Good morning everyone. My name is Vidal Esebag from McGill University. As we're just getting set up, the presentations will be heard exclusively through the headsets, obviously. In terms of questions, there is the Q&A on your app. If you want to submit questions through the Q&A, hopefully it'll work and I'll be able to see them on my phone and do the questions. The presentations will be a maximum 10 minutes each and we'll leave two minutes for questions between each presentation. There's five presentations in total. I'm looking forward to an exciting session about use of PFA outside of the pulmonary veins, posterior wall and lines. I think it's an exciting topic. It's something that many of us are starting to do, but we still need a lot of data and evidence as to durability, success rates, as well as risk of pro-arrhythmia using these strategies. So without further ado, it's my pleasure to present Peter Neuzil from now Molse Hospital to proceed with the first presentation. Thank you, thank you. Thanks a lot. Okay, so it's my great honor on behalf of my all co-authors like Honza Petru, Toshi Funasako, Jacob Krut, Pavel Hala, Honza Shkoda and Vivek Reddy to present the first in-man clinical data from the feasibility and durability clinical study, which focus on using nanosecond pulse field ablation system. So it's my real disclosures. And so why we need to have nanosecond pulse, which is like 100, roughly 100 shorter than the microsecond used. And we can discuss with the experts for biophysics that what is really nanosecond, what is really microsecond. But what we really expect is deep lesion. What we can expect less thermal effect. But it's not true that the pulse, I mean, electroporation doesn't produce any thermal effect. So we know that. And actually what is very interesting effect, maybe potential very interesting effect is to get less muscle irritation. So this is 11 French catheter going on the two rings, the metallic rings is outer ring is like 30 millimeter and the inner ring is like 22 millimeter. And in between the bipolar ablation, which is a really 360 degrees circumferential, and which is very, very effective in terms of giving no gaps and the potential effect. Actually, it's not potential, but it's real effect is that we can minimize the number of bipolar ablation, which can cause less hemolysis and less other unnecessary effects. So on the catheter, if you see this on the left side, so on top of this two rings, there are five digits with each pair of electrodes for sensing. And actually the last set of electrodes is on the shaft. So you can visualize the catheter even under, I mean, all this electronical mapping systems. But there is no any sensor there. Okay. It's no sensor. So as a nano PFA effect, it's going deeper lesion. As I said, we really protect all this extracellular matrix and we probably can reach really just not really reversible, but clearly irreversible effect. So irreversible is the issue. So this is just example of our workflow. On the left side, you can see the flow. The catheter is matching the PV. So like on the left point of vein. And actually in the catheter, this is the catheter, but we use three different mapping systems for this 22 patients. I will talk later about it. So you can visualize the catheter very nicely, even on the catheter, because we customize the catheter and this catheter together. And we are always using eyes to set up and to get, I mean, idea about real contact. It's no contact sensor. So like no contact force even, but actually you can, on the floral, you can say like, we say like mushroom, bigger mushroom shape. So we can assume the effect, but you need to be very careful not getting these two rings together because then you can get arcing. So nicely placed, but this is some example of a new patient, but this 22 patient was based on like PV isolation, which is clearly here, but this is a better mushroom shape. And this is like a catheter sitting on the posterior wall. This is like another example of placement, the osteoplacement, the same way, the more anteroplacement, the same way. And so you can minimize the number of patients that will show the results. So first immense study was based on 22 patients, the mapping catheter I introduced, and we use all these three, not all, so we have no arrhythmia, but we have arrhythmia, but we didn't use the arrhythmia. So it was Kato, Navex, and NXT iMap system. And the catheter was used for mapping. It was not just like only ablation, we did mapping was like pentanol or something, so we really use this catheter for mapping, and we send the patients, every patient, 22 patients, for three months, which is now getting to be standard for remap. And the ablation, the nanosecond pulse ablation, it's written here at 2.55, but actually we use more 5 than 2.5 in this particular study. So getting to the results, so we did only 22 patients, 86 PVs were acutely isolated, all patients got isolation of the posterior wall, acute effect. Then after three months, we got five reconnections, five veins reconnected, one reconnection on the posterior wall, which is clearly the first in man, so it's an exciting effect. And actually, if you look at this number of applications per PV isolation and per posterior wall, it's fantastic. So we have less than five applications on the posterior wall, we have around like 12 applications on the PV, so we clearly can minimize the number of ablations. And the dwell time, and this is really something we can minimize, but fluoroscopy is not represented, because I need to repeat it, it's first in man. So I will give you some examples. This is a catheter position on the posterior wall, which created this, this is a NAVEX map, so acute NAVEX map, and then three months later it was done with catheter, it's 80 days shorter, so it is like less than two hours of procedure, but we spent really time by mapping and remapping, so it's not like clinical study data, it's not real practice. Fluorodyne was okay, so I will show you next example. This is catheter sitting again on the right side position, and this is much better, because we use here like only five minutes fluoro, so patient by patient we minimize the timing, and we can clearly get this result. All maps were done with catheter, so this is fancy, it's like stitching out like number five PV, so it's like really strange anatomy, by the way it's like, it's NXT system, we use for the mapping, acute mapping, and if you see this, fluorodyne was like two minutes, so we can really patient by patient minimize, and we as well minimize the number of applications. So I can go for conclusions, so ladies and gentlemen, let me conclude that nanosecond pulse ablation, the circumferential is real circumferential catheter, is successfully used, we can minimize the number of application, we can use it with standard mapping system, depends on the company, depends on the next development, which kind of mapping system will be the leading, but we customize the catheter for this much better, because we can really follow the shape better, and actually next steps we need to get randomized trials and usual to get for something more interesting. Okay, so thank you so much for attention. Thank you very much, excellent presentation, any questions, there's one over there. Come to mic, it's better to come to mic, I was here like last... Or if you use the app you can put a question in and I can repeat it. Okay, perfect. Jack, my question is, obviously the nano PFA, it will try to reduce the deeper lesion, but also the less muscle contraction. Well, actually I didn't mention, it was written in the presentation, that actually we randomly use like general anesthesia, and even with this very first group we use deep sedation. Deep sedation. And we can use like propofol in our hands, so actually a lot of guys know that, so actually it's very feasible, but you know for us the remapping was a little bit like, so we were cautious to protect the movement of the patient. Okay, but movement of the patient is minimal, because it's like less irritated, okay. I need to say, I don't know why, on the right side is more pronounced than the left side, the movement. Right, thank you. Any other question? Okay, thank you very much. Thank you very much. Okay, so the next presentation is going to be about pulse field ablation for PVI with or without posterior wall, and it's a pleasure to have Marta Lorente Ross to present. Thank you. Good morning, everyone. Thank you all very much for attending this session. My name is Marta. I'm a cardiology fellow at Georgetown University, and it is my pleasure to present our work on posterior wall isolation in addition to PVI in patients with persistent atrial fibrillation undergoing pulse field ablation. So we all know that additional ablation strategies beyond the pulmonary veins have been proposed to improve the outcomes of catheter ablation in patients with persistent atrial fibrillation, however, with rather disappointing results. So why does the left atrial posterior wall remain such a target of interest for catheter ablation of atrial fibrillation? Well, it has certain characteristics that have convinced electrophysiologists of its crucial role in both initiation and perpetuation of atrial fibrillation. Part of it is the common embryologic origin and gene expression with the pulmonary veins. In addition, there's anatomical considerations. The subendocardial and subepicardial muscle bundles are anatomically distributed in a way that promotes anisotropic conduction and reentry. There's also the anatomical proximity to the inferior ganglionated plexi, as well as the degree of endocardial-epicardial dissociation that we find in the posterior wall. So after decades of experience with thermal ablation, what did we know? This is a summary of the clinical trials that compared PVI only versus PVI with posterior wall isolation for patients with persistent AFib. As you can see, they all had very mixed results. The Kaplan clinical trial, being the most recent one, deserves special mention, which was negative. However, in a pre-specified subanalysis, there was a suggestion that maybe a certain subselection of patients with persistent AFib are those who benefit from posterior wall isolation. With the introduction of pulse field ablation, what do we know so far? We know that it's safe from the initial results of the PERS-AF1, and with its advantages of myocardial tissue selectivity and preservation of left atrial function, we know that it's effective. We know that there's lesion durability. However, the question remains, is there added clinical benefit to this? This is a summary of the observational studies that have been published so far with pulse field, comparing PVI only to PVI with posterior wall in patients with persistent AFib. To the left, we have the study of Gunawardin and colleagues, which was negative. In the middle, we have the results of the Manifest PF and the Athena registries. And to the right, the recently published results of the Euphoria registry, all of which showed no benefit of additional posterior wall isolation. So our goal was to study the role of adjunctive posterior wall isolation in addition to PVI on HLA arrhythmia recurrence in patients with persistent AFib undergoing pulse field ablation. These are the preliminary results of an international multicenter retrospective study. We included all patients with persistent HLA fibrillation who underwent pulse field ablation from April to October 2024. For primary outcome, we studied recurrence of HLA arrhythmia. For secondary outcomes, we looked at procedural time and procedure-related complications, and we applied standard statistical tests to study this. During the study period of all patients who underwent pulse field ablation, 287 had persistent AFib, 55 of which underwent PVI only, and 232 underwent adjunctive posterior wall isolation. We'll start with the baseline characteristics, and I'll point out a few things here. The mean age of our study population was 67 years. 28% of patients were female. And patients who underwent adjunctive posterior wall isolation, compared to those who underwent PVI alone, had a higher prevalence of hypertension, heart failure, and a higher CHA2DS2-VASc score, with a lower prevalence of coronary artery disease. There were no differences in other baseline characteristics, including left atrial size, use of antiarrhythmic drugs, or type of anticoagulation used. For our procedural details, all of the cases were performed under general anesthesia using a standard ventilation and with the Farah Pulse technology. Things to point out here, 22% of cases were redo ablation, which were equally distributed between groups. Serofluoroscopy was used in 13% of cases, more frequently in those who underwent adjunctive posterior wall isolation. Intracardiac echocardiography was used in about two-thirds of cases. Transceptal puncture was done with Versacross in two-thirds of cases, and BRK needle in the remaining third. And it was guided by TEE in a little bit less than half of patients, and by ICE in over half of the patients. The total number of PFA applications was 56 for all patients, which was 36 for the pulmonary veins, and a median of additional 14 applications to achieve posterior wall isolation. Further applications were required for the pulmonary veins after first pass in about 6% of cases, and the same for the posterior wall. And additional lesion sets included mitral line in 10% of cases, CTI in 20% of cases. In 17% of cases, adjunctive use of radiofrequency was used. All of these cases were for the purposes of either the mitral or the CTI line, but not for PVI or posterior wall. For our primary outcome of recurrence of atrial arrhythmia, we had a median follow-up of four months, which was similar between both groups, and 20% recurrence in the PVI-only group, 19.8% in the adjunctive posterior wall group with no differences between groups. And to your right, you can see the Kaplan-Meier curves for both groups with the PVI only shown in blue and the posterior wall in green. How was the primary outcome assessed? Well, in most cases, it was done by ECG only during clinic visits. This accounted for 39% of all cases. The second most frequent form of monitoring was Sciopatch, which was used in 15% of all cases. And the use of Holter, cardiac smartwatch, device interrogation, or ILR was used less frequently. And here you can see the percentages for each group, again with the PVI in blue, the posterior wall in green, and with no differences in the mode of monitoring between groups. For our procedural times, we looked at the total procedural time, the left atrial dwell time, and the fluoroscopy time. The graph is showing the median and interquartile range with the PVI group shown in blue and the posterior wall in green. The skin-to-skin time was similar between groups, 96 minutes for posterior wall versus 83 for PVI alone. The left atrial dwell time was significantly longer in patients undergoing adjunctive posterior wall isolation, 32 minutes versus 23 for PVI alone. And the fluoroscopy time was similar between groups, 13 versus 11 minutes. Finally, going into our complications, all of our events of complications were in the patients who received adjunctive posterior wall isolation. However, due to the low event number, there were no differences between groups. We had five events of minor vascular access complications, all of which were in the form of hematoma, not requiring blood transfusion or vascular intervention. Two events of pericardial effusion, one event of clinical pericarditis, one event of ischemic stroke, one event of acute kidney injury, and two events of pulmonary edema. Before we conclude, I would like to acknowledge some limitations, not only the inherent bias associated with a retrospective study, but the selection bias that can be introduced when the decision to pursue adjunctive posterior wall isolation had already been made by the operating electrophysiologist. Secondly, the relatively short follow-up time with a lower recurrence of atrial arrhythmia than what has been described in other observational cohorts. That would, of course, be expected to be higher with longer follow-up. Thirdly, the mode of follow-up, which, as you saw, was mostly with ECG only during clinic visits and a relatively infrequent use of longer-term cardiac monitoring devices. And finally, we did not account for blanking period antiarrhythmic drug use, and not all of these cases were first case ablations, but we also included redo ablations. With that, we can conclude that our study confirms safety, acute procedural success, and rapidity of posterior wall isolation using pulse-filled ablation in patients with persistent atrial fibrillation. However, our results do not suggest clinical benefit of adjunctive posterior wall isolation in patients with persistent AFib, and future studies should perhaps focus on which subselection of patients with persistent AFib would benefit from posterior wall isolation, especially given the results of the Kaplas study that we were left with on the literature from radiofrequency ablation. With that, I would like to thank all of my mentors at Washington Hospital for their constant support, as well as the Brigham and Women's Hospital for allowing us to participate in their registry. Thank you very much. Excellent. Thank you very much. There is one question from the audience asking about whether there was any specific protocol to confirm posterior wall ablation or isolation. Yeah, so the about 70, 98 percent of cases had post ablation mapping, so that was the most frequent form of assessing whether this had been achieved at first pass. It was post ablation mapping, and then in about 25 percent of cases, in addition, there was assessment for bidirectional block, which was mostly the cases coming from a center in Europe. So I would say mainly post ablation mapping, with a few cases in addition having confirmation of bidirectional block. Any other question from the audience? I'll have a couple of comments. First of all, STAR AF3 has completed enrollment, so in the follow-up, we'll have yet another study to give us some information, at least with radiofrequency ablation, as to the benefit of the posterior wall. And congratulations on, you know, on an excellent study. It is observational, and a couple of things you alluded to. One was the monitoring. You presented the graph. It seemed like there was a tendency for the posterior wall group to have more intense monitoring, so that may have a difference on the event rate detection. And then you alluded to the bias. There wasn't a protocol for who received posterior wall or not, so there may be a tendency that if the operator decided not to include the posterior wall, maybe that was a patient population that was less sick, or had a greater likelihood of benefit from a PVI alone. Any other question? Oh, there's one. What PFA system was used? I think you said it was all Firepulse, right? Yeah, it was, yeah, it was all Firepulse. Anything else? Excellent, thank you. Thank you. So, our next presenter will be Martin Fiella, mitral isthmus block and recurrent perimitral reentry tachycardia in patients undergoing PFA for long-standing persistent AF. Thank you very much. Good morning to everybody. Thank you for the word. It's my pleasure to have this talk here. Between October 2021 and March 2025, we did 440 PFA procedures for long-standing persistent HL fibrillation. And the median duration of continuous AF prior to ablation was 18 months. And for example, the Lavi was 50 milliliters. As regards the index ablation strategy, PV isolation was always the first step, which was followed by posterior box lesion as the second step. And by ablation at the mitral isthmus usually extended along the endocardial course of coronary sinus and the garment of Marshall as the third step. We don't do any ablation at the anterior wall to protect early appendage activation. And this was indeed preserved in a majority of patients, despite structural changes that we expect in these patients. Finally, the ideal endpoint of the whole procedure was termination into sinus rhythm. And this was achieved in 39% of the patients. And the remaining patients were cardioverted at the end of the procedure. And at the end of the procedure, the mitral isthmus block was assessed. It was evaluated during pacing in the appendage using faraway catheter and defined as a reversal of the activation sequence in the coronary sinus and quantified by the interval from the pacing artifact to the distal CS bipole. And when we look at immediate efficacy in mitral isthmus block, it was evolving over time. It was 92% for the whole population, but only 82% for the first 81 patients by the end of 2022. And this was largely affected, I think, by the concerns about possible damage to the coronary arteries that was first reported at the time. In the later patients, it improved to 94%, but it's still relatively far from absolute efficacy. And repeat ablation was performed in 66 patients in 70 procedures. And at the onset of repeat procedure, AF was present in 25 patients and could be terminated in 12 of them. And if you look at the picture, the conversion sites were all at the border or outside the prior PAV lesions. And in five of these patients, AF converted to HCL tachycardia. And together with those 45 patients with primary current tachycardia, we had a total of 50 procedures in which HCL tachycardia was present. And in these 50 procedures, we could identify 78 distinct AT types. Approximately half of them were macro entries dominated by perimitral. There were a few typical flutters, and there was complete absence of roof dependent. The other half was constituted by localized sources. And again, if you look at the picture, the sources were located at the border or completely outside the prior PAV lesions, except to localized re-entries from within the left PV antrum. And we look at it in detail at the perimitral re-entry. 37 were due to absence of mito isthmus block at the index ablation, but 63% were due to recovery of the mito isthmus block. And this is a large number, I think. But at this point, I have to say that we don't know the recurrence rate for the whole population because we didn't do any systematic re-mapping, and all of these repeat procedures were indicated by clinical condition. But probably we can draw some information from those patients with repeat ablation who didn't have perimitral re-entry. And I can tell for sure that at least 14% of them had recovered mito isthmus block. But the number is probably higher because there was a substantial proportion of patients in whom we couldn't determine the status of mito isthmus block before we started repeat ablation at the mito isthmus. Let me also mention the safety data because we are talking about 500 complex procedures. And we did have, among this population, two altogether, three in history, acute renal failures. And all of them occurred by the end of 2022, which was at a time when I think no one was openly talking about this issue. And with recognizing the problem, with strict fluid replenishing and avoiding prolonged hypotensions during general anesthesia, we haven't seen any further renal failures since, even in those complex procedures for long-standing persistence in whom a large number of PFA packets were given. And we, as I said, we didn't have PFA packets were given. And we haven't seen any coronary complication that would be clinically relevant. I have to say that ST segment depression is very common, but ST segment elevation is quite rare. And all of them were transient and receded either spontaneously or after nitrate. So let me conclude that in patients with long-standing persistent atrial fibrillation who undergo bipolar PFA with farapals, mito isthmus remains a challenge. Otherwise, all the recurrent sources of atrial fibrillation or atrial tachycardia emanated from the locations outside the prior PFA lesion. Recurrent AT is dominated maybe even more than in the history of radio frequency over recurrent AF, approximately 2 to 1. And macro-oriental and localized AT, as we were used from radio frequency, were represented approximately 50-50. There was complete absence of roof-dependent, which corroborates effective posterior box lesion. The efficacy in routine mito isthmus block is not 100%, or at least in our hands. And from the clinical point of view, recurrent perimitory entry accounted for nearly half of the recurrent atrial tachycardias. And more than 60 of the cases were due to mito isthmus block recovery. And finally, it's important to say that mito isthmus block could be always finalized, either with Farrapals or with radio frequency. But we definitely need a longer follow-up to understand the true durability and possibly the need for other options like alcohol ablation or unipolar PFA. Thank you for attention. Thank you very much. There are two questions on the poll. The first question was, in the cases presented, when there was a failure to achieve mito block, was RF or ethanol used in those cases? No. Well, actually, the repeat procedures were performed at the beginning. We wanted to at the beginning, we wanted to remap the atria. So many of the cases were done by radio frequency. And in most of the cases, the mito isthmus block was finalized from the coronary sinus. And later, I would say that PFA with Farrapals again prevailed, except those cases when we saw sources from the anterior wall or from the septum, where we felt that ablation with Farrapals would be dangerous because of appendage or conduction system. Yeah, the second question was, did you go into the CS to ablate? So there were cases where you used RF from within the CS on the redo? Yeah, that's what you just said. Okay. There's another question about how many deliveries of ablations were used and was ablation performed in the left superior pulmonary vein? For left superior pulmonary vein? Yeah. Well, for PVs, we usually have something around 40-50 because it's this really wide area. So it's not eight plus eight, but maybe around 40-50 PFA trains were given for PVs and the rest for posterior wall and mito isthmus and coronary sinus as well. I have a last question for you. It's a broad wealth of experience of patients where you've done these lesion sets and obviously there's always the risk benefit to consider. It's very interesting that you presented zero recurrence of a posterior wall flutter. That seems to be the lesion that's most durably achievable and doesn't cause proarrhythmia, whereas a majority of the recurrences seem to relate to mitral isthmus that you could consider a proarrhythmic effect perhaps of ablation. With all of this experience, do you think that the mitral isthmus should be targeted routinely with this technology or is there some feeling that maybe sticking to the pulmonary veins in the posterior wall for patients without clinical flutter may make sense? You know, we have hundreds, maybe thousands of patients with long-standing persistent atrial fibrillation with radiofrequency doing the business for 20 years back, maybe longer, and sooner or later you will have to ablate. You know, you have to get rid of dependent perimitral. Perimitral is sooner or later returning, so I think that's why we selected also this ablation step and in addition coronary sinus and ligament of marshal is the major source in addition to PVs. So the area actually overlaps, so that's why we selected the third step and it's not only mitral isthmus, it's longer, longer endocardial course of CS actually. Yeah, yeah, maybe just come to the mic. So Martin, excellent presentation, maybe I miss it. So do you use routinely nitrates per treatment for mitral isthmus? No, nitrate. Nitrate. No, no. Why not? As I said before, we see, commonly we see ST-segment depression, it's always transient. And ST-segment elevation is quite, quite, quite rare. We have seen, we proved that we have a 50% of spasm on the mitral isthmus when you have atrial, so actually it's something, but it's, I'm not speaking about symptomatic, I'm speaking about like spasm, so because a lot of spasms are asymptomatic surprisingly, right? I will be frank here, I gave nitrate once for ST-segment elevation and disappeared within seconds after nitrate. All of three or four other cases disappeared within one or two minutes spontaneously and there were no clinical sequel as far as I know. A quick one maybe. Do you do any acute remapping of the mitral isthmus block? Like you achieve the block but maybe 10 minutes later you check if the block is still there? Well, again, it's a good question because in the workflow of the lab you usually have five minutes for checking and the limitation is that you don't have any measurement at the endocardial aspect of the mitral isthmus. You have only CS, just one, having one catheter in the left atrium which is far away, you can pace with far away appendage and look at what you see in the coronary sinus and the limitations are of course because the coronary sinus position of the coronary sinus catheter may be not optimal, may be isolation of the coronary sinus so that you don't see anything laterally or postulatally. Okay, thank you very much. Okay, next up we have Byung-Soo Kim to present an anterior mitral line with pulse field ablation acute and intermediate outcomes. Good morning, everyone. My name is Bum Suh, one of the EP fellows from NYU, and it's my honor to share our experience of enteromitral line ablation with the PFA, specifically the five-spine fire pulse ablation. So, as we've been speaking throughout this morning, the PFA has been evolving and has been very successful in terms of pulmonary vein isolations. However, the efficacy and long-term durability of the ablation elsewhere is still remaining a little bit questioned. And enteromitral line and enteroval ablation in general remains a little bit challenging, even with the radiofrequency ablation, due to its different embryologic origin. Also has different tissue characteristics, such as increase in wall thickness, has a lot of epicardial connections. So, as we were doing a lot of ablations with the PFA catheters, now we wanted to look at the durability of the enteromitral line we were creating with the PFA catheter. So, the way we did it is that we collected 80 consecutive patients who ended up getting a PFA ablation for their AFib procedure, and also had the enteromitral line created during this time. And as a comparison, we also collected the patients during the similar period of time who had the radiofrequency ablation for their AFib ablation, and ended up getting the enteromitral line ablation to compare. Whether the enteromitral line was created because there was a scar for homogenization, or whether it was due to the mitral flutter that was induced during the procedure, or both, were up on the operator's discretion. And the amount of dosing, as well as the configurations that they used to create the mitral line, as well as confirming the bidirectional blocks, were on the operator's discretion. But all cases were done using the electroanatomical mapping, as well as the ISA. After the index procedure, patients were followed at our arrhythmia clinic in two to four weeks as a post-op follow-up. They received the ECG at the time, and afterwards, patients had the outpatient cardiac monitoring in three months, six months, and 12 months follow-up periods. Our primary efficacy endpoint was the freedom from a composite endpoint of initial procedure failure to achieve the isolation. Documentation of the tachyarrhythmia that's lasting more than 30 seconds after the blanking period. Use of class one or three enterothermic medications after the blanking period, and or patient having recurrent tachyarrhythmia requiring further rhythm management, including the cardioversions or the redo ablations. The primary safety endpoint was the composite of the usual post-AFib related series of adverse events. So looking at the data, this was our patient demographic for the PFA population. It tends to be a little bit elderly, just like all our AFib patients with the average age of 75. In terms of sex, male and female was almost evenly distributed. The chest VASc score average was 3.7, and proxysmal versus persistent was about half and half. Majority of the patients were on NOAC, and this was the recurrence of the atrial fibrillation, atrial tachycardia during the follow-up periods of average of 160 days. We had about 30% of patients who had the recurrence of AFib AT, and when we look at the difference between the subgroups of proxysmal FIB patients versus persistent FIB patients, the persistent FIB patients tends to have a higher number of recurrences. However, when we compare statistically, there was no difference. And looking at the effect size with the Cramer's V also showed a very small effect size as well. Now, so we wanted to look a little bit closer into this, because when we decide to use the PFA ablation versus RF, we often consider is this the first time ablation, is this a redo ablation, was there entero mitral line that was done before, or is it the de novo lines? So for the first time ablations, we divide a group into the patient who just had entero scar and operator decided to homogenize the area with entero mitral line versus the patients actually had a mitral flutter induced versus both. And for the redo ablation group, we decided to look at the prior entero mitral line was drawn versus not. Statistically speaking, there was no difference. The group that had the most efficacy or the highest success rate were the people who had the first time ablation with the induced mitral line, induced mitral flutter during the procedure without any scars in the entero wall. However, when you do the post hoc pairwise test and correct the P values with the homeboom Faraday corrections, there was no statistical difference among these groups. So how does the PFA is comparing to the RF that we've been doing for years? The demographic wise, the radio frequency ablation group was almost identical to the PFA group. And this is the Kaplan Myers curve of the event rate. The PFA and RF group, PFA had tends to have higher event rate across the follow up periods. However, there was no statistical difference with the low rank test P value of 0.4. So we decided to look at a little bit closer into the subgroups. Is the proximal fit group or the persistent fit group, is there any groups that will benefit from the PFA of entero mitral line? And unfortunately, in both groups, there was no significant differences found either. And same findings were found for the first time ablation group as well as the radio ablation groups. So when we look a little bit closer to our efficacy endpoints, both radio frequency ablation and perceived ablation was very effective in terms of achieving the acute block. There was no zero initial procedure failure. However, it's a little bit noticeable that the radio frequency ablation group had higher number of percentage of people who had this recurrent atrial tachyardemia that was caught on the monitor, but it was fairly asymptomatic. Burden was extremely low and did not require further enterodemic therapy versus the PFA group who tends to be a little bit more coming back with the higher burdens. We had some patients who went back to the EP lab, so we had the chance to take a look at it. For the radio frequency ablation group, the three out of three patients had the reconnections across the entero mitral line and all of them had the mitral flutter that was confirmed with both entrainment as well as activation mapping. For the PFA group, the four out of six patients that went back to the EP lab had the reconnections across the entero mitral line and had the mitral flutter that was confirmed. One patient actually had the septal focal AT, and the last patient unfortunately came in for the ab nodal ablation with the pacing strategy as that was a patient's fourth radio ablation at the time. Well, something that we could not get was the amount of the burden. I think there has been a lot of discussion about the arrhythmic burden as the endpoints for the fib ablation. However, some of the outpatient cardiac monitoring doesn't really give you that information of what's the ATA fib burdens. So as a surrogate, we kind of wanted to look at the patients who actually needed further entero rhythmic management. People who needed either go on a class one or class three medications after the blanking period or people who needed either cardioversions or ablations. And when we compare this group with a little bit modified efficacy, it seems like the PFA group does a little bit worse compared to the radiofrequency ablation group with the log-rank p-value of 0.016. Looking at the safety endpoints, both procedure of PFA and radiofrequency ablation were pretty safe. So the composite endpoint, there was no difference. The radiofrequency ablation patients had four cases of people going into the pulmonary, having a pulmonary edema and volume overload requiring a further hospital stay for diuresis compared to zero case for the PFA. There was a slight higher AKI noticed for the PFA group compared to the radiofrequency ablation, but none of them actually went into the further deterioration of their lunar function and they all recovered. Limitations, this is a single set study, single center study with every case is performed with the electroanatomic mapping and ice. It's an observational study, so there are biases that comes with it. We did not have a continuous monitoring, so there are episodes that we could have missed. There was no standard ablation protocol for everyone and this only applies to the one PFA catheter. So in conclusion, the intramitral line ablation using a five-spline multi-electrode pulse field ablation catheter achieved a high acute conduction block success rate. However, this approach did not demonstrate the improved long-term lesion durability compared to the radiofrequency ablation. Thank you very much. Thank you very much. I don't see any questions on the group, but interesting that the PFA did not seem more effective than radiofrequency in the mitral isthmus. Do you think that's maybe because the mitral isthmus tends to have thicker tissue and the PFA may not give you the depth that you can achieve with RF? I think that could be. I mean, the mitral isthmus has very unique characteristics with a lot of epicardial connections. Less for the intramitral line where when we do the lateral mitral lines, for say, oftentimes we have to go into the coronary sinus and ablate. When we're doing a radiofrequency ablation with the venom marshal, we oftentimes have to ablate away from the endocardium into the epicardial space, really telling us that there are a lot of connections outside the epicardial space. And we know by studies that the PFA does not really provide better depth compared to the RF unless it's combined with the both. So it's not surprising that this was not giving a better result. However, I think there's a lot of future room to grow in terms of having better waveforms to find out for the intramitral lines as well as the more standardized protocol of how much doses in each area that we can give. Excellent. Thank you. So, last speaker, we have Robert Curley to speak about clinical outcomes of patients with mitral isthmus-dependent flutter undergoing anterior and posterior ablation. Thank you. Morning, everyone. My name is Robert Curley. I'm an EP fellow at the Brigham and Women's Hospital. I have nothing relevant to disclose. So, as I say, I'm an EP fellow here at Brigham and Women's Hospital. I'm an Irishman, and I'm talking about some of our data combined with our Irish data and some data from here in the U.S. Our clinical question is looking at mitral isthmus line using the PFA system but anterior versus a posterolateral line and our experience with it. So, pulse field ablation in AFib, it's kind of transformed our clinical practice in atrial fibrillation. It's got a lot of data behind pulmonary vein isolation, some of which has already been outlined by some of the previous speakers. We have evidence up to the level of randomized control trials for PVI. We know it's clinically efficacious. We know it's safe. For the posterior wall, we know it's safe, but some of what's been outlined by Dr. Marta Larenta-Ross, its clinical efficacy is maybe still a little bit dubious and still not sure if it has the same, it doesn't have the same clinical benefit as pulmonary vein isolation. But it does seem to be very safe, particularly with regard to the esophagus. But there's quite limited data with regard to linear ablation, but most of that focusing on CTI line and a lot of the data and clinical studies looking at nitroglycerin to prevent coronary vasospasm. So, in terms of previous data, there is this data from the Bordeaux group looking at patients with persistent atrial fibrillation, 45 patients in total, looking at acute procedural success, 45 patients they were able to achieve acute bidirectional block in 100% of cases. And of the 45, 2 patients had coronary vasospasm, both of which reversed with intravenous nitroglycerin, it was reversible, it didn't require coronary intervention. And as you can see here from the x-ray, all of these were posterolateral lines and most of the data that is published on mitralismosin is generally looking at posterolateral lines as opposed to the anterior. Typically ablating in the flower position with the pentaspline system. This is a multi-center registry, it was 47 patients in total. It was the pentaspline PFA mapping system, or PFA ablation system in all cases. Whether you chose anterior versus a posterolateral line was at the operator's discretion. The median follow-up that we had was 10 months. We didn't necessarily have a protocol because it was off across three different sites, but in all cases there was a vasopressor pretreatment with phenylephrine, either 100 to 300 microgram boluses, and then an initial nitroglycerin bolus of 2 to 3 milligrams into the left atrium and it was at the discretion of the operator if he did further boluses after that, waiting roughly one minute or so before providing or going towards mitralismosin ablation. The anterior approach was either in the flower position with the pentaspline system going from the annulus, if it was anterior, back to either the posterior wall isolation site or the right superior pulmonary vein, and the posterolateral approach from the left inferior pulmonary vein to the mitral annulus. And again, the decision to do one or the other was at the discretion of the operator using nitroglycerin in all cases. This is our results. So baseline characteristics, similar population to what we've seen from the previous speakers, all roughly around 70 years of age, predominantly male. There was a statistically significant difference between the anterior and posterolateral with more males in the posterolateral isthmus size, but small numbers. So as to the relevance of that, more dubious. Persistent atrial fibrillation in 70% of cases, mild to moderately dilated left atriums, as you might expect, and at least 50% of the cases had a previous AF ablation. And child VASC scores roughly in around the 3 or so range. Acute bidirectional block was achieved in 46 out of 47 patients. One patient, we couldn't achieve bidirectional block with the PFA catheter and had to switch to an RF catheter, and we were able to achieve bidirectional block at that stage. As I say, our follow-up was 10 months, and we had a 32.6% recurrence rate. It was a predominantly persistent AFib cohort, and 64% recurred with AFib, and nearly 30% with atypical atrial flutter, and 7% with focal AT. So roughly 32.6% recurrence rate in total. So as to our question for this cohort, what's the difference between a posterolateral and an anterior line? In terms of arrhythmia recurrence, there isn't one. You can see they follow a very similar trajectory across the follow-up time period with no real clinical difference, or at least in terms of atrial arrhythmia recurrence, between posterolateral and anterior lines. One thing we did notice was that the anterior lines took significantly longer in terms of procedural time compared to the posterolateral lines. I suppose in some respects that's to do with you have to apply more lesions for the distance. But when we looked into reasons, fluoroscopic time was similar. 3D mapping was done in 100% of cases. In the European Center, we do do PFA without 3D mapping, but when we knew our PVI+, mapping was used in all cases. ORF was used in only one case, which was the posterolateral line. The majority were the 31-millimeter catheter. And post-PVI, obviously done in 100% of cases, and posterior wall in most cases, but not 5 of the anterior approach. Looking into reasons as to why did the anterior line take more time, first past isolation, no significant difference, but was lower in the anterior line compared to the posterolateral ablation. And in terms of PFA applications, there was significantly more applications performed in the anterior line group compared to the posterolateral line group. So performing more applications, perhaps a trend towards needing to perform more applications to get block, which may drive the reason that the anterior line took a little bit longer. In terms of our complications, we only had one, which was one cardiac tamponade in a patient that required a drain. And funnily enough, it was in the patient that we had to switch to an ORF catheter, was the patient that got the tamponade. CTR line was also performed in that case, as well as a mitral isthmus line. So unclear as to whether the mitral isthmus line was the reason for that or whether it was bystander. Looking at the other available safety data, I suppose some of the concern with regard to saying that we should just do posterolateral mitral isthmus lines is the vasospasm issue. Here from the Hamburg group, Dr. Gunrardin, showing this is the PFA catheter in the posterolateral position. The CS kind of demarcates where the PFA catheter was. When they came on ablation, they got inferior ST elevation. You can see here in the red line that there's coronary vasospasm. This was in a patient that actually had an instant resynosis of the RCA, and coming on ablation to the left circumflex caused transient vasospasm, which led to the inferior ST elevation. So likely it was collateralizing from an instant resynosis of the RCA. The patient went on to have a PCI to the RCA the following day. This is from Dr. Vivek Reddy's group out of New York in the Czech Republic. This is focusing on CTI ablation, but the bolus strategy of giving a vasopressor and then giving nitroglycerin with multiple boluses in the minutes thereafter significantly reduces the amount of severe stenosis that we see in CTI block, which is what we employed for mitral isthmus block in this case. Then again looking at Dr. Reddy's group, this is looking at whether you perform a more superior or inferior line. Superior line here, you can see the yellow causing coronary vasospasm to the left circumflex, and another patient, a more inferior line, slightly smaller left circumflex, to be fair to the patient, but no vasospasm. In the nine patients that underwent the more superior line, you got coronary vasospasm in 60% of those, and then the inferior group, it was zero. Then also from this graph, it doesn't on the figure outline exactly what the graphs mean, but the dark blue is looking at severe stenosis in the time taken for recovery. The blue is the PFA group, and then the orange are the ones who had ORF initially and then switched to PFA, and then this is the ORF group, just showing that you get little to no vasospasm with ORF, and with PFA obviously significantly more, which is something that we're aware of. So in terms of conclusions, PFA, it's safe to perform on the mitralismus line. We get similar outcomes in terms of atrial arrhythmias between anterior and posterolateral lines. We did appreciate longer procedural times with the anterior approach compared to the posterolateral approach, and at least in our cohort, we didn't get any incidences of clinically relevant coronary vasospasm with the posterolateral approach. We didn't shoot angiograms for each case, so we may well have gotten some subclinical vasospasm, but we didn't see any evidence of clinically relevant vasospasm using the nitroglycerin approach. Thank you very much. I'll take any questions. Excellent. Thank you very much. I don't see any questions in the chat. Is there one here? I'd like to ask you a question regarding the number of applications you have shown. Was the number of applications only for mitralismus, or was the total number of applications for PVI-ismus? And the second question, did you have any waiting time? After the last application, did you wait like it was done after CTI, or is it only acute effect? Yes, so the total number of applications was for the case, so including posterior wall, PVI. This was a registry data, so some of the patients would have had previous fibriblation and would have had their veins done, and mapping, you may not necessarily need to have applied PFA applications in that case. So it was incorporating all of the applications performed within the case. As to the waiting period, it varied between different protocols, but the shortest waiting period would have been at least 10 minutes post-fibrillation for checking bidirectional block. And how they checked block varied a little bit, again, depending on the operator. Some using the far wave to go into the left atrial appendage and looking for a change in CS activation, with some people looking at differential pacing, particularly if they did an anterior line, going further back and looking at distance and timing. Excellent, thank you. So thanks to all of you for attending, to all the presenters. A very interesting session on PFA for the posterior wall and the mitralismus, one with a novel PFA technology, the others with the pentaspline. Seems like the posterior wall effect is durable with this technology, the mitralismus is feasible with greater occurrences. It's going to be an exciting field to see with different recipes of PFA, bipolar, unipolar, dual energy types combinations, what we can see. Still an open question as to the clinical benefits of these additional lesion sets, and future studies will tell. Thanks everyone. Enjoy the meeting.

pulse field ablation

PFA

atrial fibrillation

pulmonary vein isolation

mitral isthmus

myocardial selectivity

radiofrequency ablation

clinical outcomes

lesion durability

electrophysiological procedures