Dr. Gopi Dandamudi discusses the increasing use of His Bundle Pacing (HBP) and Left Bundle Branch Area Pacing (LBBAP) in clinical practice and presents available clinical outcomes data.
Back to Symposium Page » Welcome back everybody. To the late morning session. We're gonna we're gonna focus continuing here on cardiac arrhythmias and some device therapy associated with treating cardiac arrhythmias. Just have a couple of announcements um in terms of the live streaming streaming, make sure that all of your other internet connections are shut down just so it doesn't interfere with the broadcast. All participants will be muted during the presentation. So if you have a question, there's a button entitled to ask a question and we'll feel those questions and and on how the day goes. We may submit those questions right at the end of presentations or hold them till the end. Um See what else I need to. If your video, if your video feed freezes for any reason, just refresh your browser and that may bring it back online for you. You have to thank the Heart Favorite Society of America for co sponsoring this presentation. That's a big partnership that we appreciate. 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He's joining us from Virginia mason in the Franciscan health system in the pacific northwest. And I'm gonna talk to us about an exciting area of advancement in all right Into Cardiac implantable devices for for heart failure and bradycardia. Gold has been an innovator in this field, hasn't been involved for greater than 10 years. So he's a good person to get an update from. Thank you. Thank you. Thank you to all the organizers for this kind invitation get started here. These are my disclosures. So I like to always start out by presenting probably two of my favorite cases just to give you an idea of how his bundle pacing. How do I use it clinically? And what are the extreme case results when you get really good outcomes from them? So this is a 19 year old kid with history of congenital heart block. First diagnosed at age six When he turned 17 or so, he started seeing a cardiologist. He had been complaining about some mild symptoms of fatigue. So it felt that it wasn't inappropriate at that point to uh go ahead and undergo a pacemaker implantation. So he had underwent a traditional pacemaker at age 19. Unfortunately, this kid for two months was bouncing around emergency rooms in indiana until he finally presented one day in florida, heart failure and multi system organ failure. At that time, they diagnosed him with bi ventricular failure, cardiac failure and then he was urgently transferred to our institution for Mechanical support, potentially even transplantation. His FS 14%. And this is his paste QRS. When he presented, you can see bizarre wide QRS. Complex about 200 milliseconds. And some of this is also because it was underlying cardiomyopathy. You're going to get some intrinsic conduction delay as well. And before you underwent the procedure are actually a heart failure dockside a long discussion. We weren't sure we thought maybe pacing induced cardiomyopathy but it's a pretty extreme form of it. After discussions, it was decided that maybe we should attempt at least cardiac re synchronization therapy. And they knew that I was doing his bundle facing. So he said, lots of templates bundle facing. Mind you that for one week before the procedure, he was multiple pressures and finally reaching down to two pressers and on ivy diuretics. At the time of this procedure this is 10 minutes into the procedure. So here's a kid who was born with complete heart block, never had a V synchrony. And within 10 minutes we can actually pace the conduction system and recruit his own intrinsic conduction. And what's more impressive is within four days you can see QRS is actually narrowing. His left atrial size is actually diminishing and his cures is reduced 108 milliseconds. So this kid walks out of the hospital seven days later after he instituted this bundle facing an oral met. So this was transforming our heart failure. Guys are totally ecstatic about it, saying that, wow, this is the greatest thing since sliced bread in this particular case. So I went back and looked at this particular case to say what exactly happened during this period of time. Once we started this bundle pacing and just looking at his labs and his metabolic profile. Well you can appreciate here is his these are the red values are the day his funnel pacing was initiated. So this is his BNP on that day and you could see it precipitously drops within two days. He's off all these pressers and actually off his diuretics can see what happens to his platelet counts, they're sequestered. And once you start his public facing actually normalizes, this is his total billy Rubin that the pocket was totally Jon dissed when I was actually doing the his lead and you can see uh trending towards normalization and can see his entire metaphor metabolic profile totally transformed. Only thing different we did was actually initiate his fungal pacing and we actually started taking off all the other pharma co therapies that he was on. So incredible case. Probably by far my best case I've ever had with his family facing or any kind of pacing. Another interesting case, uh a post transplant cardiomyopathy patients, a 70 year old with the history of uh uh skinny cardamom. But he had an L. A. VOD followed by a transplant eight years prior to presentation And then he developed heart failure. And of course the first thing we always suspect his rejection. So he underwent under my cardio biopsy very mild rejection but it was unclear at that time. So underwent aggressive therapy with the immuno suppressants, repeated biopsy, no rejection. But six months later in the afternoon improved. So as they're actually afford for E. P. For IC. Consideration. So going back we're just looking through his sgs and six months prior to presentation with heart failure, he actually developed the left branch block. So interesting uh post transplantation is usually developed right bundle branch blocks because we biopsy them all the time. But it's rare to see actual left bundle branch block. So this is the donor heart. Uh And then having a left on a bench uh in this case. So we talked about it by the by now we've all seen uh plenty of cases with left on a branch block and just cardiomyopathy. That was my suspicion from the get go talk to him about conduction system facing. And this is literally probably 15 minutes since the procedure can recruit the conduction system and actually normalize the left on a ranch walk and I'll explain to you how that's possible in the subsequent slides And follow up is EF actually improved to 42 in a short period of time and totally normalized. So we actually published this as first case of a donor heart developing left Bundle branch block media to car. Democracy actually reversed with this model basing. So we are all are familiar with ventricular pacing techniques. Most common try tested no matter what the data is for our vehicle basing. And we know that vast majority of people worldwide get this form of facing and do just fine. But however, there is a substantial portion And most literature, if you look at it probably accounts for about maybe 15 of patients or so. This is similar to when you see PVC news cardiomyopathy where we say greater than 15 burden, 20 burden. Canadian result potentially in cardiomyopathy. We have a news cardiomyopathy, which happens to be about 15-20 of patients. Somehow all these Tend to fit that mold of this 15-20 of patients. Um, and what about RV septal facing people have looked at our reception facing as another alternative? You're facing closer to the conduction system. Maybe that's better than facing into my card um, itself. And of course we have diverticular facing with multiple data on it, especially in love, fundamental block patients and what morbidity and mortality benefits related to it. If you look at meta analysis of all pacemaker trials, especially the original pacemaker trials, there was a trend towards not only a trend actually statistical significance, showing that if you do RV pacing, no matter what in any patient who gets RV pacing, they have an increased risk for atrial fibrillation, development of atrial fibrillation as well as potentially stroke and that's unknown phenomenon in in patient. If you look at specifically the degree of pacing, ventricular pacing, this is from most trial, one of the landmark trials and pacemakers specifically looking at the percentage of ventricular pacing that people undergo once you're implanted to hire the degree of ventricular pacing. The higher the likelihood you develop heart failure and the higher the likelihood to develop atrial fibrillation and there's actually association that the higher the degree, the higher the likelihood you can develop uh other co morbid conditions. So along the same theory, people started asking, what about heart? People with reduced ejection fraction, They reduce stroke volumes. Cardiac output is low. Maybe if we paste them we can increase the stroke volumes. Maybe they'll have better outcomes. So this was again a landmark trial and I. C. D. S. Looking at what if he pays people who have low eFS and they get prophylactic I. C. D. S. But we actually paste them. This is with D. D. D. R. 70 beats per minute of four spacing, both nature and in the ventricle in this case versus V. V. I. 40. And what they found was the hired again the degree of pacing the ventricle. The worst the outcomes were you can see the difference between outcomes of uh four spacing versus uh intrinsic conduction. So all along those lines, all the industry, all the companies industry developed all these pacing algorithms so I always laugh with pacing. Uh Initially when the indications were there we put pacemakers to pace people. Now we put pacemakers and try to prevent the pacemaker from pacing. So something is not right with what we are logic of putting pacemakers and people and minimizing how much facing we can do by promoting intrinsic conduction. Uh There was also along the lines of thinking about what about subtle pacing and this is probably this one study put things to rest. This was the protect a study done in europe Australia, new Zealand About 240 patients were randomized to do either RV typical pacing. RV high septal facing And in those patients have to require significant particular facing and had to have ejection fractions less than 50 greater than 50%. What they found was is no hard endpoint outcomes. That that there was difference between the two, whether it be heart failure or mortality or even a f all it did was add more procedure time and increase Flora Skopje times. So what about by ventricular pacing? So along the lines? Clearly by now we have tons of data, especially in the advanced heart failure population, especially with left corner, branch block, wide, left corner bench block, that it is superior to regular pacing. What about in patients besides that population? So ef between 35 to 50% or other educations for pacing, it has to be better by the same logic. And there were two large trials walk HF and bio pace trial block H. F. I think most of you may have heard of. It was essentially an interesting trial that combined a structural in point. This is echo parameters and added it along with the clinical endpoints heart failure and mortality. And this is the first of all. The entire results were actually statistically significant results. The primary outcomes were driven by structural changes, not by heart outcomes. So this was purely by lV systolic volume in exchanges. But even though you see that clearly there's separation between the two You can appreciate within by ventricular pacing within the first six months or so, 30 of patients still had met the primary endpoint, whatever that may be in this case, probably structural changes. Yes, admits hiring the right ventricular pacing about 45%. But you can see that even the slope of these that both patients don't do that well with by vey casing. In this patient population, one may be better than the other. But ultimately, if you're looking at it from a population perspective, both of them are not the ideal outcomes. If you look at specifically heart failure, urgent visits again with bi ventricular pacing versus right ventricular basic. Yes, there is early separation, but if you look at the slope of it, both of them are declining at the same rate thereafter. So it's not the ideal form, maybe it's better than are vey casing, but it's not the end All be all interestingly. There was a much larger trial called the bypass trial that was done in europe. Unfortunately, never got published. It was only in the abstract form and probably you can figure out why it wasn't published based on the results. But this was again, ventricular pacing indications any eF with prolonged PR interval and in patients in much bigger trial to me three times the size of blockade Jeff With preserved if there was no difference between the two and even slightly reduced to you if you can see the mean of 41%,, because again, there is no different statistical difference, significant difference between the two whether you do by v pacing or right ventricular pacing. So the jury is still out in all this patient population. What is the right approach to paste them? And if you look at all the facts about CRT two dates, unless you have advanced heart failure, Class three, Class four and white left bundle branch block, typical left bundle branch blocks greater than 150 milliseconds, all other forms of cardiomyopathy. These kiosks, durations and all that is really not the strongest evidence. And I think the most recent era guidelines coming out actually appointed to that fact, again saying that there is really no clear evidence for patients beyond what we do traditionally with the White Love Connor branch of our patients. So clearly there has to be a better answer for us in terms of pacing in terms of finding other solutions that are slightly better or better than these kinds of outcomes. So why his bundle pacing? So here's a nice example of body surface mapping. This is essentially a 500 lead scg system that you wear like a vest and it records and you can see intrinsic conduction here. And when you're recording the activation patterns, the right ventricle and left ventricle, you can see completely homogeneous activation of both the right ventricle and the left ventricle. That's because we all have his fucking the system. And the best way to look at it and explain to people is when we're all born, we have a QRS duration of probably 50 60 milliseconds, Maybe at most. We all die in majority of us the curious intervals about 102 110 milliseconds That tells you how conserved to our restorations are over the lifespan of 90 years. That's because his parking system conducts electrical electricity. If you uh simplify four times fashion in the mind cardio. So there's something about the historical in the system, the way the cardiac muscle gets activated intrinsically is so much more superior to any other forms of activation. So when you do selective Istanbul facing group, basically stimulating the conduction system directly without stimulating anything else. No. Meyer cardio or anything else. Just in isolation this bundle and you can see it's identical in how the activation patterns are. When you do non selective ist bundle facing are actually facing. Not only the conduction system but the local myocardial. You don't have control where you put the lead, what myocardial is surrounding it. So when you're stimulated you get a little bit of septal activation of the my cardio. But you can see what happens to the L. V. Because the entire history of the system on the left side is being activated directly and stimulated. So it's continuously. If you look at all three of them, their homogeneous activations of the LV. When you talk about by v pacing, it's a totally different beast altogether. We're facing the RV endo cardio because the lead is inside the RV and we're facing the LV. Epic Ardian which is all the way on the outside. And that's not natural way of activation of the cardiac conduction system. But because of baseline curious is being really wide. And left bundle branch block, it makes sense that somehow fusing both these wave fronts will actually benefit electoral synchrony to some degree. And that's why it makes sense that these wide left bundle branch block patients respond better than the narrow QRS complexes. Because when you start facing the L. V. M. Pericardium, you get really bizarre white curious complexes. And this is an old concept. This is nothing new. This is back in the 70s that was described for the very first time about this idea. This concept of longitudinal dissociation. It's a little controversial whether it's entirely this mechanism or not. But the easiest way to understand this is if I am constructing a conduction system and I have an A. V. Node and I my bundle branch is to take a whole bunch of cables and I run them from the A. V. Note into the my cardigan take a whole bunch of cables and running from the A. V. Note to the left side. That's the left on a branch block are left on a branch and now I take all those cables and I wrap them up together. That's what happens in the common bundle. So this theory that left bundle, branch block exists in the periphery and the right bundle. Branch block exists in the periphery is not entirely true. A lot of these actually happened and within the proximal portions are the different portions of the common bundle. So that's why we can pace at that site where the block is are just even distal to it and actually recruit as you can see here The left on a branch block again. This is back in the 70s. This was all described however, as we know technology, we need technology to advance our science and this is a doctor dash book guy. Solo guy practicing out of Sayer pennsylvania designed the first study himself after talking to DR charlotte and how to do it Are to understand the pitfalls of it and published his first clinical experience in humans. 18 patients who had cardiomyopathy is chronic af underwent a v junction ablation and he was able to show that hey, this is feasible and can be done in clinical practice. Uh This is some of our data that we published that we've collected over the years. This is back at Geisinger where we had to cohort. These are not randomized trials. These are really prospect cohorts essentially kind of matched population, a lot of elderly population. So that kind of ended up being matched well together. So patients who understand either his bundle facing or by our RV pacing. I'm looking at the outcomes over time and the population cohort and you can see that there's uh his panel facing physiological facing tends to favor better compared to RV casing. And specifically, once you start getting into higher burden of ventricular facing, the higher the degree of ventricular facing, the higher the benefit. What test bundle basing compared to? Are we facing? Which we would expect if you thought that RV pacing causes the synchrony and cardiomyopathy. If you're not doing that with pacing in other forms, it should only improve that outcome. We also looked at this is pulled about five centers. We pulled our data together and failed by. These are non responders and also de nova patients like the one I showed you about transplant patient with CRT in this particular case, a pool group. Again these are all seasoned people have been doing this for quite some time. Success rates are close to 90%. But more importantly you can see what happens to this patient population. Again, these are failed by these non responders or even DeNoble CRT patients overall. You can preserve the native intrinsic cure restoration for the a vast majority these cases. Look at the significant difference in terms of left bundle branch block or bundle branch block in these cases, narrowing them and ventricular paced rhythm going from 100 and 77 225. And you can see overall improvement and ejection fraction in this entire cohort and improvement and functional class as well. Based on this, not just this but limited data. The data is strong enough for the heart rhythm society A. CcH A. To come up with guidelines to suggest it carries a two way indication and patients and that block HF bio paste kind of patient trials where between the f of 36 to 50% and who are frequently paste, you can actually do either his bundle facing or in lieu of by the pacing in that patient population and specifically A to B. Recommendation which is pretty weak but in the sense that it's using physiology as its background to say it makes sense. Any patient who has a V. Block at the time of indication for a permanent pacemaker can undergo his funnel facing. Uh there's a new kid on the block left on a branch area facing most of you. I'm sure I've heard of it. Uh this was actually described by Dr Wang from China back in 2017 2016 2017. And the whole concept of this is when we do his final pacing, were actually pacing in the proximal portions of the common bundle and sometimes a little bit distal portions. What if and some of the downsides of this panel facing is this area is encased within fibrous tissue. So sometimes when they're pacing thresholds are high and sometimes you can't even predict in the long run what the threshold is going to look like for the vast majority of time they're pretty stable. But it's still it leaves that doubt in your mind that will these last for long periods of time. The advantage of doing left on a branch area, pacing is going distantly into the mic Rd. Um Because the left bundle branch actually runs on the L. V. And a cardio side. At least some of the branches of it and actually screwing in the lead deep into the symptoms. So you can see here on a. On a. C. T. Um Look how deep the lead tip is. So this is actually on the RV side, penetrating through it through the septum getting to the LV. End of cardinal side. So the idea is to actually capture fibers, the left bundle branch fibers on the towards the el viento cardio side and engage them. He was a good example. This is a patient of mine with persistent left side fc. As we see, one of my partners attempted uh coronary sinus facing with cardiomyopathy and uh didn't work and I'll show you why you can see here how big this is. Gargantuan one. He tried multiple times, multiple efforts actually two times with different tools that didn't work and referred for his panel facing in this case. And in this particular case tried this public facing thresholds a little high the one to left bundle branch area facing. And as we're pacing the septum you can imagine pacing the RV side of things. You get a lot better branch block pattern because you're recruiting the right bundle branch fibers. But as you go to the septum further and further and further. Now you're starting to recruit the left bundle branch fibers directly. So that gives you a right bundle branch block pattern as you're facing. And you can see this is actually an ectopic beat as replacing the lead. It's irritating the tissue, especially the left border branch fibers. And you're seeing a spontaneous beats with white bundle branch block pattern, that's a good sign in college fixation beats the different terminology for it. But as we're advancing the lead and we're doing this once we start seeing this behavior, we can say with some confidence that we're actually engaging all foreign branch fibers. And in this case you can see how deep the lead is the lead. The sheaf which is against the septum ends all the way up here, near the back end of the proximal poll. So this measurement is about one centimeter deep. So this lead is penetrated through the septum one centimeter deep. Some of you may wonder hey, the septum itself is one centimeter 11.1 centimeters. How do you know? It's not perforating. Remember that these are not going directly perpendicular at 90 degrees to the septum. They actually are a little bit angled, so really the length of that it actually gets longer. And we're not actually penetrating the septum through the septum and coming out of the septum. And there are certain characteristics that we can look at to suggest whether we're going too far into towards the LV and myocardial side. Yeah. And in this particular case you can see once the conduction system is engaged on the left side. Got this incomplete right bundle branch block pattern and in this case you're actually pacing from both the so there's animal capture from the proximal poll as well. So you're actually engaging the right bundle conduction system along with the left bundle conduction system and that's why you can get it really narrow, curious complex. This is about 110 milliseconds or so. So what are our current limitations with all these? So we have limited sheets and leads for all anatomy types and all ages. So I always compare this with baby pacing. When baby facing first started, we had one unit polar lead, there were new in really sheets at that time and look where we are today. We have tons of sheets, different types of leads, Quadra polar leads, a fixation leads and so on. These tools that we're doing for conduction system facing were never meant for conduction system facing. These were meant for traditional facing. So you've learned to adapt the same tools and use them for this. So it's hard to look at the scope of this and what the future holds without actually having the right tools. Companies are slowly investing in this technology. So what we're seeing more and more as interest speaks, this is really driven by physicians worldwide for the interest in this. And also we have to design our devices to actually look at things differently traditionally right now. The way the sensing algorithms, pacing, algorithms capture, management algorithms, all of those are designed for typical myocardial capture, not for conduction system capture. So until we have those kinds of tools, it's really hard to say what is going to be the true success of this in the long run in a population, really large scale randomized trials. Really, it's hard, I can tell you personally, we've tried for a long time to try to get these trials going. There's a lot of competing interests within, within the technologies that are being developed. And there is a nurse here from companies to do large scale randomized trials. If you can get to a indications right now and we can use the current devices. Why should any company really invest in a large scale randomized trial at this point? So there's some roadblocks that we have to come over, come here to make this more viable in the long run as a procedure that all of us can do so in summary, uh these are becoming increasingly popular in clinical practice. Um I was just talking earlier to our panel that there is enough interest in it that pretty soon we're going to come up with a consensus guidelines from uh heart rhythm society to talk about these. Where are the indications for this, what what literature do we have to support these and so on. The success rates globally. If you look at it, if you combine all of these hispano facing branch area facing, it's probably around 80 to 90%. Um Obviously more skilled hands, it will be higher and less skilled hands. It's just a learning curve. Just like bobby pacing, longer term Malcolm's are definitely lacking. Still I think we have some good short term retrospective, some prospective data but we need really large cohorts to look at this outcome because pacing is a permanent thing that we do. It's not like an ablation procedure where your failure you can go back. This is something we're going to do once and we want it to work. Um Hopefully for the rest of their lives implant techniques and physiological observations continue to be refined for sure. We still don't even have fixed terminology that everybody accepts, especially for a left on a ranch area facing. And finally we need to really understand what didn't even left on a branch area facing, which is relatively new, different types of facing. We understand it much better for his bundle facing, but we clearly don't have a great understanding with left on a ranch area facing. And for those of you are interested in following this whole thing. You can follow us on twitter and don't this the highest uh where we try to put all the examples worldwide for as an education tool for people and to share their experiences. Thank you. Thank you. Go be excellent update. Um what would be you talked about this a little bit just before we came on, what would be, what would be your advice to for somebody who's thinking of getting into this, The data looks compelling. There's your case examples are dramatic, those are very compelling. Um I think a lot of people worry about lead, dislodge mints and threshold. So, so how would you advise getting into this space? Yeah. So one is, you have to be committed and have some time for it. You can't think that you're going to do the same amount of time putting in a micro and a traditional pacemaker because your first few cases you are going to struggle. It's going to take some time. So first always prepared going in that this is going to take longer than your traditional pacemaker. The second is a patient population is incredibly important. The first probably 25 cases I did or in patients with sinus node dysfunction. So I wasn't worried as much if thresholds went up or I didn't get the same, I didn't get good his final capture and so on. At least I didn't have to revise the lead and I felt better than at least a trillion is working fine. So I would start out slow do it in those kinds of patient population who are not dependent on ventricular facing. Get used to the idea of doing it. You have to set up your truck procedurally, you have to set it up properly. Post procedure. Follow up has to be done properly. So start slow. Pick the right patient population. Don't jump into complete heart block and left on a branch block patients as your get go. Unless you really have to do it as a salvage procedure and then slowly build yourself up. It will take time just like by vis that we did. This will take time. Okay. And then can you make, can you comment on the european heart rhythm societies recent decision regarding this? Right? Uh so just a lot of the press in the last couple of days era, they've been doing their annual meeting and some of these have come up in terms of the indications. So the Europeans and, and rightly so have questioned that even though there is mounting evidence, they're still not strong enough evidence to come out and and recommend that this should be an alternative to buy the facing. This should be exactly an alternative RV pacing. They do specifically say where you're not getting a good outcome. You can attempt this bundle facing and so on. But they didn't come out and and say that this should be the first mode of facing and everybody that you consider especially loved underground box or even complete heart block patients.