Hi, I'm Eric Prystowski. Welcome to another segment of EP on EP. We have a return guest because he always has something important to say, Dr. Ken Ellenbogen, who is the Kimmerling Professor of Cardiology at the Medical College of Virginia. Ken, welcome to the show again. Thanks, Eric. It's great to be with you in San Francisco at a great annual meeting. So you put the plug in because you're the abstract chair of the whole meeting, did you? Yeah, and it's just great to see all our friends and colleagues. Yeah, I agree with you. And you guys did a fabulous job. Thank you for shepherding through the meeting like this. So I know this is a topic that you don't like to talk about, but I'm going to bring in pacing. I'm just kidding. So I like to talk about this whole TAVR issue with pacing, but let me start with a quick vignette of a patient of mine literally a week ago. He's a gentleman that we ablated for AFib, I don't know, 15 years ago. Unfortunately, he's still staying in sinus, but he also had aortic stenosis, tracking him every year. Finally, it got to the point where I sent him to my valve specialist, put in a TAVR, and I got, I'm actually here at the meeting at this point, and they text me, Eric, I just want to let you know, so-and-so developed complete heart block. Now, he had a right bundle left axis for 15 years. We put a temporary wire in, and I said, oh, keep me in touch. And then the next morning they say he's still in heart block, we're putting in a pacemaker. So I guess the start of this is then, we're all sending people for TAVRs. Give us your feel of how we should figure out who this person, I mean, maybe you could say this person's a little more obvious, but who are the patients that we should really be worried about getting into trouble? So that's a great question, and the reason why it's so hard to come to a consensus on some of this is because any one center has only a relatively small number of patients. And there are no multi-center collaborative trials looking at, for sure, who are the most high-risk patients. Obviously, the patient you presented, someone who has a pre-existing right bundle branch block because the aortic valve goes into the septum, and that's where the conduction system lies. Patients who come in with some degree of heart block, first degree AV block, second degree AV block to begin with. The real difficult part is figuring out what you do with patients. So you presented a patient who went into complete heart block with the TAVR. Next morning, still in complete heart block, patient needs a pacemaker. But there are plenty of patients who will have transient heart block or some EKG changes, and then it becomes what's the best thing to do for that patient. That's the segue for me to my next question. We know that there are people ahead of time you told us that we have to be pretty careful about. Let's say this patient of mine did not have heart block, so let's take him a different route. So he gets it done. We're not, at our center, keeping people for days in the hospital, so we're going to send him out probably, and if we do, I mean, is this the person we should watch an extra day, or do we send him home with some kind of a recorder? What do you recommend there? So that's the gray area. Let me give you an overview of what sort of the consensus is among experts who have looked at this area and reviewed the literature. There have been several documents along that line of review of the literature, come up with recommendations. One, which we did in 2019, published in the Journal of the American College of Cardiology, and then in 2021, another sort of expert's consensus. So if a patient has a TAVR and they develop transient heart block, then you need to watch that patient carefully for a minimum of 48 hours. Or if they develop a change in their QRS of 10% or greater, or a change in their PR interval. Now talking to somebody who knows, is a guru in autonomics, change in PR interval, what does that mean? That depends on the heart rate, on the autonomic tone. So some people have defined it as a 20 millisecond increase in PR interval. So you use a magnifying glass to measure? That's a pretty tight measurement. And of course it depends on the heart rate. So let me stop you saying. So let's say their QRS is narrow and they develop a 40 millisecond change, but the QRS is totally normal. Is that the same as somebody who has a bundle? We don't know. We simply don't know. So it's just a precaution nonetheless. So if somebody develops a bundle or their PR interval prolongs by 40 milliseconds, the recommendations are that they stay in the hospital for a minimum of 48 hours or longer for telemetry. And then let's say nothing else happens in those two days. We always want to get these patients out of the hospital. The guideline recommendations are that those patients should get some sort of patch monitor for a minimum of two weeks, generally one month, and there be a system set up so they're being watched closely. I don't quite know exactly what they mean by that, but we all know those patients can have sudden onset of heart block and really a profound brady arrhythmia pass out. The thought being that they need to be alerted that they're at increased risk of heart block and have a very low threshold for getting into the hospital as quickly as possible. So not talking trade names, but I think what you're really saying is make sure that the listeners understand is that we're not talking about putting an event recorder on that patient hits a button. They have to be on some system that's being watched. Absolutely. That's what you're saying. Absolutely. Some sort of, without using any trademark names, some sort of a real time telemetry system for a minimum of two weeks is what's in the recommendations. But these, as you point out, affect a large number of patients. So new bundle branch block. So if they didn't have a bundle branch block, they come out with a left bundle branch block. They just bought themselves two extra days in the hospital for telemetry. They have a PRNF of 220, they come out and it's 250, same thing. Any sort of progression of the PRNF or QRS widening, and QRS widening here, 10% or greater is what was used in this consensus document. So let's talk about a QRS of 80 milliseconds, and you're going to tell me you can measure eight milliseconds? I mean, so some of these are kind of goofy, right? I understand where you're going with this, and I understand the physiology behind it, but some things are just measurement errors. Well, they were in the standard deviation. And then one other issue that comes up because we all do EP studies is what's the role of an EP study in terms of risk stratifying them? Yeah. Tell me about that. Is that worth it? Well, we thought that it might be useful pacing the HM, looking at a wanky box cycle length, but in the latest advisory, nothing about an EP study. Now, obviously you can say, I'm really worried about this patient, and I think if you're really worried about a patient, they have new bundle branch block or bifascicular block, and you're really concerned about hysperkinesis disease, then you put a hys bundle catheter in their HVs, 90 or 100 milliseconds, and they've bought a pacemaker, and you don't have to worry about them. But it is not required, and it should be case by case. All right. So let's go back to my patient, since you've filled us in on what to do. Now, we know in my patient, block stayed there 24 hours, and so he got a pacemaker. Now again, so block goes away. Now he started with a right bundle left axis and a prolonged PR for 15 years, okay? I don't know. So let's say I watch him for another day, right? Because the issue would be 48 hours, and he's still in normal rhythm. But I know for a fact from following some of these people that five, six, seven days later they can develop block. Oh, no question about it. I don't know. I'm anxious on that patient. So the recommendation would be send him home after 48 hours, if he's still in one-to-one. So a patient has transient heart block but recovers, the recommendation is you monitor him for a minimum of two days, and then you're right. You send him home, cross your fingers, monitoring. I've had one of those patients pass out at home with complete block. I, too. You've had two. I, too. So I don't know. It makes me a little worried, to be honest, if they have complete heart block. Right. Well, we need some way of better risk stratifying those patients, as you point out. The risk is in the single digits, but again, if it's your patient and they pass out and break their hip, that's a trap. They feel terrible. Yeah, of course. After they've had this brand new therapy and they're feeling good. So let's go now to therapy for these patients who need a pacemaker. So I know that you have no experience in CSP. No, I'm teasing you. Just the last 67 years. So I know in a sense I'm asking the, what do they say, the wolf to guard the hens here with my comment, but I'm going to ask it anyway. What is the preferred pacemaker in this person with who, because of a mechanical issue, has developed complete block or high grade block or something? What are you doing? Which kind of pacemaker? So it's interesting. If you look at the literature on surgical aortic valve replacement or SAVAR from 10 or 15 years ago, you'll find that, and of course the same constraints, that is you have a patient in the hospital, they just had their aortic valve replaced. They're in a heart block three days, four days later, and they're ready to go home. So what are you going to do? You put a pacemaker in them and then they come back six months, 12 months later and you see how much they pace and it's like 1% and you're like, oh my gosh, if I was just more patient, if I kept him here for two or three weeks, but that's the fact of the matter. So that has led to a variety of, I'm absolutely fascinated by the different strategies. In my shop, in my place, all these patients get conduction system pacers. And I think it's fair to say that most of these patients get dual chamber pacemakers, but some of these patients, they probably figure they're ultimately going to have a low burden of ventricular pacing. They'll be fine with a single chamber pacer. And in fact, I know there are some centers several years ago before micro AV, before a dual chamber, leave this pacemaker came out. There are some centers that put leave this pacemakers in before there's a possibility to get AV synchrony. So I think the point is that our preference is dual chamber pacing and the ventricular lead should go in the interventricular septum. But there are people who will do leave this pacing and the patients for the most part do very well. And there's no different. I know they have this new piece of hardware in there. It doesn't affect the success rates or anything like that. I mean, is it like a native problem? That's what I was kind of getting at because it's sort of a manmade problem, but you find that you still get good results. You still get very good results. And in fact, we've looked at conduction system pacing and valve patients and they do very well. Ken, I'm going to stop you at this point because it's been great as always. And again, thank you very much. I didn't tell the listeners, we are at the 2022 Heart Rhythm Society Annual Meetings here in San Francisco. I didn't use that as my promo. And thank you for doing a great job with the meeting and we look forward to you being chair of it next year in New Orleans. Thank you, Ken. Big easy. Thank you.

transcatheter aortic valve replacement

TAVR

pacing

heart block

pacemaker