of the other cases out there. So this was, we had a patient who we were in the middle of, we did a combined, oh, two minutes, thank you. So a few other cases that have been around. This is just one patient who basically has, he's not quite a hemifontan, but basically atrial appendage to, right, pulmonary artery, and SVC to right pulmonary artery connection with the RV to LPA connection, who had a ton of flutter and a lot of sinus pauses afterwards, after ablation, so ended up doing a AV or VR on him. This is an interesting case from East Coast, I think it's from Atlanta, I want to say, and they basically were, they had a patient who failed lead extraction for ICD leads, but really needed atrial pacing, went into heart failure for months in between as they were trying to figure it out, diuresim, et cetera, see if he really needs atrial pacing, and they ended up placing AV or AR in his left atrial appendage. He, this patient, with the initial placement, it failed within, I think, three weeks, they had to replace it, but on the replacement, that's working well, and they had a nice implant threshold and long-term follow-up. Only other thing they did, there is a second dual-chamber leadless pacemaker case that's reported out there as well in a patient with prior leads who has a glen, and that's sort of out there. So again, not a lot of stuff out there, but long and short, atrial and dual-chamber leadless is available for ACC patients, limitations exist and are being improved upon. Eye-to-eye communication is really important and can drain the atrial leadless longevity. Types of tissue is important. Adherence, long-term, and possible clot formation are all important when considering risk versus benefit, right, do they need to be on anticoagulation long-term, is it better to just do epicardial, depending on their prior surgical history. And then the really important thing, too, is you have to use caution with lateral atriotomy scars in these patients, because a lot of us who play, you know, when you place these atrial leadless, and they always say, oh, let's get a better spot, let's go lateral, right, in the appendage. Well, lateral is where your atriotomy scar is. So actually, you're gonna get worse laterally. So just keep that in mind in any patient with an atriotomy scar. And then, conclusion, basically, these types of pacemakers are out there. They're here to stay. They're being used in some patients with congenital heart disease. And there is a possibility of pacing some more complex patients with these. It's just sort of situation-dependent. And patient selection is really important. Thank you, everyone. And I apologize, I'm a little over time, so we'll see if the questions are available or we hold it for now, later. Thank you. Maybe a very, very quick one. Short answer, ideally, about imaging. You showed TEE, that's what you do, that's your standard? There's no ice or anything? So for atrial, I typically do TEE. You could clearly do it with ice, but most of these patients have had multiple femoral vein access. So I try to limit that, and especially if I'm going IJ, then you'd have to use ice from the other IJ or clavian or something like that. So usually I'll do TEE for atrial. For ventricular, I don't think it's necessary at all. And maybe it's not necessary if you have a good transthoracic echo, either. Great, thank you. Unfortunately, we're out of time for other questions. But if you do have questions, please come and see the panelists afterwards, maybe offline. Thank you very much. So now it's my pleasure to introduce our third and final speaker, Dr. Natasha DeGroot, who will talk to us about refractory atrial tachyarrhythmias in our adults with congenital heart disease. Is AV nodal ablation an option? So good afternoon, ladies and gentlemen. First, I would like to thank the organizers for the invitation to present on this intriguing topic, and that is the AV nodal ablation in patients with congenital heart disease. So the first question when I saw the title is that I asked myself, is there really a need for a pace and ablation approach in patients with adult congenital heart disease? This table is derived from the EEC guideline. And you can see here the risk for intraatrial oriented tachycardias, ectopic atrial tachycardias, and atrial fibrillation. And when you take a look at these tachyarrhythmias, you can see that for almost all congenital defects, there's a moderate or high risk of development of atrial tachyarrhythmias over life. The major problem in this patient group is the development of atrial fibrillation, because we know due to the improvement in clinical care that this population is nowadays aging. Another problem is that atrial fibrillation in this patient group occurs at a relative early age. So we evaluated this many years ago in a population of 200 patients and found that atrial fibrillation developed at an average age of 49 years. And you can see here that as a more complex patient group, it even arises at an age earlier than 30 years. Another problem is that atrial fibrillation in this patient group rapidly progresses to longstanding persistent atrial fibrillation. So initially they start with paroxysmal AF, but within an episode, within five years, 26% of this population has already progressed to persistent atrial fibrillation. These patients also have an interplay between a regular atrial tachyarrhythmia and atrial fibrillation. So without any intervention, they switch from atrial fibrillation to a regular atrial tachyarrhythmia or vice versa. The atrial fibrillation in this patient group has then progressed from a trigger-driven arrhythmia to a more substrate-mediated arrhythmia. And that is where the problem comes in, because what is actually the substrate underlying atrial fibrillation in this patient group? Do we know that? Is it comparable to patients without congenital heart defects? Is it located in the left atrium? Because many of these patients have pressure or volume overload of the right atrium. And we see that there is now an increasing tendency to perform a pulmonary vein isolation in this patient group. And this was the outcome of the first international multi-center study on pulmonary vein isolation in patients with congenital heart disease. And it actually showed nice outcomes. It appeared that the majority of this population, so about 65% of the population, were actually free of arrhythmias. And that was even after one or more ablation procedures. And when you take a look at this, in the table which was put in this paper, you can see an overview of all the different ablation approaches they used. And it was not only a pulmonary vein isolation, but it was also creating of linear lesion, targeting low voltage areas, targeting complex fractionated electrograms. But nevertheless, we, and probably you all are aware of that, we do have patients which have a lot of recurrences of both atrial fibrillation and regular atrial tachyarrhythmias. And then what to do? Because we have the antiarrhythmic drugs, but we know that they are not so effective. They have serious side effects, particularly in the patients with congenital heart disease, who have a sinus bradycardia. And then we have the catheter ablation. But if we fail to ablate interatrial entetachycardias, or if we fail to ablate atrial fibrillation, what is then left to do? And this is a table from the recommendations from the ESC guidelines. And if we take a look at this guideline, then we see that atrial ventricle node ablation should be considered for rate control in patients who do not respond to either pharmacological therapy or ablation therapy, and that is a class IIa indication. But in all these studies, pediatric patients and patients with congenital heart disease have been excluded from these studies. So actually, we do not have any recommendation on this patient group for the AV junction ablation. And my talk would have ended if I hadn't had this research fellow. So my research fellow was also here in the audience. Naveen, he recognized this knowledge gap, and he started this multi-center study. And in this multi-center study, we evaluate the outcome of a venodal ablation therapy in a large group of patients with congenital heart disease with a variety of congenital heart defects. Because in the prior studies where I showed you, on the outcome of pulmonary vein isolation, it was also that the majority of these patients either had a bigaspate aortic valve or an atrial septal defect and did not include patients with complex congenital heart disease. So that's also there, another knowledge gap. So we just collected the data a few days ago, so I have only the initial results from it. And so far, we have now 56 patients. Half of the patients is male. The average age is around 50 years. The majority of the patients has a systemic left ventricle, and here you see in the pie the distribution of the different complexity of the congenital defects. And again, a large part is the simple defect, but also we have a considerable amount of patients with the more complex defects of the fontan circulation. This table shows the baseline characteristics, so the majority of the patients were in the neoclassic two. Most patients had a good left ventricular ejection fraction, but also, as you can see here, a considerable amount has a moderate or poor ejection fraction. And dilatation of the atria, either the right or the left or both, was as expected present in a considerable amount of patients. Of course, a lot of therapies has been attempted, and that we see here. So, surprisingly, nearly 50% did not have any ablation procedure preceding the patient-ablase approach, but yet the majority had also, like, two or three ablation attempts. Many had undergone cardioversion, even a considerable amount of patients more than five times. And here also an anterorythmic drug therapy was attempted. Two or more drugs was tested in 32% of the patients and two or more in 28. The onset of the atrial tachyarrhythmia was quite young. It was at the age of 40. It was comparable to the majority of the studies publishing on the onset of tachyarrhythmias. The interval between the onset of the arrhythmia and the ablation procedure was 60 years, and the age at that moment that it was cited to transition to a patient-ablate approach was nearly 50 years. So, what were the reported indications for the patient-ablate approach? Ineffective rate control therapy, tachycardiomyopathy, and inappropriate ICD shocks in 11% of this patient group. Of interest is that nearly half of the patients already had a cardiac implantable device, so 37% already was paced in the ventricles, and 10% had cardiac resynchronization therapy. So, the other 29 patients received their first device before the pace-in-the-blades approach, and in this patient, 30% had cardiac resynchronization therapy, and either VVR or DDD pacemaker was implanted in nearly 70% of this patient. Three patients received a leadless pacemaker, and conduction system pacing was performed in one patient. So, what is then the outcome? Despite the complexity of the congenital defects, acute procedural success was almost 98%. As expected, the AV junction was located at abnormal location in 26% of these patients. Most procedures were performed on the local anesthesia. 3D mapping was used in nearly 50% of the patients, also indicating the complexity of these procedures, and in 7%, remote magnetic navigation system was used. This slide shows the long-term follow-up. So, we have a follow-up of nearly 10 years. Three patients received a heart transplantation. The other six patients died, and at the 10-year follow-up, we have an arrhythmia-free survival of 65%. So, the other outcomes, that was also that 11% required a lead revision, that's quite high. The left ventricular function remained stable over time, because we were also very much afraid of the pacing-induced cardiomyopathy, but here it remained stable, and an ER cluster also improved over time. So, it's still preliminary data, and we're now digging further into this, but what can we conclude so far? I think we can say that there is a high procedural success, and of course, we have to take into account the technical consideration, and the difficult anatomy, the preparation, the use of a 3D mapping system to identify the his bundle. There's a reasonable long-term survival. There's a decrease in symptoms, and also importantly, there's no decrease in the ejection fraction. This has already been highlighted by the previous speaker, but I think it's also important that if we think that now right ventricular pacing is already, does not result in a pacing-induced tachycardiomyopathy, think also about the leadless pacing, particularly because we have a lead revision rate of 11% in this patient group, which is quite high. And also, another thing is that the pacemakers, the leadless paper, can be very elegantly implanted via the jugular approach, so if you have problems with cardiovascular access to the heart, this might be an alternative approach to use. So what is the take-home message? There's very limited experience in the base and the blades approach. If I put it in PUGMA, you will find at this moment zero results. There's a technical complexity of the procedure, and you might expect displacement of your AV node or your bundles of his due to the congenital defect. The anatomy is distorted, so that might hamper your catheter position, but it might be aided by a three-dimensional mapping system. There might be limited vascular access. The pacing-induced cardiomyopathy is something we are always afraid of, particularly in a patient with congenital heart disease, but given the area that now we use, condition system pacing and left bundle branch pacing, that might even further improve the treatment, though our results of the study do not indicate that there's a high risk of pacing-induced cardiomyopathy over a period of 10 years. And of course, for the lead dysfunction, the leadless pacemakers now offer another treatment modality. So this was the end of my presentation. I would like to thank all the people who are on this slide who actually provided us for studies, a patient for these studies, and I think, yeah, this is an important area which needs to be further investigated. Thank you for your attention. Thank you, Natasha, for a wonderful presentation, and thank you and your fellow for leading this international project on an important question. Any questions from the audience? Maybe I'll start. You know, I think a lot of us are, including myself, are very hesitant to ablate a navy node in certain subgroups, such as Fontan patients, and systemic RV patients. And we know in Fontan patients, once you start, if ventricular pacing is associated with poor outcomes, an eight-fold increase in adverse cardiovascular events, and the more you pace the ventricle, the worse the outcomes are. I saw that in the study of 42 patients. I think you have eight patients who have either single ventricles or systemic RVs. It's not a big number, but any insights that you can share about that patient population, and perhaps also comment on, you know, epicardial lead placement, what you would recommend for those patients? Yeah, this is a very challenging patient group, I admit. The first thing I would like to say there is that a lot of people forget that we don't understand the mechanism of AF there yet. So, yeah, pulmonary vein isolation now is something we would not like to do in this patient group because that's even more complex. But also, I would really like to recommend people, before they decide to go for a patient-ablade approach, also look into the mechanism, because in one patient, I just accidentally bumped onto an area with complex fractionated electrocardiograms, with continuous electrical activity, while the remainder looked something like an intra-atrial antitachycardia, and by encircling that area, AF terminated. So that would be my first remark, and the second remark, the problem is that we don't have anything else to offer to these patients. So, yeah, and you could say, yeah, you could immediately provide cardioresynchronization therapy instead of just putting in a VVI lead in. You could think about conduction system pacing, but, yeah, where is the conduction system? It's probably quite different compared to the other patient group. So, yeah, it's very difficult to give a recommendation because there's so much we don't know in this patient group. Thank you. Yes, a question. I have a question. Dovetails are leadless pacemakers, and probably actually more relevant for the ones that are not put in for permanent AFib, but I'm curious, as we're starting to use these more, and especially microAVs for ventricular pacing, what you're seeing in patients with atrial myopathies, you know, like Mustard's or Fontan's, as far as the actual AV synchrony, I think that that's one thing. The micro will tell you it's doing great, and maybe it's not actually doing quite as well. So I'm just wondering if you guys could comment on that. Great, thank you. We have about two minutes left, and maybe Natasha will just invite you to take a seat here. And in the final two minutes, there are some questions that have come in from you all. We'll try to get through some. First question here is for PFA. How close can you get to the AV node when you're using PFA? All right, this is a good question. So we know that the PFA lesion develops directly underneath the catheter, so there is probably no long-standing extension, no permanent extension beyond the catheter. So when I use PFA, first, before I apply PFA, I do a rigorous mapping, not only looking for substrate, but also for the specific conduction system, and then I just stay away from the conduction system. And in doubt, I don't use PFA, but use cryo, as in the one front-end patient. Thank you, Mende. One final question. This is for Natasha. Why is there a high percentage, 44% of patients, that did not receive any ablation before the AV nodal ablation in your study? Yeah, that's quite a surprising finding. I have to admit, we have to look into that, because we just have the first numbers coming out. I think there are still people hesitating to refer people for ablation of either in the regular AV nodal ablation, because there's also people with AV nodal flutter inside the day who did not get an ablation procedure. And I indeed agree, that's quite surprising. But a clear explanation at this moment, I cannot give. Can I answer the other question real quick? That lead us to a question? I think that's a really important question, the AV synchrony, just to come back to your question, because I do think it's, in general, overall, the same or worse. So I do think we're setting them up a little bit for that, depending on the patient population. And also, I think really knowing where we place it is important to really hit that one, at least hit one degree of the accelerometer. So I do think, for instance, I have an unrepaired tetralogy of a low patient who came in, attempted repair, failed, had an outside institution, had still his big old VSD, left to right shunting, but really had had three kids already. It was in her 60, I think, 61, something like that, but was having a complete heart block and Stokes-Adams attacks. And so ended up doing a sort of urgent micro-AV2 in her, because she didn't want to go through a bigger surgery, right? Epicardial, all that stuff. But that's sort of closer in the outflow track on the way out, and I think the AV synchrony there isn't as great. So I did encounter that. Maybe we're hitting the 70s with that, mid-70s for AV synchrony, versus we really should be hitting higher, because I do think these patients are more prone to atrial myopathies, especially after all the atriotomy scars and such. It's a good question. I fear we have to come to the end of this session. I think it was quite exciting. We learned, I think what I learned was PFA is here to come and stay, and that's something that we need to go and apply in our patient cohorts, probably with a focal catheter a little bit more than a large footprint catheter, is my personal view. Needless pacing, for sure. Also an absolute option for our patients. Has so much potential to sort so many of the basic problems out for these young patients who have to go through so many interventions otherwise. So stay tuned, enjoy the Congress, and, yeah, thanks for coming. Thank you.

cardiac technology

congenital heart disease

pulse field ablation

catheter ablation

leadless pacemaker

atrial fibrillation

AV nodal ablation

arrhythmia

dual-chamber pacing

refractory atrial tachyarrhythmias