Welcome to the 2021 Quality Summit. Thank you for sharing your time with us today. I have the distinct honor to introduce our speaker for Exploring the AFib Ablation Procedure, Dr. Karamadi. After medical school, Dr. Karamadi completed his intern and residency in medicine at Yale New Haven Hospital in New Haven, Connecticut. He also was serving as an associate research assistant at the time. He then followed his passion for cardiology by completing his cardiology and cardiac electrophysiology fellowships at Johns Hopkins University Hospital in Baltimore, Maryland. He currently is an electrophysiologist at Lincoln L Medical Center in Pennsylvania and contributes to research and education with an impressive list of publications, abstracts, editorials, reviews, and chapters. Dr. Karamadi is generous to share his clinical expertise and guidance with us at the ACC by participating as a member on the EP Registry Suite Steering Committee. The committee serves both the AFib Ablation Registry and the EP Device Implant Registry. Welcome Dr. Karamadi and thank you again for being with us today. Thank you, Christina, for the nice introduction. Let's get started. So I was tasked to explain the technical aspect of AFib ablation, but I think we should start with the past until I need to tell you how we got there. That's what we do now today. So I don't have any financial disclosure. So AFib ablation, AFib surgical or invasive treatment of AFib management started in operating rooms. Cox, Dr. Cox and his colleagues reported the first surgical strategy for management of atrial fibrillation in 1987. And the surgery involved the creation of multiple surgical incisions in the left and right atrium during an open heart surgery. And the goal was to compartmentalize the atrium. Cox MACE procedure went through a few iterations and it is true cut and sew. It means you have to open up the atrium, cut it in different pieces and then sew it back together. And as you see, it was quite a complex procedure involving multiple procedures you see on the right hand screen, different iterations. And now we are on MACE 3 and MACE 4. And the lines are the incisions that surgeons have to create to be a true Cox MACE procedure. There are some long-term follow-up results from patients with Cox MACE procedure and long-term follow-up of 198 patients with paroxysmal or persistent AFib who had the Cox MACE 3 procedure. And 5% of them were AFib-free after 5.3 years of follow-up. However, as you can imagine, it's quite a morbid procedure. The major complication occurred in 12% of patients, including two preoperative deaths. So then electrophysiologists tried to imitate the Cox MACE procedure in electrophysiology labs. In 1994, Hazegar and his colleagues from Bordeaux Group showed the feasibility of cataract ablation as a treatment of atrial fibrillation. And that involved creation of three linear lesions in the right atrium. You can see on the right-hand image that all the lesions were in the right atrium, and there were three of them. And then in 1995, Dr. Schwartz performed linear ablations in the right and left atrium for treatment of atrial fibrillation. In 1997, Pierre J. again from Bordeaux Group showed atrial fibrillation is associated with runs of atrial tachycardia. And he moved on and characterized these atrial tachycardia and localized them to near sinus node, CS ostium, right pulmonary veins, left superior pulmonary veins, and all atrial erythema were successfully treated with RF applications. And in landmark study in 1998, again, Hazegar from Bordeaux Group showed a majority of triggers for atrial fibrillation start in pulmonary veins, and they can be successfully ablated using cataract ablation. So these two images on the lower part of the screen is from that study. And you see the dots are the triggers that they identified, and the majority of these triggers were inside the pulmonary veins. These four dots that you see there in the left atrium and right atrium, they had a few triggers. And the next image next to it, these are intracardiac recordings during the study, and it clearly shows there's a pulmonary vein triggers that initiates atrial fibrillation in the right upper pulmonary vein, right inferior pulmonary vein. And the same is true for another vein. So this is beginning of our understanding that the veins, pulmonary veins are critical in initiation of atrial fibrillation. Then Papone in 2000 started the idea of pulmonary vein isolation as a procedure. So 28 patients with paroxysmal atrial fibrillation were enrolled in that study. They used a mapping system, 3D mapping system, to create a shell of left atrium. And essentially they delivered RF applications around the pulmonary veins and isolated all four pulmonary veins. And in this study, they showed it as feasible with good success rate, 85% of patients were AFib-free, including 62% patients were off enterorythmics and 20% of them were on enterorythmics. And this is the beginning of the pulmonary vein isolation era in 2000. So then there are many studies looking at the efficacy of the catheter ablations and compared to enterorythmics. I put two studies here just for an example. Study one, 70 patients with symptomatic AFib randomized to PVI versus enterorythmics. And they followed the patients for a year. And the primary endpoint was any symptomatic atrial fibrillation or asymptomatic AFib greater than 15 seconds during Holter and event monitorings. And as you see, the pulmonary vein isolation and catheter ablation was superior to enterorythmics in suppression of atrial fibrillation. The study at the bottom is from 2021, so pretty new, 300 patients with symptomatic paroxysmal atrial fibrillation randomized to PVI versus enterorythmics. And all patients had implantable loop recorders and they follow up for a year. And the primary endpoint was first documented recurrence of AFib or atrial tachycardia. And as you see here, ablation is the blue line, enterorythmic is the red line, and ablation was significantly better in suppression of atrial fibrillation compared to enterorythmics. We know catheter ablation is a very effective way in management of atrial fibrillation, but does it affect the mortality? That's really the answer that there are many studies looking at this. The major one was, the first one was a CASLAF study. They enrolled around 400 patients with heart failure, reduced ejection fraction, reduced of taxisomal or persistent AFib, who failed medical therapy or had side effects or they were unwilling to take enterorythmics, and they randomized the patients to catheter ablation versus medical therapy. And the primary endpoints were death or hospitalization for heart failure. And again, catheter ablation is in blue. Medical therapy is in red. And you see the catheter ablation was associated with a significantly lower rate of composite point-of-all-cause mortality or hospitalization for heart failure than medical therapy. So at least for this group of patients, heart failure with reduced ejection fraction who has taxisomal atrial fibrillation, and there are some inclusion and exclusion criteria that's relevant, catheter ablation was associated with a lower mortality. How about general population? And Cabana study attempted to look at this. They enrolled 2,200 patients with symptomatic AFib, and they randomized the patient to catheter ablation or medical therapy. And the primary endpoint was death, disabling stroke, serious bleeding, or cardiac arrest. And this trial was a negative trial. Trial showed no significant benefit in catheter ablation over medical therapy in reduction of composite endpoints of death, stroke, serious bleeding, or cardiac arrest. There are some criticism to this study, but the bottom line, the study was negative. The major criticisms were lower event rates than expected. There were a lot of patients that crossed over from medical therapy to catheter ablation which diluted the benefit effects of the ablation. So how do we do pulmonary vein isolation? So there are different techniques and different source of energies. The goal is to isolate the pulmonary veins from the rest of left atrium. So on the left-hand view, you see the electroanatomical map of the left atrium. To orient you, you're looking from the left atrium from the back. From the back, you see then the left-hand view, you're looking from the back. And there are four veins entering to the pulmonary veins. Purple means healthy and voltage. And as you see, there's extension of the voltage inside the pulmonary veins. And these sleeve of tissue inside the veins, they're known to be trigger of atrial fibrillation. And in the post-ablation, you see after delivering a point-by-point RF applications, there is no electrical signal in the veins. And red means no electrical activity. Purple means healthy and electrical activity. So that's the goal is to isolate the pulmonary veins and make sure there is no electrical activity in the veins. There are different other ways of doing pulmonary vein isolations. And one of the other major source of energy is using cryo-balloons. This is a Medtronic Arctic Front cryo-balloon that has FDA approval now in the US. And essentially, you insert the balloon inside the left atrium. You put it inside the pulmonary veins. You inflate the balloon and you put the freeze on. And essentially, you kill the rim of tissue around these pulmonary veins. On the left-hand view, you see the electroanatomical map of one of the patients who had the pulmonary vein isolation. And again, purple means healthy and activity. On the top panel on the left, you see there's electrical activity inside the pulmonary veins. And the bottom left, you see after the ablation, there's no electrical activity in the vein. So this is the purpose of the pulmonary vein isolation. So there is a trial comparing RF-PVI to cryo-PVI. The major one is a fire and ice study. 762 patients with dry refractory atrial fibrillation were randomized to cryo-PVI versus RF-PVI. And the primary endpoint was a recurrence of AFib, AT, or atrial flutter or use of enteritis or a need for repeat ablation. And essentially, it showed cryo-ablation is as good as RF-PVI in management of dry refractory paxosomal AFib. And the safety overall, the safety was the same and efficacy was the same. Is there other methods of pulmonary vein isolation? There's a laser balloon, which essentially, there's a balloon on the left-hand side. Essentially, there's a balloon on the left-hand view. You see the balloon that goes into the left atrium. It has a fiber optic endoscopic camera at the beginning of the balloon. And you see on the right-hand view that you get a visualization of the vein and you insert it into the vein and you deliver laser points around the pulmonary veins and do the pulmonary vein isolation. So let me tell, give you a case study, a patient that who I want to go over the technical aspect of the procedure so you understand what's involved in the procedure. So 56-year-old man, hysterectomy, hypertension, hyperlipidemia, and apaxosomal atrial fibrillation. He was on flecainide for a few years. He had a very good symptomatic relief, but then started having almost weekly breakthrough episodes of AFib. So he was brought in for initial RF-PVI. So before we start the ablation, we need, we put a catheter up in the heart. This is from, you see there's a CS catheter on the top panel. You see there's a multipolar CS catheter. And also there's one on the, on the hyst. And then the first step is to go to a traceptor. There are different ways of going traceptor. On the top panel, you, you see there's use of fluoroscopy for going traceptor. You inject the contrast, you visualize fossil valleys, and then you go traceptor. On the bottom, it is using ice image for going, for going traceptor. You, you on the A panel, you see the, the, the round structure at the round structure is your left atrium. You see SVC, IVC, and a right atrium. And then as the, on the B panel, you see the needle drops into the fossil valleys. And then you go cross and you have access to the left atrium. You can, depending on the procedure and the type of ablation that you're doing, you may need one or two traceptors. Okay. Before I start playing this video, this is how we start the procedure. At least in, in, in our lab, we created, we use intracardiac echocardiogram to create a shell of the left atrium. And you see, that's the, that's the gray shell. And then we identify the veins and use that as a baseline for starting the mapping, the procedure. We go to traceptor in the left atrium. Now we have two catheters. One is this white catheter. That's ablation catheter. And this, there's a multipolar catheter. That's, we use it for mapping. And there's a CS catheter. That's, you see at the bottom, it's a blue color catheter. This video is 20 times faster than what happens in reality. Let me play it for you. So you understand how we create a geometry and create a 3D mapping. So essentially with mapping catheter, we enter into the veins and try to understand the geometry of the, the chamber. Also, we get a lot of information about the health of the chamber, about whether there's a scar and whether it's a distribution of scar. And slowly, slowly, as you see, there is a, you see the shape of the chamber. Purple again means healthy. Red means no electrical signal or dead. And there's a rainbow of the color between red and purple. That means different levels of scar. At the end, if you notice, we are again on the right-hand view, we are looking at the back part of the left atrium and the posterior wall is completely healthy. There's a few points of maybe scar, or it can be poor contact from the mapping catheter. And you see the red inside the veins means no electrical activity, but there is a lot of activity still at the beginning of the vein before we get really far out of the vein and there's no electrical activity. And this brown thing that you see, this is how we mark the esophagus because it is a critical structure. You don't want to ablate too much on the esophagus because there's always a risk of atrial fistula, although it's quite rare, but it's a catastrophic complication. Then we start doing ablation. This is, I'm just going to show you the ablation on the right side of the vein. I have already done the ablation on the left side of the vein. You see the pointing, point-by-point ablations on the left side. And now I'm going to show you the ablation on the right side. The ablation catheter has a contact force sensing, and it can tell me how much force I'm putting in the tissue. And I want to keep it consistent on the back wall. And then we can titrate the amount of energy that we deliver depending on whether you're on the posterior wall or anterior wall or on crino. You see, it's essentially point-by-point. You go around the veins and do the ablation. On the posterior wall, you want to have a lower energy, although there are some debate whether we can do high power, short duration to avoid the complications. And then you come to the anterior wall. If you notice here, before I started doing ablation, I went up from the superior aspect of the right pulmonary vein, anterior part of the right superior pulmonary vein. And generally you pace and you want to make sure in the area that you're burning, there's no phrenic nerve capture because always there's a risk of collateral damage to the phrenic nerve. After I'm done with pacing, I'm just pacing around, make sure there's no phrenic nerve, and then started ablating on the anterior part of the right-sided veins. And again, you can deliver the anterior part is thicker and it can deliver more energy and slowly, slowly you come down and you finish up the anterior part and back to the posterior wall, lesions there. And the blue dot here, it means that at this point, I already had the pulmonary vein isolation that there was no electrical signal into the veins. And I confirmed it because of the catheter sitting inside the pulmonary vein. And so I can visualize my signal as I'm doing the ablation. And I just finished it up because we are doing full circumferential pulmonary vein isolation. And then after that, we have to do something called entrance block and exit block. Entrance block means there's no electrical signal after the ablation. This is a paper that published in 2013. Essentially, you do exactly the same thing. You have a catheter inside the pulmonary vein. You see that before the ablation, there's electrical signal. On the left-hand view, you see the electrical signal inside the vein. After the ablation, there's none. On the bottom is a CS signal. Then you see there's electrical activity in the CS, but nothing in the veins. And the right-hand view, you pace inside the pulmonary veins, and you want to confirm that nothing can get out of the pulmonary veins into the left atrium. So this is called entrance block and exit block. Then I generally go back after 20, 30 minutes and remap and reconfirm that the veins are still isolated and there is no reconnection, acute reconnection. You see with a mapping catheter, I will go around. Recreate the voltage map of the left atrium. And at the end, there's nothing. So there's really no... Let me show you the final results, which is something like this. So the veins are isolated. There's no electrical signal inside the veins, and the back wall is healthy. Okay. This patient did quite well. He has been off of Flaconide for the last nine months and has not had any recurrence of atrial fibrillation. How about persistent atrial fibrillation? The patient that I showed you, the case that I showed you was a patient with paroxysmal atrial fibrillation, structured normal heart. Persistent atrial fibrillation is a different ballgame. Still, pulmonary vein isolation is the cornerstone of catheter ablation of atrial fibrillation. However, the success rate of standalone PVI in patients with persistent or long persistent atrial fibrillation is limited. And different ablation strategies beyond PVI have been proposed and the most commonly used strategies are ablation of continuous fractionated atrial cartogram or creation of additional linear lesions in the left or right atrium. Although most of these strategies were initially very promising, the follow-up studies have shown mixed results. So when it gets to persistent atrial fibrillation, each lab has its own way of doing ablation of atrial fibrillation beyond PVI. So how about future technologies? What are we going with? Where are we going with pulmonary vein isolation? Future technologies has geared toward single shot approach rather than doing point by point. RF was point by point going around the veins. Cryo ablation was a single shot. Essentially you put the balloon inside the veins, you freeze and that's gonna do the PVI for you. And most of the new technologies are heading to that direction to doing single shot approach. I put three different systems that are different levels of stages of development. Boston Scientific has a RF balloon, a Helios balloon from Biosense and Globe System. These are all different RF balloons that they can deliver RF inside the vein. The idea is the same. You put it inside the pulmonary vein. You can titrate the amount of energy that you deliver on the back wall versus anterior wall, and then you deliver energy as a single shot approach. Also, there are a few super cold, ultra low temperature cryocatheters. This is a Darjeel system that has a C mark in Europe and the ID study is in progress. This catheter uses liquid nitrogen as a coolant and it gets as low as a minus 196 degrees of Celsius. So it's pretty cold. And you can do the PVI ablation with it. You can isolate the back wall if you put a catheter on the posterior wall and then you can do the CTI ablation with it. And the last technology that I'd like to talk about that's coming down the pipeline and there's a lot of excitement about it is pulse field ablation. Pulse field is essentially is a train of microsecond high amplitude electrical pulses that you can deliver it as a monophasic or biphasic. And this can ablate the myocardium with electroporation essentially create small holes into the cell membrane without any heating. So it's quite specific to the myocardial tissue and it can potentially change the way that we do the ablation. Most of the catheters that are in development are again, they're single shot approach. I put three catheters here. One is on the left top is a Theropulse catheter. Medtronic has again, a circular catheter that you put it in the veins and can deliver RFPFA. And Boston Scientific is also has one. There are a few other companies are developing PFA catheter. On the bottom, it's a lattice tip catheter. This is more like RFPVI, RF catheters. It's a point by point ablation but the lattice tip catheter has a bigger footprint and the lesions are bigger. And the beauty of it is it can toggle back and forth between PFA and RF if there is any need. Okay, so this is a case of PFA. A friend of mine, Dr. Habibi from Valley Hospital in New Jersey sent me. You see there are CS catheter in the CS and there's a multipolar catheter, multi-electro catheter inside the pulmonary veins. And you see they deliver a single train of PFA and there is immediate isolation. You see the electrical signal coming along. And this is a PFA pulse. And then immediately after, there is no electrical activity in the vein and it's completely isolated. Okay, in conclusion, pulmonary vein isolation has emerged as one of the major tools for rhythm control strategy in management of atrial fibrillation. The ablation procedure has become shorter and safer in the last two decades. And at this point, pulmonary vein isolation using point by point RF ablation or cryobloom remains the cornerstone techniques in AFib ablation. There's other techniques that have FDA approval and there are many that are in development. And at this point, there are numerous exciting technologies in development and they may change the way that we do the procedure in the future. Thank you. Thank you very much, Dr. Karamadi for that wonderful presentation and insight into the deep spaces and clinical world of AFib ablation. That was very helpful for me. We have a few questions that I'd like to get to if you don't mind and we'll just get started. So one of the questions we have here is regarding the PBI. So you mentioned either RF or a cryobloom both being used for PBI. Out of curiosity, is one easier or does one or the other take less time? Is it preference of the physician? So I worked with both and cryoablation is generally, if you look at the clinical data in these trials, is generally shorter compared to RF-PBI. Each has its own risks. So cryobloom is known to, has more complication risks associated with phrenic nerve injury compared to RF. The other problem with cryo is if you want to do more beyond PBI in the left atrium, you have to have an RF catheter. If you want to do a linear lesions in the left atrium, then you have to have the RF catheter or you want to do CAFE ablation, then you have to pull an ablation catheter, RF ablation catheter to do more in the left or right atrium. So it comes, it's each of them, they come with their own risks, complications and benefits. The other thing is when you do RF ablation, it's technically more demanding because essentially you go point by point and you have to stabilize your catheter and make sure you are delivering the right energy at the right time in the right place. So it's each of them and it's all lab dependent. I see, that's helpful, thank you. The other thing you mentioned with the PBI is the circumferential approach. Is it always that or is it sometimes done only partially or is it always the full circumference? So the way that the AFib ablation started, it was not circumferential, it was segmental and then became circumferential and then like osteo, you go around to the osteum of the veins and do the ablation and then slowly, slowly move to wide area of circumferential ablations. Essentially you try to get and do the ablation on the atrial tissue rather than the vein tissue. Because the data show that a wide area of circumferential ablation is more effective than doing osteo lesion and also osteo lesion, the risk of pulmonary stenosis is slightly higher. So it's done differently. Sometimes you go into the atrium and there was a PBI before and now you see there's an area, there's a gap and instead of going all the way around the veins, you just go in and do a segmental PBI. You go and do the few RF applications in the gap area and then you finish it up and you still perform a PBI but it's segmental now because you already had lesions in other places. I see. Thank you. Okay, let's look at our next question coming in. Okay, you also had a slide where you referenced the single transeptal versus the dual transeptal. Can you elaborate a little bit on how you determine which approach you need to do? Like, is it something clinically related to the patient's anatomy or what's the decision process for doing single versus double? So for cryo-PBI, generally it's a single transeptal. You just need one transeptal sheet to do the cryo-PBI. For RF-PBI, it's operator dependent. You can do single transeptal and double transeptal. Single transeptal, you will have one catheter in the atrium at a time. So you cannot have two catheters at the same time. So what's a downside? What's good about having two transeptals? So if you want to do something more than veins, you always, and you want to do linear lesions. So you want to do a roof line. You want to confirm that roof line is blocked and having two catheters is nice because you can paste from one side of the line and measure and make sure nothing can get through to the other side of the line. You can do it with a single catheter, but it's not elegant and it's not perfect. So most operators, we want to do more than PVI. Generally, they get two catheters across to do PVIs. In my lab, I always do two transeptals to go cross-morph my PVI and keep my mapping catheter in the veins, confirm there's isolation. I use it if I need to do more ablations beyond PVI. I use to make sure there's a block across the line. I see, very helpful. Thank you. Let's see, next question. So despite technical advancement in the field, what patient types do you typically see reoccurrence of AFib after the pulmonary vein isolation? Is there a particular patient type? So two points. One is for RF-PVI and cryo-PVI both, we see a lot of vein reconnections when they come back with recurrence of HF fibrillation. What does that mean? It means we go back, we do the PVI, they come back two years later, one year later, three years later, whatever. With recurrence of HF fibrillation, we go back to the atrium and we map and we realize one, two, three, or even four veins, they're all reconnected to the atrium. It means they're electrical connection now back into the veins. And reconnection rate is quite high. It's around, depending on the trial that you look at, 20, 30, and even up to 60% of patients will have a reconnection. And this is the main reason the AFib recurs after pulmonary vein isolation. And this healing, the body heals, the lesions are not perfect, and we see a reconnection. At the time of the procedure, you think you killed the tissue around the veins, but when they come back, you realize, no, there was stunning from the ablation rather than being a true permanent damage. This is point number one. Point number two, persistent patients, they generally come back with recurrence. If they come back with recurrence of HF fibrillation, or if you do a lot of ablations, like linear lesions and cafe ablation, they come back with atrial tachycardia, more organized rhythms, but they still, they come back. And the substrate is different in persistent patients. In paroxysmal patients, the atrium is healthy. Everything is normal. Conduction velocity is normal. And the veins and triggers are more important. But in persistent patients, there's something more than just triggers from the veins. There are, substrate is not normal. The voltage is not normal. There's the patches of scar in the left atrium that it can be a substrate for rotors and AFib initiation and maintenance of AFib. So persistent patients, they come back more. And as the left atrium dilates more and more, the chance of recurrence is higher. I see, makes sense. Very helpful. So they're a much more complicated case in the persistent. Yes, especially in persistent and long persistent patients. They come back. The chance of success rate is low. And sometimes you need to do medication and ablation. Still, there's a good chance that they may come back with more AFib. You mentioned the pulse field ablation. That's a newer technology on the market. It is coming down the pipeline. It's not in the market yet. It's not in the market yet, but it's a future technology. You mentioned, you anticipate like that would be done in connection with other ablation strategies. Is that your sense typically? Or do you see strong advantages of the pulse field ablation over the other methods yet from the trials or studies? So the studies, they have been very promising. So, and the main, there are two points. One is the safety of pulse field ablation. And it looks like it has a myocardial specificity. It means it's just does the ablation only in the, affects the myocardial tissue, rather than affecting esophagus that's sitting just three millimeters away from the ablation catheter. So if it can only affect the myocardial tissue, it's going to be very selective to myocardium. So the risk of complication, hopefully it's going to be lower. The other thing is the risk of reconnection. And this is something that we need to see. Some trials, some studies that's just limited number of patients, they showed there's, the reconnection rate was almost 0% for one of the technologies that's coming out, but we still need to see. This is something that they're generally, when the new technology comes out, there's a lot of excitement, but we need to really rigorously test it and make sure that's really what we want to do in the future. But if it, that's the connection rate is zero and the safety is better, that's going to be the future of the PBI. The other point that you made about in connection, are we going to use PFA next to the RF or PFA only? It is something that, again, we need to see. There's one catheter that can do both. And that's a ferropulse lattice tip catheter that can talk, go back and forth between RF and PFA. And we will see, we will see whether that there's any benefit to this. We don't know yet because data is limited so far. Yeah, we need to see the longer term efficacy and see what happens. So the explanations on the ablation strategies were very helpful. I know we have a lot of questions coming in about documentation of such strategies. And sometimes when data abstraction is happening for the registry and the medical record, there will be different terminology seen. And for example, you might see documentation of roof or posterior wall or LA line ablations and how they get coded. So when you talked about roof, I heard you mention in your presentation earlier that a roof is a type of linear ablation. That's exactly right, yep. So you can do different ablations in conjunction with your PVI. If you, for example, if you have a patient with persistent AFib and you want to isolate the posterior wall, you can just put a roof line and then floor line and call it a box lesion set and isolate the posterior wall. So two linear lesions in the back wall. Or you can just do point by point and essentially paint the whole back wall. So that's a different strategy. For example- But those are all types of linear. Those are all types of linear ablations. Ablations. Or another linear ablation that you may want to do, it's called mitral line. You start from the one of the pulmonary veins and extend it all the way to the mitral valve to prevent perimitral flutters. And then you can do CAFE ablations. If you are in atrial fibrillation, you look and look for continuous and fractionated potentials and ablate those areas. That's CAFE ablation. The other ablation, if you do, if you go ahead and do your PVIs and still you have atrial tachycardia that's coming from somewhere. And you can map that atrial tachycardia and do focal ablation, right? You go and there is an additional focus that's firing and it's driving your heart rate. You can go ahead and ablate that one. That's called focal ablation. Generally, these ablations are more for patients who have persistent nature of fibrillation. For paroxysmal atrial fibrillation, most operators, again, it's operator dependent. They only do PVIs unless they notice some scar and force to just make sure that scar cannot be the cause of another atrial flutter. They may do more, but mostly paroxysmal atrial fibrillation, veins only, persistent, the operators decide what to do. CAFE ablations, focal ablations, linear ablations of the right or left atrium. And that's about it. Very helpful. Thank you. I think we have time for one last question here. You talked a little bit about the mapping catheter and what it's used for. So with the mapping catheter that's done first, you mentioned, is this correct, that you're using it to identify scar tissue or kind of geometry of where you'll be performing the ablation? Is there anything else? So mapping catheter, it's generally, first of all, you can do the whole procedure with a single ablation catheter. If you want to do it, you can do the whole thing with ablation catheter. Mapping catheter is generally multi-electrode. So instead of having, ablation catheter is one, four electrodes, but two bipolar electrodes. But mapping catheter, they have different numbers of, different number of electrodes. Again, they have up to 64 electrodes, even more in some of them. So at this one heartbeat, you can gather more information and it's going to make the procedure fast. So it's, you create a geometry, you understand the substrate, you understand whether there's a scar tissue, you understand the voltage, you understand the area that you want to ablate. And also it's going to help you if you have two transceptals with mapping catheter and ablation catheter, you can do a differential pacing and make sure the lines are blocked. If you are doing more than PVI, just make sure the lines are blocked because linear lesions, although you may think it's just a line, but in reality, sometimes it's quite hard to achieve bidirectional block across the line. And having the ablation catheter may help, and I'm sorry, the mapping catheter may help to make sure that they're really blocked. When you look at the data, some trials and studies shows up to 60% of these lines are not blocked when they go back to the atrium to re-look at these lines. So the mapping catheter may help to achieve bidirectional block across the line. Wonderful, that's very helpful. Well, I want to let you know that we deeply appreciate your time and sharing your clinical expertise with us today. I know I learned a great deal, so thank you very much for your time. I want to also thank our audience for joining us today, and I hope you learned as much as I did. And we'll see you at the next session, and thank you again. Have a great day. Thank you.

AFib ablation

technical aspects

past procedures

present procedures

Cox Maze procedure

cather ablation

pulmonary vein isolation

future technologies