This one, I want to thank Shu and the organizers for putting this session together. And this is an interesting session that I think when the title of it is sort of K-pop meets classic rock. So for those of you who don't know what K-pop is, since I went to the Korean Heart Rhythm Society meeting last year, K-pop is like, it is the all B in South Korea. These are like rock stars, movie stars, music aficionados, and groupies follow all these people around. And I think we all know what classic rock is. So today we have two senior people. I can tell you which category they're going to be in. And then two junior people. So anyway, without one, also we want to wish Sabrina the best. Sabrina was supposed to be here, but had an accident hiking and is casted up and booted up and everything else. So hopefully she'll be on her way to recovery. Anyway, who is going first? Dr. Walsh, who needs no introduction, who's I think going to be going with a little Rolling Stones, Who, Foreigner composite. Well, boy, I am the perfect guy for this talk, I must say. I have a few confessions. I used my flip phone until the battery wouldn't hold a charge anymore. I still prefer fluoro over ice for Brock and Brow. And there's a lot of equipment that I used in our lab for a long time that's no longer available and I sort of miss it. I guess what I'm trying to say is if something works really, really well for me, I'm reluctant to abandon it just because it's old school. And I think point-by-point mapping for accessory pathways not only works well, but I think it's the gold standard for accessory pathway ablation. Ablating pathway has come a long time in my career and especially the reduction in x-ray that accompanied 3D electro-anatomic mapping. But make no mistake, the top line in every EP study is still the humble electrocardiogram, a technology that's been around for over a century. And all eyes still focus or should focus on the electrogram that's recorded from the ablation catheter tip when you're trying to target a pathway correctly. And yes, there have been some great advances in mapping. There have been some great advances in ablation. But what I always try to stress to our fellows is it's not the technology that you use, it's understanding the biology of your ablation target. So here's a really cool thing. This is a open window, high-density map of a post-receptal accessory pathway. And I got to admit, that's a really cool thing to look at. But now what? The post-receptal space is very complicated. And into the bargain, you have to remember what Dr. Jackman taught us, 90% of pathways in this area are oblique with a long course with a ventricular insertion rightward and the atrial insertion leftward. And look here, if you just go by activation time, you could get fooled with an oblique pathway because what you really want to target is the accessory pathway and not necessarily early activation. And you also have to remember that sometimes in the post-receptal space, you will encounter diverticulum. I still routinely do an angiogram in the coronary sinus during anything that maps in that area. And I think Dr. Fishel probably mentioned something similar during his talk. But all that can make it pretty complicated. And you have to choose which direction you're going to come at the pathway from, even when the coronary sinus anatomy is regulation. So you could come from the right side. If you're lucky, you'll get it there. But that doesn't always work out. You may have to go into the coronary sinus or the middle cardiac vein where there's always concerns about the nearby coronary artery branches. Or you could go over to the left side and ablate there, even though the access is a little more complicated. So how do you decide? Well, take a look at the signal here. This is the site of success for a post-receptal pathway. And there's certain things to point out. There's a little high frequency feature that I think is a probable accessory pathway potential. And you'll notice that the ventricular timing is not terribly early there. That's because the ventricular insertion is over on the right side and I'm on the left side of the septum. But nonetheless, that was the signal that worked. Notice I said potential or possible accessory pathway potential because I don't always go through the rigorous verification things that Dr. Jackman developed. But just going by activation time, knowledge of the anatomy, and those high frequency features, that's held me in good stead for a long time. This is a case of PJRT, for example. And this is from a long time ago. This is when we were still using analog amplifiers for EP signals. And we found that for PJRT in the post-receptal area, there was a very distinctive electrogram feature that usually predicted success. And it was there in all the cases, that little extra potential that preceded P wave onset. Now here's a contemporary PJRT case. And there's that beautiful electroanatomic map that shows you that the area of interest is either in the mouth of coronary sinus or down the middle cardiac vein. But if you look at that electrogram, it's got the same darn features as what we published decades before. It's that little extra potential. You'll notice this is kind of a noisy signal when I blow it up. That's because it's a digital amplifier. Those analog amplifiers were beautiful, and I miss them as well. So you can't always do detailed activation mapping. Sometimes there's anatomic challenges that preclude that. And here's an example. This is a 29-year-old with a single ventricle heterotaxy, a double inlet single RV. There was an interrupted IVC, and a Kalashima was done after he developed pulmonary AVMs. He had a conduit from his hepatic vein to his RPA, which really helped things. But his whole life, he had been plagued by orthodromic tachycardia due to a concealed pathway over the left-sided tricuspid valve. And he had five prior ablation attempts, all at a first-rate center by experienced folks. Difficult access, one transhepatic in two of them prior to the conduit to the PA. And they went transbaffle from the SVC in the other three. Most of these had success, but recurred. So when he was sent to us for another try, we knew we had to do something different. So we settled on a retrograde approach and coordinated that with an MRI shell. And fortunately, we got lucky, and this took care of the pathway. But all we really had to go with, given this complex anatomy, was the tip signal from time to time. And fortunately, we found a good one. So you can't really depend upon activation mapping all the time. And what about atrial fascicular pathways? Well, this is another situation where activation mapping doesn't help you. You can't look for atrial insertion by conduction activation time, because these are antegrade-only pathways. And the ventricular insertion down towards the RV apex doesn't do you any good. There's one and only one signal that you want to look for. And remember that these pathways are very prone to mechanical bump. And if you spend too much time banging around with an octopolar catheter or a grid catheter, your case might be over. So I think you've got to work quick. And as soon as you see this telltale electrogram that suggests the atrial fascicular pathway potential, you really have to act. So point-by-point mapping is important there, and you can see this was a successful ablation during a lateral right atrial pacing. The delta wave goes away, and there's normal conduction. Now, not all the electrograms recorded from the tip are as clear as the ones I've just shown you. And nowhere is that as common as in Epstein's anomaly. The signals that I'm showing here are during orthodromic tachycardia from a concealed pathway. And we were unsure where the atrial signal really was. We took a lot of point-by-point samples and finally found one that we wanted to try. With ablation, I wasn't sure which of these components here was atrium, which was ventricle. But you can tell during successful ablation that the atrial signal gets a little bit later, and then it finally blocks, and this was a successful ablation. So if you understand the biology of Epstein's, this makes perfect sense. That ventricular electrogram is split, it's low amplitude, and that's because you're dealing with atrialized ventricle along that AV groove. You can't expect it to be sort of a common AV balance as you would see in a normal heart. So you've got to define the AV groove in other ways, too. You can't go by the ventricular amplitude, and you either need angiography or ice. And then that tip signal never lies, but you've got to get the catheter to the spot. And this is another illustrative case. This is an eight-year-old who I took to the lab who had a high-risk left anterior WPW pathway, recurrent tachycardia, and the characteristics of that pathway were kind of scary. I tried to ablate twice before along the anterolateral mitral annulus where I had had early activation. And although we had maybe a very transient success, he left the lab still pre-excited. When I brought him back at age eight, I think the reason that I was so confused is I could never get the catheter out the coronary sinus to bracket the area of interest. And we used a Cardema catheter, that little 1.4 French catheter, and I was able to snake that out there and actually record accurately along the AV groove. But when I put the catheter tip in the left atrial appendage, it was earlier there. And it beat anything along the true AV groove, and we finally figured out the biology here. This was not a standard accessory pathway. This was an appendage to ventricle pathway. We tried to ablate the best we could using both RF and cryo. We even tried to isolate the left appendage to no avail. So we took this boy to the operating room. And as the surgeon dissected the left atrial appendage off the summit of the left ventricle, you can see the delta wave just melted away, and that was the end of the problem for this boy. Now I may be an old dog, but I am open to new tricks. And when John Triedman and I first started ablating atrial flutter and congenital heart disease, we didn't have the luxury of 3D electroanatomic mapping. We used to go by point-by-point signals, angiograms to give you that little contour of the different chambers. We would do post-pacing intervals. And it worked, but it was quite tedious, and the outcomes weren't great. So as soon as electroanatomic mapping came along, it was embraced very early in our lab. John became a master at it. But it's the right tool for the right job. And point-by-point mapping, that never lies, but it depends upon the biology of the arrhythmia that you're treating. And we're all used to seeing an atrium look like this. I think we would do well to remember that an atrium actually looks like that. So to conclude, use whatever technology you want to get the job done, but don't ignore the basics. And for accessory pathways, at least, that signal at the tip of the ablation catheter, I think, is what really counts. And the major challenge with any ablation procedure is understanding the underlying biology. Thank you. So, after listening to Walsh talking about point-by-point mapping, after listening to Walsh's wonderful presentation, now let's turn to K-pop. And I would like to introduce Iqbal Asad, actually from Cleveland Clinic, and she will represent our generation to talk about the high-density mapping. So let's do it. Thank you. Thank you to the organizing committee for inviting me. I don't have any relevant disclosures for this talk other than the fact that I'm not a high-density mapping expert, but I learned a lot preparing for this talk. And so, my hope over the next 12 minutes is to review what high-density mapping is and how that differs from conventional mapping, review the various high-density mapping catheters available, discuss a few cases that highlight the benefits and limitation of this technology for mapping accessory pathways, and review the current literature on high-density mapping for accessory pathway ablations in children. And so, as we all know, high-density mapping is a process of simultaneous acquisition and annotation of multiple electrograms by an automated algorithm. And this is because manual scrutiny of signal is difficult due to the large number of collected points all at once. And typically, this is achieved using a multipolar mapping catheter that has smaller spacing electrodes than the conventional mapping catheter. And that's important because then it helps us with signal quality and improves spatial resolution. And the other unique feature about high-density mapping technology is that it's less dependent on the operator interpretation of signals. So, each 3D mapping system has developed its own multipolar catheter. This table shows the various available high-density mapping catheters and their corresponding electroanatomic systems, and also highlights the unique features of each one of them. But as you see, they have their own unique design, but in essence, all provide a significantly higher number of EGMs per map at a significantly higher acquisition rate than point-by-point mapping. And relevant stuff to children is the size of the catheter. And in terms of that, the Pentarray is the smallest one. It fits through a seven-and-a-half French sheath, which is, again, important for children just thinking about access site injury. And the other important thing is that all of them, except for the Pentarray, require anticoagulation with an ACT of greater than 300, even if you're mapping on the right side. So, again, keeping in mind potentially the added risk of bleeding and hematoma. And in terms of the specific mapping technology used for accessory pathways, it's known as open-window mapping. I'm sure you've all heard of it. And the premise of open-window mapping is that it allows physicians to visualize the accessory pathway connection by highlighting a breakout point in the annulus. And the way it does that is that it generates a color map that depends on the difference in the local activation time. And if there's a big gap between the two, then it's going to highlight that as a white line if you're using CARDO. And the higher the point density, the better the resolution. So that's why for an accurate open-window map, you really ought to use a multipolar catheter. And so how is the setup different compared to conventional mapping? So in contrast to conventional mapping, where the system or the experience provider would identify and annotate the earliest local ventricular electrogram when mapping in sinus or in apace rhythm or the earliest atrial electrogram in ORT or V-pacing, in open-window mapping, what you have to do is set what's called a window of interest a little bit differently so that it analyzes both the atrial and the ventricular signals simultaneously, which is what's shown here in this figure. And then what the algorithm does is that it annotates the signals automatically based on the highest negative dvdt at each point. And so you can see that here in this first example, it decided to annotate the ventricular signal because it had the highest dvdt. And then in here in this second example, you see a high-amplitude atrial signal with a far-field V signal. And so the algorithm decided to annotate that. So moving on just to review a couple of clinical cases, this was a case of a five-year-old female who had recurrent SVT requiring hospital admissions despite medical therapy with propranolol and fluconide. So we decided to take her to the EP lab and do a catheter ablation. During her first EP study, she had no dual avenodal physiology and no inducible SVT despite testing at baseline and with isopryl. Her retrograde conduction was nondecremental and adenosine-resistant. And we kept seeing those single reproducible echo beats with atrial extra stimulus testing with the earliest atrial signal on the hiss catheter. And so suspected that, you know, the most likely mechanism here was ORT using a concealed parahissian pathway. And unfortunately, halfway through the case, while mapping, those echo beats were no longer present and we suspected that at some point we had mechanically injured it. And the case was concluded without ablation due to a lack of target. Of course, four days later, she comes back and she has the same thing, gets admitted to the ICU and started on an asthma-old drip and we decide to take her back to the EP lab. And this time, we decided to map with the Pentarray for two main reasons. One because we knew the likelihood of inducing SVT and mapping that was going to be low given the findings of the first study. And here you can see that at most we had three echo beats. And so the Pentarray allowed us to rapidly acquire data. And the other reason is to avoid mechanical injury of the pathway, just like what happened in the first case. And, you know, the reason the Pentarray typically, the splines are pretty flexible and they were way less atraumatic than the tip of the ablation catheter. And with that, it was mapped to the anteroceptal region. And so after identifying the earliest point of activation, we advanced the ablation catheter. And as soon as we put it there, it was again mechanically bumped, but we had already mapped the area of interest and felt comfortable ablating there while monitoring the AV conduction closely. Fast forward two years later, she is SVT free and on no medical therapy. So the highlights of this case is that the high density mapping here allowed for rapid and effective mapping of the concealed accessory pathway without mechanically injuring it, resulting in a successful redo procedure. Not too long after that case, I had a 14-year-old with asymptomatic WPW but persistent pre-excitation whose ECG here suggested a right anterior interoceptal pathway and I was worried about mechanically bumping it, so I decided to use high density mapping. And here in this still image, you can see that there's a lot of density points both on the atrial side and on the ventricular side. This white line represents the annular border. But if you look here, there's like a wide breakout point. So my question initially when I saw this was, do I ablate here, do I ablate here, or do I ablate here? And here on the right-hand side, you can see the propagation map essentially showing the same thing that there are potentially multiple breakout points. And so this is when we decided to go back and look at the signals. And the signals between 10 and 11 o'clock around this region, everywhere we looked looked like this, this low amplitude far field signal. And so of course, you know, the automated algorithm didn't really know how to best annotate this. But if you compare that signal to the signal at the site of success here closer to 12 o'clock, you can see that you had a nice fused AV signal. And so we like this signal. and as soon as we advanced the ablation catheter there, we bumped it, retracted it, advanced, you know, slowly and waited for the pathway to recover and ended up ablating here and it went away within two beats. The highlights of this case is that open window mapping was helpful in quickly identifying the region of interest without mechanically injuring the pathway, but it gave us a relatively broad area of breakout due to inaccurate annotation of the signals in the setting of poor contact. So ultimately, you still have to go back and map and refine your map with the ablation catheter to truly confirm the site of success. And the third case was a case of a 13-year-old with trisomy 21 complete AV canal defect that had a repair using a single patch technique in infancy. He also had WPW and persistent pre-excitation. And so an EP study, a couple of unique things about his EP study is that his coronary sinus, the way that the AV canal was repaired, it was in a way that the coronary sinus drained into the left atrium, so we didn't have a coronary sinus catheter as a reference and nowhere on the right side could we find his signals. But started off with conventional point-by-point mapping and it showed us that the earliest point of activation was along here, the posterior lateral region, which was a little bit surprising because looking at the ECG, we had suspected a posterior septal region. If you look at the signals here, like, yeah, this is an early ventricular signal and it was about 18 milliseconds ahead of delta wave. Contrast that signal to the signal on the septal side, that wasn't, you know, as early. And so with that information, decided to ablate on the posterior lateral region. And of course, after two tests, ablation lesion, there was no change. And so at this time, we decided to use open window mapping and perform the repeat map using the HD grid, again, in sinus rhythm with pre-excitation. And interestingly, here, these still images show that there are potentially two breakout points, the posterior lateral region as well as the septal region. So it looks like the automated algorithm fell into the same trap as we did when we initially were mapping it. And here's just a propagation map. If you focus here, you can, again, see that there's earlier activation along the posterior septal region than compared to the posterior lateral region. And when you look at the density map, this is the region of interest, the posterior septal region. And there really didn't have many points there. And so at this time, we wanted to investigate this area and understand the anatomy better. So ended up actually using ice. And the anatomy was significant for this big tricuspid valve ridge that really limited catheter reach in mapping of that region. And so once we figured this out, ended up advancing the catheter, as you guys see on the fluoroscopy image here, into the RV and retroflexed it under the tricuspid valve annulus. And now, all of a sudden, you have nice annular fused signals that we weren't seeing earlier. And this is the signal at the site of ablation. And here, in this video, you can see that we had immediate loss of pre-excitation. So open window mapping here was helpful in the fact that it quickly showed that the accessory pathway breakout point was septal. And so we refocused our attention to that. The whole map was limited by the lack of points in the septal area of interest. And what we suspect was happening along that posterior lateral region is that those were actually fractionated atrial signals and not V signals. And so ultimately, understanding the anatomy is key. And just remember that the maps are as good as the data provided to the automated algorithm to interpret. So what available literature do we have on this topic in pediatrics and congenital heart disease? There's really not that much. A bunch of case reports and a single case series that was published by Johannes in 2022. But you can see that there's a lot of interest in using this technology in Epstein's patients. Not surprising given the fact that these are some of the most challenging cases due to distorted anatomy and fractionated signals. But what's lacking in all of these publications is the long-term success, whether this technology is going to, you know, improve the long-term success. And so in conclusion, high-density mapping of accessory pathway gives you the zip code, maybe the street, but not the exact house number. You always have to go back to the basics and confirm the exact location with mapping around the area of interest. And whether this technology adds considerably to conventional catheter-based mapping is not clear as of now, but I think it's useful in cases where you have non-sustained arrhythmias like the first case, in cases where you're worried about easily bumping superficial pathways, and potentially in congenital heart disease where the local activation is difficult to annotate. Thank you. One last thing, special thanks to Akash and Pete for being so generous in sharing their cases with me to present today. And special thanks to Brian and Angelina, who are our biosense webster and insight mappers for providing the videos. Our next speaker is a major, major music aficionado who just found out participates in four different bands, and of course he lives in Nashville, so Frank Fish, who's at Vanderbilt, is going to sort of talk about the continued need for fluoroscopy and radiation for all of us. All right, well, thank you to the organizers for inviting me, and that's a nice introduction. I hope maybe some of you came and heard us play last night with Bill Stevenson's Dysrhythmic Band. I don't think I was asked for this talk because I play music. I think it's because I'm getting older. And I'm much like Ed. I hold on to things at work for a while, but I'm also, Arthie likes to tell us, I'm a new, I'm an early adopter. So did my thing come up? They're missing my, oh, oh, here's my disclosures. I have no financial disclosures, but all the songs I'm going to feature, I have played on at some time or another in my lifetime. I also have never played on Dancing in the Dark, a Bruce Springsteen song in a cover band, so that should have been the lead article, but I didn't. So let's talk about how we started, because I think that is pertinent to this talk. I learned to play bass most by playing Chicago stuff. So the way we were when we started, it was no fun. That's really loud. So we had an E4M recording system in our shared EP lab with adults that we used primarily for just diagnostic studies, SVT studies and VT studies. And when we got our first RF generator, we turned it on for our first case, and it completely, everything went noisy, including the surface EKGs. The filtering just wasn't sufficiently robust. And so we looked around, and we had this catheter recording system called the Siemens Minkograph, and it had a little add-on you could do. It was mainly designed just to do a HISS bundle recording. Back when that was, you know, EP, all there was to EP in the late 70s, early 80s. It had seven channels. Three were devoted to surface EKGs. So we had four bipolar intercardiac channels. That was our EP system. We had that. We had our hands. We had fluoroscopy. We averaged about, I went back to try to get the exact number, but they're not recorded in our database that early, but we averaged about 30 minutes of fluoro time for each case. So that's a lot by today's standards, by no question. But we did pretty well. Our first 50 SVT ablation in children, we had 48 acute successes. Not counted in that one was an EAT case that Ed came down and helped us with in that era, and we had that system. I don't know if you recall, but that's what we had for our first couple, three years, and we finally got to go up. So we're using a lot of fluoro, but how bad was that, really? We unfortunately tried to do a, wasn't it, what was it, a Pediatric EP Society study, and several participated. We put TLD crystals on, and for a lot of different reasons, we never really could come up with any kind of good conclusive information to report. But there were some data published about fluoro. How bad is fluoro? We all know about Olara. We were supposed to minimize, and no fluoro has become kind of the mantra in many, many instances. Well, the attacker ablation study, which, interestingly, is the only study that was ever done that I'm aware to actually prove safety and efficacy of intracardiac catheter ablation system until now we get into the pulse field stuff. But they looked at 859 patients in that study, included some pediatric patients, a lot of fluoro time. Twenty-seven percent of patients had over one hour of fluoro, and this was an area where post-fluoro was not really coming into vogue. Most systems people had were continuous fluoro. They had over 150 minutes in 5 percent of patients. Interesting longer time for males. This just shows the distribution of their cases. So about half of them were less than 30 minutes. But what they calculated, despite these high doses, the best they could do with the technology had estimated lifetime malignancy risk, 0.14 percent in females, 0.22 percent in males. A high proportion of patients had high enough dose that they could have potentially been causing a cutaneous injury, although how many actually had that is not clear. Fortunately, and this may have to do to the pediatric centers involved specifically, the exposure was lower in the younger population in that study. There was another study that came out the same year. They put more crystals on to give some more accurate estimates of exposure, and that, for 60 minutes of fluoro time, their estimated risk of lifetime malignancy was 0.03 percent. Sixty minutes of fluoro, 0.05 percent. We all have a 20 percent background risk of malignancy in our lifetime. So it's really, even this very tremendous amount of fluoro exposure is a fairly negligible additional risk. Not advocating we do an hour of fluoro, but just sort of trying to put things in perspective here. The most accurate way to determine organ exposure is by using anthropomorphic phantoms to replicate the anatomy for the specific patient. In this study, that's what they did, 24 patients, they used a lot of crystals, and that came up very similar to the last, 0.06 percent, and it's interesting, it was different between the U.S. centers and the U.K. center involved, but 0.06 percent on top of our 20 percent per 60 minutes of fluoro time. The genetic defect risk that that may have exposed the patients to was also extremely low. And that's, this is 6 percent background risk of that. So fortunately, we've come a long way. So a lot of new things have come about, and so we get to enjoy the new kids in town, all the new stuff over the years that we've seen since the very beginning. We got post-fluoro, which helped with image holds, stored fluoro, our fluoro times start to plummet, multi-channel recording systems become available, electroanatomic mapping soon followed, our high-density catheters, ice, which we're going to hear a lot about. We also often use image integration, as Ed's case showed, get a CD, excuse me, CTA or MRI, and some centers may use fluoro spin, or you can use image integration in a lab with ice. All this stuff, we always use these things. I haven't had a chance to have magnetic navigation, but, you know, another innovation. So then the question I'm asked is, I love this song. So is there still a role for fluoroscopy? Well, I think yes. It's undisputably feasible to perform a large proportion of ablation procedures with zero fluoro. And I think that's fine if you remember that it's not a crime to step on the pedal. Fluoro doesn't necessarily mean no fluoro, because sometimes it's reasonable to use fluoro. And so the question is, should we be advocating for no fluoro versus minimal fluoro? I don't think there's anything wrong with no fluoro if everything's going fine, but when things aren't fine, I think you really need to investigate further. So I was supposed to give you some reasons for doing fluoro, and so we will. So we'll start with proximity of ablation to vascular structures. And I alluded to this further, and I like this one, too. So here's a case that was sent to us, a patient with a previously failed RVOT ablation that they had done a lot of lesions from this area here on the right ventricular alveolar crack septally. And we did the same. There are a couple of ablation lesions in there. And we mapped it using a catheter all the way around the CS into the anterior intermediate cardiac vein. It was really ludicated on the summit near that vein. But as Bill Stevenson has taught me, you've got to be certain you know where the coronary artery is. So we had our partner do a coronary angiogram. And the place that we were originally going to ablate was 0.2 millimeters from the LAD. So we were able to pull back just a little bit. It wasn't quite the best signal, but we were able to get enough RF into that area. If we had just gone by without the angiogram and the fluoro involved with that, we could have caused a significant coronary injury potentially. Similarly, as Dad alluded to, a patient with posterior septal pathway that mapped earliest in the middle cardiac vein. So this was one of Andy Radbill's cases, and he wisely did an angiogram. And again, saw that by adjusting back a little bit and focusing a little bit more on the going a little bit rightward, and not at the earliest site, but at a site where we think the pathway. In fact, I think we had a pathway potential. We were able to successfully ablate there and avoid delivering energy close to the coronary artery. So maybe you could do that with ice. I don't know, but I certainly wouldn't feel comfortable knowing exactly where I was with ice alone. Others with more experience might. We all get stuck with the cases where patients have either heterotaxy or traumatic elimination of access to venous access. So sometimes we've got to figure out, well, how are we going to get there? And I think that another good song, played this in college, didn't play for very long. So this is an example. This is a gentleman that I follow who has dextrocardia, interrupted IBC, very complex enema. He had a microbiome replacement. He had atrial flutter that we had presumed would be perimitral. In fact, we were almost certain of that, and it turned out to not be. It was on his left-sided right atrium, kind of a variant of CTI flutter, but without a real CTI. He had had a previous ablation several years prior for atrial flutter. We had gone through the liver from a right-sided approach because that seemed to be where his liver was mostly left-sided. And despite delivering coils, he had hemoperitoneum and had to have like five blood transfusions before it finally just sort of stopped oozing. So he was not excited about another trip, another such encounter, but he was having a lot of flutter that we were having trouble controlling. So we got a CTA, and our cardiac imaging guy called and was excited, said, hey, I think I see how we can get into this heart. And this is the angiogram I've outlined, as you can see it. But you're coming up through an asgus vein into the liver, and then takes this very serpiginous course through the liver, into hepatic veins, and finally into the heart. And I don't think there's any way we could have gotten through there without flurrowing that area, but we did. And with that, interestingly, that whole course kind of straightened out like this, so it's much easier to maneuver with a long catheter once we had a sheath in there, and we were able to deliver a line of lesions and successfully ablate his flutter. This, I don't know why I showed this. This was coming down from his SVC. I think I was to show that if we come down from above, it would be very hard to get into that area we need to get. And then this is a PVI ablation in a patient with heterotaxy, prior AVSD repair with a left IBC. And again, we were able to get up and through the liver into the rightward atrium. But the problem is we couldn't maneuver our balisk sheath into that area, so we had to use a Broca-Brown needle, and he only had one patent vein from below, and so we really didn't have another access site to put ice up. So again, this was done under flurrow and achieved successful ablation. So sound has its role, heard it through the grapevine, but come on. This was supposed to go better. I don't know why I can't get this to play. Okay. Let's stay together, okay? Let's be friends. So flurrow versus ice. No doubt that ice has some great advantages in certain places. I think these days we don't need, unless there's like the case that Cabal showed where you have an anatomy you didn't realize was there, a catheter positioning, we can use our electron atomic mapping, no problem. But with complex positioning, such as a papillary muscle VT or retrograde approach to tricuspid valve. How am I doing? Am I done? I'm almost done, sorry. Okay. I'm going to conclude. Well, I had, so real quickly, I think ice certainly has a place for some of these more difficult sites. Transhepatic access, I think flurrow is absolutely necessary. I hit the likewise thing at epicardial access. It's the way to go right now, although there may be systems that make ultrasound a little bit better to do that than there were, but I still use flurrow for those. So puncture, I think it's dealer choice. I'm like Ed, I prefer flurrow. It takes me almost as long to get my ice catheter into a position where I can even see my needle and I'm already across. And I just use a tiny little puff of contrast just to make certain that it's where it is if I use a needle. More often than not, I'm using the verse across. But a complex transept, I really think, I like fluoroscopy, although sometimes you can see if there's a septal patch, you can see where the patch is thinner or you have atrial tissue go through. Either might be useful there. Pulmonary vein localization, I use ice just because that's the thing to do, but frankly, I think I rely as much on getting my catheter into the veins to verify on that because sometimes what they mark, I think, is pretty shaky. Inspection of left atrial appendage, though, for clot. Ice obviously can do that and flurrow can't. We have pacing leads in patients. And so you can kind of see if you're kind of maybe bouncing around a lead, but I think sometimes seeing where those pacing leads lie is important when we're going there. I didn't know if it was obvious. This is a Uniview system, which CARDO has available. and so what we do, we do a single frame fluoro at the start of each case and then our cartos superimpose that. So if we have pacing leads, and maybe that's part of what's shown here, this guy has a bunch of leads, including one coming down through the coronary sinus. We know where those leads are. We know where we need to be careful about. So let's be friends. I'm not trying to advocate against ice, but I think fluoro used judicity still has a role. Despite all the advances we have, I think, including ice, I think that sometimes you still need to step on the pedal and make sure you know where you are. Ice certainly has a learning curve, and maybe I'm not patient enough to learn it better. I know Ted's going to prove me wrong here in just a second, but I also don't like the fact that it takes up a vein in patients that you may have limited venous access. And I at least find that the more challenging the anatomy, the more challenging it is to interpret the ice images. So I think having both handy is a good idea. And I have two very quick audience participation things that, I don't know if you guys have the deals, but so which of them is true? For some of you, none of you recognize these old songs I played? B, I played on all of these at some point? C, I'm really looking forward to K-pop? A and C? All of the above? So do you guys have the deals or just show the answer? All right, answer is B if you play, will listen to. Not looking forward to K-pop, but anyway. Oh, that's the poll. We'll go, I'm running out of time, let's go see if people answered it. Did anybody have the poll-y thing, or do you guys have those things? Oh yeah, okay. All right, so okay. All right, that's good. Well, I thought it was B, but I'm wrong. So the second one, this is harder. I played bass on all of those songs except The Way We Were. I did play on The Way We Were one time in a performance. So what instrument did I play? Clarinet, bassoon, French horn, cello, or the glockenspiel? That was a very prominent glockenspiel part in the background, if you know that. So we'll see if people get this one, and then I'll get out of the way. All right, so I played bassoon in high school and college, and I actually played in the Belmont University Orchestra after succumbing to Vanderbilt for a few years. So I was a bassoon player. This is our cardiac surgeon, David Shell, in the bassoon. Thank you. Hello, hello. So thank you, and I think it's my honor to introduce Ted Oulani from Boston Children's Hospital. I think he is the best to represent our generation to talk about ultrasound use. And actually, I met Ted last year, and I spent a few weeks' time with him in the EP lab, and he saw himself as actually easy to do the transceptor without any fluoroscopy. And I actually bring back the technology to back to my Hong Kong EP lab. I'm really thankful for that state. And I turned over the time to talk about the shades of gray with ultrasound, and thanks, Ted. Thanks, Adit. That was far too kind. Thank you all for having me. So the title of the talk is, as you see here, shades of gray, and this is not going to try to replicate what Frank just did, which was a tour de force, pros, cons of ice and fluoro across many different types of cases. This is really going to be one case of a very specific rare anomaly that kind of showcases and ties in all of these technologies that these folks have talked about and how they worked and how they didn't. These are my disclosures. The only disclosure I have is that I'm a trainee of Ed, and I'm sure I'm mostly floralist, and I know that probably makes him cringe a little bit sometimes when I call for his help. But we'll get through this. And then finally, so when thinking about what case I was going to present, again, title shades of gray, some of you pressured me to make a reference to 50 shades of gray, and we thought we'd be more appropriate for today, and we're painting our house. I spend a lot of time on the Benjamin Moore website, and there are actually 425 shades of gray on this site. So we're going to intentionally pick an obscure one that I think highlights the goals of this session here. So here's our one case. So this is a 14-year-old male, asymptomatic, WPW, 40 kilograms. He came in for his initial evaluation. This is his 12-week ECG in pre-excited sinus rhythm, suggestive of a septal substrate. And this is our first map. As some people mentioned, I still usually start with point-by-point for pathways. This is a point-by-point map that was made with a linear ablation catheter. You can see the very low-density electroanatomic activation we have that pointed us towards the posteroceptal region. And needless to say, this case didn't go well. First thing missing from this map is there's no coronary sinus. We could not cannulate the coronary sinus. Did the usual tricks of getting neck access, trying from above. Tried probing around with wires and shaped catheters and could not get anything in there. Mapped the left posteroceptive with not very competitive time signals. And so we moved on with diagnostics. And so the APERP at rest was 310. The SPRI with atrial pacing was 230. And when we put him into AF, his SPRNF was also sub-250. So we met classical criteria for high-risk conduction. We also put him into AVRT. So we had a lot of reasons to move forward and try to get rid of this. We did some test ablations at our best signals and I say best because they weren't really all that attractive. We got junctional acceleration here. And at this red dot here, we got transient loss of pre-excitation. But when we lost pre-excitation, it would go away for a minute or so and come back. It was first-degree AV block. And while in junctional excel we didn't have any retrograde block, it didn't really feel that good to move forward. We'd just keep blasting this area with non-competitive signals. So pressed pause and did as Ed probably told me to do on that day and start taking pictures. So here on the left is an RAO view and on the right is an LAO view of a selective left coronary angiography. It got cut off. I'm not sure why. But the catheter is in the left coronary. And what you can see here, first on the left panel, is contrast hangs in the CS body a little bit. It's very prominent. You could say dilated even. But it doesn't fill the RA until you see it up by the his bundle catheter region. And you can see that, honestly, in both pictures, but probably equally good on both. So something was fishy about this case, and with the first-degree AV block, I didn't really feel comfortable continuing with ablation without more discussion with the family. So we pressed pause and stopped the case. We got a cardiac CT scan, which was officially read out by the imagers as saying there was coronary osteostenosis versus atresia, but didn't really provide much other details in terms of collateralization or any other drainage to the right atrium. And here, this is a coronal view. And here you can see, if you can see my cursor, this is the middle cardiac vein. This is the coronary sinus here, which I would normally think is where the osteum should be, but it's just a blind-ending structure. And then as you pan inward, you start seeing this structure start to communicate superiorly, which was interesting, to say the least, and fit with our angiogram. So we brought him back about a month or two later. And what do you do when you have a redo? At least what I do is I start pulling out all the tools and toys. And so this is a Zickball showcase. This is a high-density map that was made with a grid-type catheter with a ton of points. To steal her analogy, it pointed us here, which is the zip code, to the posteroceptal region, as expected. But when we put the grid catheter over this region, these are the signals. And I can already hear what Ed's saying, that these are not that great signals. They're atrially dominant. There's no AP potential, as he likes to always tell us. And then we started doing more of our test ablations at the sites that we thought were best, and really with no durable success. So what else can we do here? And so that's what I would say, to stick with Frank's analogy, when things aren't going well, you start pulling out other toys. And so this is one benefit of ICE integration, which is obviously available with this system, but soon to be available with other competitors. And what we started doing is, so on the right panel here, this is the CS body, which is quite dilated, as expected with CS stenosis versus atresia. And we started tagging it on the Cardosound map. These are these pink circles. And we kept, with clockwise rotation, we kept tagging it more and more and more towards the septum. And you can see, fitting with the angiogram, the osteal entrance to the RA was right at the His bundle electrogram, which was very bizarre and obviously not that comforting. This just showcases here the osteal entrance to the right atrium, right near the aortic valve, so quite high. Definitely not a normal CS drainage here. And this is not this patient. This is actually very much a normal patient. But I just wanted to showcase, you know, with difficult CS cannulation, again, you can take a CS picture, you can try neck access, you can try probing with wires. This has been my default, and this is actually incredibly straightforward. Here's a live image. This is a prominent eustachian ridge here. So this is kind of medial CTI right here. And this is the coronary sinus. This works, at least for me, about, you know, 95, probably in all cases except this one case I'm presenting here today. But what ICE did show us here, so we never cannulated, but what ICE did show us here, and it wasn't actually till late in the case when I was getting quite depressed and ready to probably give up, we noticed just with further ICE fanning around this region, this little pouch right here in purple, and that was tagged on the map right here, below where the vein, I'll call it, was draining into the right atrium. And we thought, well, why don't we at least make some effort to put our catheter in that pouch? And we put our catheter in that pouch. I'm pretty sure Ed gave the signal, which is not on the screen, a hell yeah, and said, go for it. And we ablated, and we lost pre-excitation. Note the first degree AV block, which I'll come back to. And this stayed away. It's been, I think he just had his year follow-up, and he's been free of SVT and free of recurrent pre-excitation since then. This was his, like I said, his follow-up ECG showing first degree AV block. And I was ready to say this was iatrogenic from ablation and was willing to accept that, given that he had a normal Winkiebach cycle length, and he had high-risk criteria with inducible SVT. I thought that was a fair trade. But we actually were able to track down an infant ECG on him for a murmur eval, and he already had a first degree AV block as an infant. So there's something weird about this kid's septal inputs into his AV node, probably related to his displaced, you know, typical triangle of coach structures. This is a described entity. So many case reports that talk about coronary sinus stenosis and atresia as it relates to accessory pathways. Interestingly, most of these are in the presence of a persistent LSVC, which this patient did not have. And this is just a figure stolen from Dr. Morrow's study on CCTGA for pacemaker implantation. But if I had to guess, my patient had something of this, is what I'm envisioning, where, I mean, minus the Vena-Marshall connection, but basically his CS comes down, and it drains superiorly and right out at the his bundle region. And so in conclusion, I think, you know, specifically CS anomalies are rare, but relevant septal SVT substrates. I am admittedly biased, but I think ICE provides superior definition for the complex posteroseptal region. And I think, at least with this case, I don't think this case would have been successful without seeing that pouch on ICE. And then Frank might be able to see pouches like that on angiography, but I'm not talented enough to do that. But I also think you still need angiography, mainly to interrogate vasculature. So whether that's an LSVC, a CS diverticula, checking for coronary artery patency after ablation, the things that were already mentioned. So with that, I'll stop. Does anybody have any questions? I know everybody probably wants to get to lunch, so I don't want to, like, hold people up too much. I guess my one question, and I probably would gear it towards Frank and Ed, is who both have trained a ton, a ton of people. What of this are you most concerned with as far as the training that you're doing, and what are you most concerned about? What of this are you most concerned with as far as the training that the trainees go? What sort of somewhat of a prescient look for the future, but how do you make sure that your trainees are sort of getting both arms of both K-pop and classic rock throughout for the future? Well, I think I'm like Ed. One of the things that bothers me most about 3-D mapping sometimes is we have a rep that works with us most, and it takes a while. Every time we get a new rep for our mapping, we have to kind of train them how we do this, because we'll fill the map up, and they'll have you a map in two minutes and say, well, that's the spot. And then you say, show me the electrograms. And I always make them show the electrograms on the screen while we're looking at it, because I don't always trust how it annotates, and I think we teach the fellows the importance of that by having them watch us do that. We're also very dogmatic about doing all of the diagnostic principles. We know this is a pathway. Why are we delivering these PVCs? Because someday you're going to need that, and I think it's really incumbent on us during training to hold on to all those basic principles, the principles of entrainment, all the tricks we do. I thought about your case. I mean, we might do, even though he had ART rather than ORT, we might try to figure out where the atrial connection was. I mean, and that's important for coronary sinus. So I think being dogmatic, being thorough, it's not about, you know, get this patient off the table as fast as you can. I mean, I have great respect for the people I work with on the adult side, but we'll spend time doing things that probably you don't really need to do it for that case, but if you don't do it all the time, then when you do need it, you're not... What is that supposed to mean when I've heard people do this? So, Ed, what do you think? Yeah, I mean, the fellowship boot camp starts off at our program looking at a lot of pathology in the cardiac registry, and I think we have to get it through our heads that these cartoons that we put up on the screen, which are wonderful, I mean, they really have revolutionized how we do this, but it's not reality. And any way that you can make that heart seem more real, whether that's ice or angiography or whatever, it really comes down to the tissue and not the tool that you're using to try to represent the tissue. So I think the way we teach our fellows is starting with pathology, and I have a little heart that I put in our fellows' room. I don't know how many people even bother to look at it now, but it's a normal heart. It's a 3-D map, a 3-D printing of a normal heart from our cardiac registry. And I can't tell you how many hours I spent staring at those things when we first started doing ablation. I think, Frank, you did something very similar. You're not taught the anatomy of the AV groove as part of pediatric cardiology, and you have to learn that on your own. And it's complicated. The coronary sinus is complicated. The tissue along the AV groove, particularly in congenital heart disease, is complicated, as we've discussed here today. So try to get as close to the reality as possible when you decide how you're going to ablate. I think it also ties in, I think, with the open mapping. I like open mapping on the right side because I think if you look at the actual pathology of excessive pathways on the right, even the embryologic anatomy of the tricuspid valve and the microvalve are different, and that impacts your catheter position, it impacts your approach. And right-sided pathways tend to be broader. I do think that open-window mapping may help us, we'll see, with recurrence because I think, you know, how many times you burn, oh, it wasn't doing good, it wasn't good, it wasn't good, it was super exciting, then you finally get it. Well, George Van Hare a long time ago said, you know, I can't remember what he was referring to, but sometimes it takes a lot of successful lesions. And I think open-window mapping may give us some insight about how wide is that conduction gap and how much territory do we need to cover. I don't want to settle for just we got the pathway, but try to cover that entire breakout point. I was just going to say, I think we're probably at a juncture now where we're at risk of speaking two different languages with our senior colleagues and our junior colleagues. And so I know, you know, for example, when I call Ed in for a tough case, you know, he usually, I have the checklist of things he wants, which is an angiogram, and let on, and, you know, you have to start, I want to be able to speak the same language as him and take his advice, which is obviously so critical and helpful. Whereas, you know, by default, I'm usually using ICE, and, you know, it might not be as clear to him when we're speaking about the same things. And then the only other thing I'll say is, the map is a cartoon, as was already mentioned. Flora doesn't lie, I don't think ICE lies either. And so you have to pick something that represents reality. And I'll just say, from putting up ICE in a lot of, pretty much all my redos I use it, Iqbal showed a very nice example of a prominent tricuspid ridge in an otherwise normal heart, you start seeing weird stuff. Prominent ridges, big eustachian valves, very prominent tendon of Totoro's, and it becomes not surprising when you think about that, why there are recurrences. Like you think you're pressing on the map and touching tissue, but there's stuff in the way. And I think ICE can alleviate some of that. Okay, one question. You can all hear me. One question, in retrospect, on your CT, did that little pouch show up? It didn't. You know, that's a good point. It would be interesting to go back with an imager to review that CT with that information, but it wasn't commented on, and again I'm not a good enough cross-sectional imager to point at it there. Yeah, because I wonder if it would have shown up on, we use CartaMerge, and have that overlay, and like, oh, shoot, I need to go to that little pouch. Yeah. My question's for Ted also. Congratulations on the outcome of your case. So other than the pre-excitation pattern on the ECG, I'm curious to know what held you back, and obviously this was the correct call, what held you back from going transeptal and mapping on the left? Oh, sorry, I did. If I didn't mention that, I apologize. I did map the left post-traceptal space in both. Oh, great, okay. Did I say that? Sorry. Did I? Okay, sorry. Yeah. But the signals, we didn't do test ablation, and the signals were late. All right, well, everybody go have lunch, enjoy, and thank you very much for a great session.

accessory pathways

high-density mapping

fluoroscopy

ablation targets

point-by-point mapping

cardiac anatomy

electrophysiological technology

intracardiac echocardiography

cardiac CT

patient safety