me talking. So good morning, everybody. Bright and early. I hope everybody is staying safe in these difficult times. I want to spend some time talking about balloon technologies that you can use during afib ablation. And if you think about it for, these are my disclosures, for EP fellows, currently, it's actually a good time. If you look at this graph, and you look at the number of patients that you will likely encounter in your professional career, well, it's an ever-increasing number. So we're not running out of business. There are more and more afib ablations that need to be done. And therefore, we need new and other technologies to help us to reach that goal. And all of you know that for symptomatic paroxysmal afib, a catheter ablation is indicated in those who are refractory intolerant to at least one antiarrhythmic drug. And at minimum, what you need to do during the procedure is to electrically isolate the pulmonary veins. And the balloon technologies are really created to achieve this goal, to target the pulmonary veins first. And this is what we've been doing for many, many years. This is point-by-point RF ablation. You can see the dotted line around the left side of the pulmonary veins. And you can see that you need to create many, many dots in a contiguous fashion to create a nice contiguous line. So it sounds very simple. However, if you think about it, when you're in the EP lab and you're trying to ablate around the pulmonary veins, oftentimes what will happen is that your catheter will start there, and you try to do a lesion there. And then you jump around. Maybe you end up elsewhere around the circle that you want to create. And at some point, you're able to create a full circle. However, these were not really adjacent lesions. They were kind of created here and there, and then finally formed a circle. That lends to the idea that maybe that can cause more gaps in the long run. While an operator who's very skilled can do adjacent lesions in a contiguous lesion set. And actually, this was looked at in the EPICA studies. These were the first studies that looked at contact force catheters. And you could see and show that for those operators that used adjacent lesions, their outcome after three months when you took all patients back and looked at the pulmonary veins actually had much better outcome in that there was hardly any gap at that time. So what I want to say is that you need a lot of skill to do RF ablation, point-by-point ablation. And creating these circles takes time to really accomplish. I would say you probably need at least 100 AFib ablations until you can comfortably say that any patient that comes along, you're able to isolate every vein. And then if you think about the fact that, when this was from 2015, about the advanced training in EP, if you think about the fact that most procedures are really performed in hospitals that probably don't do more than 100 or maybe even less than 50 procedures, and that each operator probably doesn't do a whole lot of AFib ablations per year, then the question is, how do you really accomplish that skill? What can you do to get better without having to do hundreds of procedures per year to keep your skills up? And this is really where the balloon technologies come in. And I'm only gonna focus on those, on these technologies that are FDA approved. So I'm gonna talk mainly about the laser balloon and the cryo balloon. And to keep in mind, obviously these technologies use different energy forms. RF, we all know, uses energy that kind of disrupts the endothelial layer and then disperses energy and heat into the deeper tissue. Laser also uses heat. However, it's thought to really protect the endothelium and really increase the energy delivery in the deeper tissue. While cryo energy, well, it's cold. So it's basically freezing the tissue. So that's something very different altogether. And these are histology preparations of atrial muscle one weekend. And you can see on the left, RF ablation. You can see disrupted endocardium. You can see that there is thrombus present. You can see the jagged edges where the fibrosis started. It's a very inhomogeneous lesion with some hemorrhage seen as well. And you can compare this to the right upper picture, which is after cryo one weekend. And you can see there's hardly any endothelial disruption. There's just very minimal thrombus present and there's a well demarcated homogeneous fibrotic lesion. And the right lower image shows a laser lesion. And you can see that most of the endothelium is intact, but you do see there's some homogeneous fibrosis within the lesion. So it looks like that this is a much cleaner lesion compared to RF. And this is just an example of how you can imagine a cryo lesion looks compared to an RF lesion, right? So cryo doesn't really change the structure of the tissue, while heat obviously causes, you know, to be like the stake here on the left side, which I would probably prefer. But I think for ablation, it might be a good idea to keep the structure intact. So let's focus first on the laser balloon. Keep in mind, this is a point by point ablation. And probably most of you are not familiar with the laser balloon. It's been around for quite some time. And I just wanna share some details that are important to understand how this technology works. So number one, it's a point by point ablation. That means there is a laser that projects a 30 degree arc onto the tissue. And you do have to move that laser every so often to create a contiguous lesion set. That means you can use anywhere between 5.5 to 12 watts. So we're talking about very different watt setting compared to RF because it's just a different energy form. And the ablation lesion that is created takes anywhere between 20 to 30 seconds. And then after the lesion is complete, you need to make sure that you overlap each lesion by about 30 to 50%. So in total, you need about 24 lesions to get around the pulmonary vein. Now, the really cool feature is that there's a tiny endoscope embedded into the catheter, which allows you to directly see the target tissue. And this is really unique and was quite an eye opener at first when we used this technology, that you're actually inside the left atrium and you're looking at the pulmonary vein while you ablate the pulmonary vein. And I have some images to kind of demonstrate. So, but first let's focus on the lower images here, the flora images. As you can see that the balloon is radio opaque. The balloon is actually flushed and filled with heavy water, deuterium. Why heavy water? Because heavy water does not absorb laser energy. If you were to use normal water, the water would heat up from the laser energy emitted through the water towards the tissue and would absorb too much energy to even create a lesion. So it's filled with heavy water. And you can see that you can increase the balloon size by filling the balloon with more heavy water. And you can see that you will increase the contact between the balloon surface and the tissue. The bigger the balloon becomes, and that really depends on the pulmonary vein that you target. You probably don't need a very large balloon size for smaller veins. But in this case, you can see that the largest diameter here on the right causes very nice contact between tissue and balloon. And how do you know you're in good contact? Because you can see this gray area here that delineates that you have beautiful contact. The black in the back here is blood and this kind of blackish area here is the pulmonary vein that you're looking at and the blood that's pushed back into the pulmonary vein by the balloon. And this is a typical image that we see. And just to orient you again, we're looking at the left-sided vein. So imagine yourself standing within the left atrium and you're looking at the left superior and left inferior pulmonary vein. You would imagine that the left atrial appendage would be somewhere here. You can't see it. You see the left superior pulmonary vein and you can actually see a little bit of a lasso catheter inside the left superior pulmonary vein. You'd see the left inferior pulmonary vein. You can see the carina and the posterior part and the anterior ridge of the veins. And you also appreciate that there is some type of a blind spot right here. This is the shaft of the laser balloon catheter that you can't really visualize the tissue behind. So you have a 270 degree view, but you're kind of leaving out this blind spot. So at some point, you may have to rotate the catheter to complete your lesion line here. And this is the laser light that emits a pulsating light when you're just looking. And you can see that this is right at the side of the blind spot inferiorly. And what you need to do now is complete the lesion set. And again, similar picture here, left superior pulmonary vein, left inferior pulmonary vein, this is the posterior wall. You can see the laser light right here, a little bit of bubbles within the balloon. So don't worry about those. And just follow the laser light in this video. You can see, obviously I sped this up a little bit, but you can see how the laser light is one lesion after another. And then you kind of move on, go down the anterior ridge. Then you cross the carina right here, turn the laser balloon around again. And so that's how you complete a complete, nice circular lesion set around the individual veins. Keep in mind that you isolate each vein individually. So once you're done with left superior pulmonary vein, you would put the balloon into left inferior pulmonary vein, and you would also cross the carina again. Now, there was a randomized prospective trial comparing the laser balloon with the Biosense Webster Thermocool Catheter and a CARDO mapping system. And this was a trial to allow the laser balloon to be used here in the United States. 366 patients were treated. And the endpoint was a freedom from a FIP greater than one minute after the blanking period over a 12-month follow-up. And you can see that there was equivalence and outcome. So this was a non-inferiority trial, meaning that the success rate was identical between, or less identical between these two technologies, but the laser balloon was not better. The trial was not set out to test superiority. And this led to FDA approval of the laser balloon in the United States. Now, there's some five-year follow-up from Europe, just to kind of share this with you. So after multiple procedures, 78% success rate in these patients. But more importantly, there's some interesting developments in regards to this balloon. I showed you earlier an image where you can see how the balloon is filled with heavy water. And you can see the more you fill it, the kind of rounder it becomes. And the old balloon is not that conformant to the tissue. While you can see the new balloon called Excalibur that's being used on the United States, it's much more conformable to the tissue. And hence, you'll be able to really get into a nice position for any vein that you encounter. And it also allows you to be more antral, to allow more antral position. To really make you understand what the difference here is, just look at these videos. So this is the old balloon, and you're trying to push against the pulmonary vein. And you can see with every contraction, the balloon loses tissue contact with the left atrial wall right here. And it takes some finesse to really get it into a position where this pulsation does not inhibit your view. While with the new balloon, same patient, same vein, you can see despite the contraction, the balloon nicely conforms to the tissue. And hence, you have a beautiful 270 degree view and you can do a very nice ablation around this vein. So this is an example of a arrhythmia map before laser balloon ablation in a patient with paroxysmal atrial fibrillation. This is a voltage map, so the purple is normal voltage. You can see basically that the left atrium shows, demonstrates normal voltage. And this is the post-map after laser balloon ablation. And you can see very nice the delineation of the area of isolation around the left-sided and the right-sided veins. And in regards to how quickly you can learn this technology, that's important because I told you RF ablation is quite difficult to learn. This is a study also from Germany with operators that were new to the laser balloon technology but were very experienced in RF and cryo balloon ablation. And you can see it took about 10 to 15 procedures for these operators to get down to the laser balloon. So you get down to a average procedure time or of like 132 minutes. And then with every other 15 patient cohort, you can see that number of procedure, that the procedure time decreased further. So you can probably complete a procedure within like 90 minutes. You can see sometimes there's an outlier and it takes a little longer, but usually it takes about 90 minutes to complete. Now this is with the old balloon plus the new balloon, but there's another exciting technology now that they embedded into their balloon catheter. And that's something called HeartLight X3, meaning it's a rapid automated mode to ablate. And I have an image of that in my next slide, but just kind of look at this beautiful contiguous lesion that is just perfectly placed around this slab of meat. So let's look at this. So this is a video I took in Germany when my colleagues, Dr. Rillig and Reisman did a case in Hamburg. And just to orange you, again, this is the blind spot here. You look right into the pulmonary vein. The black is the blood that's pushed back by the balloon. You have beautiful contact with the surface around the vein. And you can see the laser actually pulsating here. So they're ablating right now. And you can see if you look closely that that laser light is moving ever just in a continuous fashion, very slowly, but is ablating while it's moving. And hence you can complete a lesion in about three minutes around each vein. So this is a really speedy way of ablating. You need to have a very nice view initially, but then you can automate this and it makes your life much easier. And you can probably complete procedures within 60 to 90 minutes. This will hopefully come to the United States by May. And then we can try this out. Okay, let's talk about the CryBalloon. So the CryBalloon is really a true single-shot technology. That means you apply energy and it causes an instant circumferential lesion. And obviously depending on the duration, this will be hopefully a persistent transformer lesion. Eric, can I interrupt you? So maybe that's a good time, maybe ask some questions. Sure. I have a couple of questions. If it's capable of what it's shown to do, do you really need to go across the carina? And then why do you go across it twice? Can't you make just a big circle around both veins? And the second question is, can you see the lesions as you deliver them? I didn't see any change in the tissue appearance as that laser light was moving around. Yeah, let me answer your second question. So do you actually see the lesion that you create? And in a porcelain model, because the color of the muscle is really pink, you can easily see it. However, in a human, you may just see a little bit of what we call edema formation. So not really reliable, the lesion that you create. So unfortunately so far, we have not a good way of establishing whether the lesion that you just created and when you move on is actually a true good lesion. So you have to rely on the time you spent there and that you didn't move and that you have nice overlap. In regards to your first question, why not just do a wide circumferential lesion set around the left and right-sided veins? Well, we actually tried this and we published this a while back with the old generation balloon. For the left-sided pulmonary veins, it probably would make sense to do that because what you really need to do is in order to connect your lesion sets, you need to be able to see both veins at the same time. And that's oftentimes a problem for the right-sided veins because anatomically they're further apart from each other. So if you take your balloon and put it into the right superior pulmonary vein, you may not be able to see the right inferior pulmonary vein. So that means if you do a half circle around the right superior pulmonary vein and then put your balloon into the right inferior pulmonary vein to complete a wide circumferential lesion set around both veins, you do not know where to connect these two half circles because you can't see the ipsilateral vein. Now, interestingly, with the new balloon, the Excalibur, as I showed you, the maximum diameter you can have is 38 millimeters. So it's very large. And typically you can see the ipsilateral vein and you could probably connect. So I don't think anybody has done the study on the new balloon. Would be interesting to see, and I think a nice study to hear about. So historically, we've just kind of come to the, we learned that you probably need to isolate each vein individually. Now, could you skip the carina the second time around? Probably you could. However, especially for the left-sided veins, the really important region where oftentimes you may encounter difficulty isolating the vein is right at the anterior ridge at the transition into the carina. That's where the tissue is exceptionally thick and you may need more ablations. And that's why we typically just continue to go around the carina twice. Eric, we had a few other kind of process questions for laser. One was, how do you map gaps with the balloon? How do you make sure you're antral enough? And do you have to monitor phrenic? Okay, how do you know you're antral enough? Well, you actually do see where you are. Number one, you can see on fluoro where you are. Number two, you can see how deep inside the pulmonary veins you are. Imagine the left superior pulmonary vein. The further you're outside of the vein, the more you will see of the left inferior pulmonary vein. And in that regard, you can kind of judge how far in or out you are. The phrenic nerve is very important. Similar to cryo-balloon ablation, you do need to stimulate the phrenic nerve when you ablate around the right side of pulmonary veins. And I use this, the identical maneuver I use also for the cryo-balloon called C-MAP, the compound motor action potential, where I stimulate the phrenic nerve within the superior vena cava and look at the contraction and also measure the amplitude that is created by putting two leads over the diaphragm on the right and make sure that I don't do any harm. So for both balloon technologies, the phrenic nerve needs to be protected. And for your last, or the last question was, how do you make sure that there are no gaps left behind? And if you have a gap, how do you map? So the best way about this is to make sure you have a beautiful 270-degree view right at the beginning before you start the first ablation. That makes your life so much easier because all you need to do is make sure that you overlap and you can see that. You have a review screen also that always shows you the last lesion that you created. So you always can make sure that you see basically both lesions overlapping. And if you do that, then the chance of isolating with one go-around is about 80 to 90%. Now, in those cases where you have a gap, you can either put a lesser catheter into the vein and then according to the electrodes that show the earliest connection, you can target that area again. So typically what I do is if I put a lasso into the left superior pulmonary vein and there is a gap anterior superior, I'll take the lasso out, put the balloon back in, and then just focus on ablating again, maybe a quarter of a circle at the anterior superior aspect and then recheck with my lasso. Sometimes you can also leave the lasso catheter within the vein and put the balloon into the vein and kind of push towards the lasso that you can do if it becomes really difficult, but it's oftentimes not needed. Okay, shall I move on? So the cryo-balloon. So the cryo-balloon, and I'm pretty sure that most of you are familiar with the cryo-balloon technology, again, it's a single-shot technology. It's fairly simple, so I can actually demonstrate in four steps how to do it. After transversal puncture, the inflated balloon is inserted into the left atrium. You use a over-the-wire technique using the achieve catheter that is placed through the lumen of the cryo-balloon into the target vein. Once you're there, you can inflate the balloon and then push with the balloon against the pulmonary vein as to achieve complete sealing. The sealing is confirmed by injecting contrast through the distal port of the balloon or pacifying the pulmonary vein without any backwash into left atrium, signifying that you have perfect occlusion, and then you push a button and then you ablate. The nice thing about the cryo-balloon is that once you start freezing about 30 seconds into the freeze, you are stuck to tissue, so the catheter typically doesn't dislodge. That's oftentimes, as you know, a problem with RF ablation that a catheter can easily dislodge. Once the cryo-balloon is frozen to tissue, it does not dislodge. And during the freeze, what happens? Well, first there's extracellular ice formation, and then that's followed by intracellular ice formation. But keep in mind that there is also a period called the thawing period that is very important to cause a persistent transmural lesion and even furthers the necrosis and apoptosis. This is the time when you stop with the active freeze. The balloon is still stuck to the tissue and rewarms until it reaches 20 degrees Celsius and then automatically deflates. So the longer the period, the thawing period, the better quality of a lesion you have, and there's actually some evidence that the thawing period correlates with the success rate over time. And these are just some examples, so how powerful this balloon can be. This is, on the left, you can, if you have not tried this in your fellowship, please do. Start freezing the balloon outside of the patient, maybe in a water basin, and then you can see at some point how powerful the freeze and how much ice is formed around the balloon. And on the right image, this is a case report doing a videoscopy within the epicardial space and the cryo-balloon targeting the left pulmonary veins. You can see that the ice formation actually goes beyond the epicardial layer of the left atrium and you can see how powerful it is and how you can actually freeze tissue that may not be your target tissue if you're not careful. And the largest trial to date is for any type of ablation technology, is the fire and ice trial. This was a randomized prospective trial comparing the cryo-balloon, at that time, the Arctic front catheter and the Arctic front advance, so the first and second generation balloons with RF ablation. And again, this was with the biosense, what's the family of catheters? The thermocooled catheters, which could be at that point, the normal thermocooled catheters, but also was extended to use the contact force catheters and a cardio three mapping system. And the combined primary endpoint was either recurrence of any type of AFib, atrial tachycardia, a flutter more than 30 seconds, or a prescription of antiarrhythmic drugs, or the patient needed a reablation attempt over one year. And the outcome was more or less identical. So this was a non-inferiority trial. And you could say that the cryo-balloon was as good as RF ablation, certainly not better. The trial was not big enough to show that. And you can see at the bottom that over one year, most of these patients, if they had a recurrence, it was due to an atrial arrhythmia. Now, there were some subgroup analysis that I just want to kind of go over really quickly. Over a thousand day or like three year follow-up, it could be seen that those patients who were treated with the cryo-balloon and these were all patients with paroxysmal atrial fibrillation, had fewer re-hospitalizations due to cardiovascular problems. And this could be either for a recurrent AFib or any other type of heart issue. And you can also see that patients in the cryo-balloon group had fewer repeat ablations over these thousand days of follow-up. And both of these decreases in CV re-hospitalization rates and repeat ablations may have an effect on the health economics. And this was a nice study that was published in the Journal of American Heart Association. It's like an online journal by Yankee Chun. And actually for countries like Germany, United Kingdom and United States, they estimated the costs for patients that needed to come in either for cardioversion, for non-cardiovascular rehospitalization, for cardiovascular rehospitalizations or for repeat ablations. And you could see that because the cryo-Bluen had less lower rate for either, that you could save about, for the United States, $925 per patient. Doesn't sound very much for one patient, but if you were to say we have 75,000 fill ablations per year, and you were to do all this with the cryo-Bluen, you could save a larger number, larger amount of money. So something to keep in mind. Now, interestingly, let's talk a little bit more about reablation. So in the fire and ice trial, really the graph separated quite late, probably beyond 400 days until this became more prominent that the cryo-Bluen had less reablation. But there's a registry that asked for European patients to placed in, this is a corporation by the European Society of Cardiology and the European Heart Rhythm Association. And they used their registry data in patients with paroxysmal atrial fibrillation and combined it with the Swedish registry. Basically all patients in Sweden that undergo cryo-Bluen ablation for paroxysmal atrial fibrillation were put in there. And you can see that in those registries, the separation of graphs appeared much earlier, about 100 days, you could see actually a clear separation between the cryo-Bluen patients and the RF patients, and that the cryo-Bluen patients had a lower rate of reablation and better survival. So now when you compare RF and the cryo-Bluen, this was a study published in 2016 by Arash Aryana, you can see that also the PV reconnection rates is different. So not only do you have lesser ablations after the index ablation, but you also, when you take patients back with a recurrence and you compare those patients that came back after an initial RF ablation versus cryo-Bluen ablation, those patients who had the cryo-Bluen ablation had lesser reconnected pulmonary veins during the repeat ablation. And this was another study from 2016 from the Russell's group. And here they're compared the second generation cryo-Bluen with a thermocool smart touch catheter. So one of the catheters that we typically use for RF-PVI. And again, you could see that the reconnection rate, which was much higher for RF ablated patients doing the first, after the first or the index procedure. And especially when they took patients back, the gaps were around the colina. Now, just very recently, there was another sub-study from the Fire and Ice trial. And what they looked at is those patients. And we saw that in an earlier slide. In the RF group, there were 66 patients who underwent a redo ablation for recurrence. In the cryo-Bluen group, there were 44 patients that underwent a redo ablation. 53 and 36 of each group was, there was not enough data to really collect enough information to come up with the data that was presented in the study. So they had 53 patients in the RF group that underwent a second procedure and the operators were encouraged to use the same technology. So all 53 patients underwent a second RF redo-PVI procedure. And interestingly for the cryo-Bluen patients, the 36 patients, only a third underwent a second cryo-Bluen procedure. Most of the operators elected to do a redo RF-PVI procedure. And this is outcome that's fairly similar to what I showed you earlier, that in those patients who had the initial procedure done with the cryo-Bluen, they had less PV reconnections. And I think really important to see here is when you look at the number of veins that were reconnected, actually a quarter of patients that had an RF-PVI ablation as the index ablation, a quarter of these patients had all pulmonary veins reconnected. How frustrating is that? So you have a patient come back for a redo procedure and all veins are reconnected. A lot of work you have to do. Well, for the cryo-Bluen, that was really quite rare. And when you look at the individual veins, you can see there was a significant difference for the left superior pulmonary vein. So the left superior pulmonary vein was statistically with fewer reconnections compared to the RF group. And there was a tendency of a lower rate for the left inferior pulmonary vein and the right superior pulmonary vein. And when you look at the number of studies that compared RF in yellow with the second generation cryo-Bluen in orange, you can see that all these studies showed a lower reconnection rate for the cryo-Bluen. Now, let's talk a little bit about the ablation protocol that we use. Remember when you're in the lab and you do a cryo-Bluen procedure, depending on the attending that you work with, everybody has their own little spiel of how to do things. And initially when the second generation cryo-Bluen in the optic front advance came out, we were told to ablate 240 seconds times two, meaning you did a nice ablation to isolate left superior pulmonary vein, but then you had to do a bonus freeze for each vein to make sure that you have a good transmural lesion set. Now, in a study that we published really a while back, we showed that the bonus freeze is really not necessary. So all you need to do is do a freeze for 240 seconds if the vein isolates, that should be enough compared to a group with the bonus freeze and the outcome was identical over one year. So that led to the idea of just doing one freeze per vein, which really can speed up the whole procedure. Then you can see that the group in Brussels published a paper of a three minute freeze, so 180 seconds, that should be enough. So even faster, so we're kind of racing for the fastest procedure. So 180 second freeze probably should be enough. But then remember the cryo balloon allows the achieve catheter, which is similar to elastocatheter from Biosense Webster, and that you can nicely place it in the pulmonary vein and you can actually look at the PV signals and then see the PV signals disappear during your freeze to confirm life that you isolated the vein. This was the time to isolation that can be measured. And the idea was once you can see it and the faster you can do that, probably the better the freeze overall freeze quality is. And there were at least two studies that looked at time to isolation. There are more studies, I'm just mentioning two here. This was a study here in the United States that was performed with a time to effect protocol, how to kind of individualize the ablation therapy for each of your patients. And then there was a time to isolation protocol called IST from the Frankfurt Group in Germany that I wanna go into a little bit more because they just had a follow-up study on this protocol that's very interesting. So just for you to understand what they did is the following. They targeted each vein, and if they saw the PV signal disappear so that the vein isolate within 75 seconds, all they did was a single freeze, no bonus freeze. If they saw time to isolation between 75 to 90 seconds, they gave a bonus freeze. If they did not see time to isolation so the vein was not isolating within 90 seconds, they aborted the freeze and kind of put the catheter in a slightly different position and try it again. Now they published the data, but more importantly, they now did a follow-up study that was just recently published in Jackie P. And I just wanna guide you through the slide. It's a pretty busy slide, but very interesting. So what they did is they followed the same protocol that I just explained to you, but for the freeze duration, they either used 240 seconds or 180 seconds. Now, when you ask operators what's the freeze duration they use right now, it's probably either three minutes or four minutes. I typically use 180 seconds for my freeze duration. But you can see that there was a significant difference between gaps that formed after the ablation. So they had in total 604 patients that underwent this type of time to isolation protocol using a 240 second freeze, and 184 patients who were treated with the 180 second freeze. And then they had those patients who had a recurrence come back to the lab. They put a lasso catheter into the vein and they looked for gaps. And you can see that the number of gaps was much higher for the group that had an 180 second freeze compared to the group with the 240 second freeze. And particularly around the left-sided veins, there was a much higher rate of reconnections, and especially around the anterior ridge. So let's think about this, because what is anatomically different around this area, the anterior ridge that may make the 180 second freeze less optimal? And maybe you should prefer a 240 second freeze. Well, let's look at some data that was created to compare the Arctic Front Advanced, that's the second generation cryo-balloon that we've been talking about, to the newest generation, the Arctic Front Advanced Pro. You can see that the footprint, really the freeze pattern looks fairly identical. I'll get to some differences here in a moment, but just stay with me here for this slide. So this is a computational model that compares the older second generation balloon with the newest, which is the fourth generation cryo-balloon. And what was done in this study is to look at the time it takes for electrical dormancy to occur. Electrical dormancy is equal to the time to isolation. When does the pulmonary vein signal disappear? Typically, the temperature around that time, electrical dormancy, occurs at plus 23 degrees Celsius. And only once you get to minus 20 degrees Celsius, do you have non-viable tissue. That would be the perfect transmoral lesion. Now for the second generation balloon, just focus on a lesion that was created with a tissue depth of three millimeters. If you think about the left atrium, typically, if you ask someone, they would tell you, well, the tissue depth is probably two to three millimeters. So when you do a lesion with a tissue thickness of three millimeters, it takes about 60 seconds for time to isolation, for electrical dormancy to occur. And it takes about 161 seconds for a transmoral lesion to occur. And this was more or less identical for the newest generation balloon because the freeze pattern is identical. Okay, so far so good. Now think about the anterior ridge. What's so special about the anterior ridge? Well, that's really the separation between the left side of pulmonary veins and the left atrial appendage. And that tissue can be quite thick. And I would argue probably the tissue may be thicker than three millimeters, maybe let's say four millimeters. Now look at this computational model. And when you have four millimeter of tissue thickness, it takes about 80 seconds to see time to isolation. And it may take up to 350 seconds for a complete transmoral lesion to occur. And this may explain why the Frankfurt Group saw a high number of reconnected veins with 180 second freeze, because if the tissue, especially along the anterior ridge is so thick, a 240 second freeze probably will be much more successful than 180 second freeze. So maybe we have to reconsider our ablation strategy and also not only consider time to isolation, but also the possible thickness of the tissue that you target. Now, really the reason why Medtronic came out with the newest generation balloon, the Arctic Front Advanced Pro, is to decrease the nose of the balloon. So instead of 13.5 millimeter, it's now eight millimeters in length. And the reason for that is really to allow you to pull back the achieved catheter closer to the surface of the distal balloon hemisphere, and to allow you to get a more actual position within the pulmonary vein to allow for a higher rate of PV signal registration. So in other words, if you have a longer nose, your achieved catheter may be very distal in the pulmonary vein, and you may not see any signals. If you don't see any PV signals and you're freeze, you will never be able to tell if the vein isolated during that freeze. You can only check afterwards. So to increase the rate of PV signal registration, the shorter nose might be preferred. And this was a study that was just published online a couple of weeks ago, again, from the Hamburg group in Germany that looked at the second generation and the newest generation cryo-balloon. So in light blue, that's the newest generation cryo-balloon. In dark blue, that's the second generation cryo-balloon. And you can see that there was a trend of a higher rate of PV signal registration for each vein. And when you look at the procedural data, I don't wanna go into detail. Actually, what I wanna show you is that the operators were able to complete a cryo-balloon procedure anywhere between 65 to like 83 minutes per patient, which is quite speedy and probably allows for more procedures to be done per day and more patients to be treated over time. Okay. So what are the take-home points here? Well, for one, for patients with paroxysmal atrial fibrillation, I think the balloon technologies are really a viable option besides RF ablation. I do think, especially for EP fellows, fresh out of fellowship, being new attendings, this might be a good strategy to be successful because it's easier to learn a balloon technology and you may only have a day per week in the lab. And so you probably won't be able to really do a thousand RF procedures to be really good at it. So maybe a balloon technology is preferable. And your lab will love you because a balloon technology typically means that the patient is treated faster and the procedures are also more predictable, meaning typically they're done within that certain timeframe, anywhere between 60 to 90 minutes. So something to keep in mind for you who might venture out soon to be attending. So with that, I wanna complete. Pretty sure there's some questions that I'm happy to answer. Yeah. Thanks, Eric. There are a couple of questions. One's just kind of a process question on strategies for isolating a difficult right inferior vein, both with the laser balloon and the cryo. And then if there are less PV reconnections, why do you think cryo was non-inferior to RF and fire and ice? So in regards to the first question, so the right inferior pulmonary vein is historically the vein that's most difficult for balloon technologies. Why could that be? Well, if you think about the transeptal puncture and the proximity of the transeptal puncture to the right inferior pulmonary vein, oftentimes there's not much room. Balloon has a certain size. So you probably wanna select a transeptal puncture site that might be a little bit more interior than what you're used to for RF ablation. For the newest laser balloon, the Excalibur, in my opinion, in my experience, it's much easier now to isolate the right inferior pulmonary vein. And that's because the balloon conforms so nicely to the vein, and it's very easy to see a full circumferential view of the right inferior pulmonary vein. So actually, since I've been using the new balloon, I have not had any difficulties isolating the right inferior pulmonary vein. Now for the cryo balloon, it's fairly similar. The right inferior pulmonary vein is probably the most difficult to ablate. So one thing that I like to do that's typically not supported by Medtronic is called a pull-down maneuver. So first I try to place the balloon right in front of the right inferior pulmonary vein. And I typically use contrast that I inject to make sure I put sealing. Now, if I don't achieve that with first positioning, oftentimes what I do is I try to seal the superior part of the right inferior pulmonary vein. There's a leak inferiorly when I give contrast. And I accept that leak for now. I start freezing, and after 60 seconds, when the balloon is frozen to the superior portion of the right inferior pulmonary vein, I pull balloon and sheath back a little bit. And with that, I complete sealing of the inferior border. So you have seating a little later around the inferior border of the right inferior pulmonary vein, but oftentimes that works for tricky veins. The other thing that you wanna make sure is that you check in two angulations on fluoroscopy that your sheath aligns nicely with the cryo-balloons. Because sometimes when you have difficulties achieving good sealing, it may be that your balloon is pushing in a different direction than your sheath. Okay, Nishant, the other question was, sorry, I forgot. It was why do you think fire and ice is non-inferior, though with cryo-balloon, you're getting less reconnection than with RF? Yeah, so yeah, it's a great question. So number one, it was not a superiority trial. So you probably need to do a lot, lot more patience to really show superiority. Two, these were very experienced operators in the trial, which is, I think, in favor for RF ablation. And this favor for cryo-balloon ablation. So if you were to do a trial with new operators to either technique, I would tell you that the cryo-balloon would do much better. And what I thought was very good about the trial, because that's always the criticism for any randomized trial. Well, they use technology that's old. I don't use that anymore. They have newer balloons, newer technologies. That trial was actually in the design very smart in that it would allow new technologies to be embedded. So for RF ablation, at the end of the trial, we could actually use the contact force catheter. But you would think the contact force catheter would really make everything better. But remember, at the time when that trial was done, in 2012, 13, 14, 15, we actually did not know how to use a contact force catheter. Sure, we knew enough contact is needed, but we did only learn later that it still needs adjacent lesions, low continuity index, minimal jumping from one place to another to really complete a good lesion set and have a persistent transfer lesion. So overall, I do think that for the general EP, the CryoBalloon still might be a little bit more successful than using RF. And then keep in mind that we're talking about paroxysmal atrial fibrillation. So there are a lot of patients that need additional lesions and may require, you know, CAFE ablation, linear lesions, and then RF is oftentimes certainly superior, which leads me to one thing that I want to add onto. What do I do if I have a redo case? So a patient that comes back with a FIP after an initial CryoBalloon ablation, I typically use RF. Why do I use RF? Because I know that the gaps, there are probably just a few, maybe one gap. I can easily close that with the RF catheter, but then that might be some extra pulmonary trigger for a FIP that I can only target using an RF catheter. One other question that was asked here, do you have any experience isolating the posterior wall with CryoBalloon? And how do you see balloon technologies fitting in as pulse field ablation takes off in the next five years? So the posterior wall, the structure that I'm most concerned about is the esophagus. And I did not mention, but for both balloon technologies, I would strongly recommend using an esophageal temperature probe so that you have an idea of what temperature is created within the esophagus. Since I worry about the esophagus, I'm quite hesitant to say, oh, by all means, ablate the posterior wall if you think it's so important to the generation and maintenance of atrial fibrillation, because you inadvertently will get closer to the esophagus, which we typically try to avoid. And, you know, when is this necessary? Probably in patients with persistent AFib. And when you think about the STAR-F trials and looking at different lesions you can create in addition to PVI, nothing really has shown to be of benefit. So yes, there are probably some studies out there saying the posterior wall definitely needs to be ablated. Was this in a randomized prospective fashion? Probably not. And hence I'd be rather careful. And hence I'd be rather careful. Can you do it? Of course. But when you do that, you have to be very careful not to injure the esophagus. Now with pulse field ablation, we're all very excited about this. This is something completely new. For those of you who have not heard about it, it's basically an energy form that selectively targets the myocardial tissue. And supposedly does not cause any damage to any nearby tissue that's not cardiac tissue. In other words, you can do a pulmonary vein isolation very, very quickly within seconds without causing any harm to any surrounding tissue besides the pulmonary vein tissue. So that is really probably a game changer. It still needs some time to be available to us. So I would think over the next few years, we'll see more advancements in that regard. Will it surplanned or overcome or replaced balloon technologies? Not for now, but I do think there's a bright future for that technology, but it's gonna take some time. I guess just a couple other questions that have popped up. One is risk of esophageal injury with the laser balloon. And do you get pre-procedure imaging prior to using these technologies for pulmonary vein anatomy in all patients? So a lot of us use either MRI or CT for pulmonary vein. And we're not really sure a lot of us use either MRI or CT for imaging before patients go for an infibrillation. We looked at this. Is it necessary to do an MRI? Is it necessary to do CT for laser balloon or cryo balloon ablation? Because you need to know the anatomy beforehand. Otherwise, maybe some patients could be done. Honestly, we didn't see a difference, meaning whatever comes your way, you can probably target with either balloon technology. So I personally do not do routine pre-procedural imaging unless I wanna get a better idea about the extent of fibrosis, maybe if you believe in that, or there are some other reasons why to do it. So you can, but you don't have to. And Nishant, the other question, sorry. It was, do you have to titrate the energy on the posterior wall to reduce risk of a substantial injury for laser? Yeah, so that's a great question. So for the laser balloon, just to go a little bit more into detail. So what we do is we use a temperature probe. I like the circle probe. The circle probe is kind of like a spiral. Once you remove the stylet from it, it has, I think, 10 or 12 electrodes that can measure the temperature. So basically it stays in place during the whole procedure. You don't have to adjust it to the level of ablation because you have the whole vertical length of the left atrium covered. So once you get to the posterior wall, the laser balloon energy needs to be decreased. So the maximum is currently 12 watts. You would not use that posteriorly. Typically I use anywhere between 10 or eight and a half watts. You want to stop ablation if the temperature rises above 38.5 or 39 degrees Celsius. Historically we used 38 and a half. I typically use 39 degrees Celsius. I have not seen any atrial surfacal fistula, but the laser balloon technology is fairly new and not as many patients have been treated with this technology when you compare it to cryo or RF. But you certainly want to be more careful and use a lesser energy and come off immediately if the temperature goes up. I do give proton pump inhibitors after the procedure. It's the evidence out there that this really makes sense. Well, that's arguable, but I do think that the gastric acid secretion is probably of no help right after the ablation. So I give a proton pump inhibitors for six weeks. Yeah.

balloon technologies

AFib ablation procedures

pulmonary veins isolation

laser balloon

cryo balloon

heat-based ablation

cold-based ablation

Fire and Ice trial

RF ablation