Melanie Cole, MS (Host): Welcome to Meaningful Medicine, a Novant Health podcast, bringing you access to leading doctors who answer questions they wish you would ask. From routine care to rare conditions, our physicians offer tips to navigate medical decisions and build a healthier future.

I'm Melanie Cole. And today, we're learning about the heart and specifically pacemakers with my guest, Dr. George Waits. He's a cardiologist with Novant Health. Dr. Waits, thank you so much for joining us today. Please start by telling us a little bit about what a pacemaker is and how it works. What's it doing in the heart?

George Waits, MD: Well, Melanie, thank you for having me on. It's a pleasure to be with you, and I'm more than happy to discuss pacemaker therapy, which is a big part of what we offer in the Cardiovascular Institute here at Novant. So, a pacemaker is a device that we offer to particular patients primarily with problems with a slow heart rate, and the symptoms that come with that.

We can address those problems in many cases by implanting a pacemaker, which is a device that is implanted to guarantee that a heart rate does not fall below a level that we set. And in many cases, I'm pleased to share that we're able to address patients' symptoms and give them the heart rate that they need to do what they need to do.

Melanie Cole, MS: Thank you for that. So, what kinds of heart rhythm conditions typically lead to you to recommend a pacemaker in the first place? So, you mentioned that they help keep the pace of the heart so that it doesn't get too low. Tell us a little bit about some of these disorders.

George Waits, MD: Absolutely. So, I would say that a large population of people that we treat suffer from some type of electrical rhythm disorder of their heart. And what I'm talking about is either the impulse that forms the heartbeat is failing to initiate, and we call that sick sinus syndrome, the inability to generate an adequate heart rate to supply the body's needs, or if their heart rate is initiating properly, sometimes there's a failure of that heart rhythm to conduct along the conduction system of the heart. Commonly, we refer to a condition called heart block, or sometimes it's a complete heart block, or sometimes it's a high-grade heart block, but some failure of conduction between the top chambers of the heart, the atria, and the bottom chambers, the ventricles. So, whether the heart doesn't start well or whether it fails to conduct well, those are the most common reasons why patients might feel symptoms, you know, fatigue, low energy levels, in some cases,you know, even passing out. You know, some more alarming symptoms can be due to these disorders. And, in many cases, we identify, we implant the pacemaker, and we're able to treat these common conditions.

Melanie Cole, MS: Thank you for telling us also about some of those symptoms, because that's an important thing for patients to really know and be able to recognize. Are there different types of pacemakers?

George Waits, MD: Absolutely. Yes, there are different types of pacemakers, and we try to tailor the choice of pacemakers towards what that specific patient is needing. The very, you know, initial models, you know, going back to the late '50s when the first pacemakers were implanted were based on what is called a transvenous or lead-based system.

And that is that we use wires that are connected and wires that run through the course of the body's veins, usually from the shoulder into the heart. And depending on the particular application, that patient may require one, two, or in some cases even three wires to appropriately restore the proper conduction of the heart. And that system, again, that goes back to the '50s, is still frequently used today. I would still consider it to be, in most cases, the standard of care for most patients. But technology has advanced.

And with innovation, there are other types of pacemakers as well. We are now positioning those leads in different places that are able to pace the heart in a way that is more physiologic, that is we're able to pace the body's own wiring directly rather than just pacing the excitable muscle. And in certain cases, there are pacemakers that require no leads whatsoever, which I can go into further. So in certain cases, the leadless pacemakers are chosen in certain scenarios.

Melanie Cole, MS: Well then, let's expand on that a little bit, Dr. Waits. What are the advantages of a leadless pacemaker for patients compared with those older wired systems? Tell us a little bit about patient selection and what are the advantages?

George Waits, MD: Leadless pacemakers certainly raised our interest and excitement when early models have been available for some time now, probably close to 10, 15 years now. But just, you know, recently, we've been implanting, in some cases, two-chamber pacemaking systems.

That is two separate components where we take pacemakers that are smaller than a AAA battery, but that themselves have battery lives sometimes approaching 10 years. Occasionally, we will use even two components so that to restore or maintain communication between more than one chamber of the heart.

And so, I consider that type of therapy for patients who require a pacemaker, but have particular reason, where they might benefit from a leadless system. So, I think of patients, one example would be patients who require dialysis because of advanced kidney disease. In those patients, we really want, as best we can, to spare their vasculature. And so, putting in a wire in those patients sometimes can lead to, you know, adverse effects on that vein that they would otherwise benefit from using for dialysis.

Other patients would be those who have a high risk of infection. So, it's often, you know, the case if you've had an infection before. Any infection that is serious enough to affect the bloodstream can involve those wires that are in the heart or even the pulse generator, which is implanted, you know, beneath the skin near the shoulder. If those areas get infected, that can create a serious clinical scenario. So, I know that if patients, you know, have had infection or are at high risk of having that, then that can be a reason to reach for the leadless pacemaker first. And it's important to say too that we don't offer that to everyone. And the reason I say that goes back to what I referred to before, is that it all goes to where exactly the impulse of the pacing is happening.

And under the current leadless pacing design, those leadless pacemakers are pacing the heart muscle. And so, the way that the heart is activated is not quite as physiologic as when we're able to pace. There are specialized conduction fibers in the heart. And if we're able to pace those directly, we often see more of a benefit. And I would describe that as a current limitation of the current leadless pacemaker systems. There are efforts underway to allow them to pace deeper into the specialized fibers of the heart. And I think when that becomes feasible, then yes, I think that very well could shift our focus towards maybe implanting those more as a first-line therapy.

But as it stands now, I reserve that for patients with specific interests in avoiding, you know, those lead and what we describe as pocket-related complications of the standard model. But that's how I would characterize it.

Melanie Cole, MS: Well, Dr. Waits, while you're telling us about the ideal candidate for these leadless pacemakers and the patients that might still require the traditional kind, are we looking at the age of the patient or the BMI? Are there other factors that you take into consideration?

George Waits, MD: I do. We always want to account for demographics and medical history to make the best choice. You know, when it comes to age, I would say that, with the very elderly, you know, I do give a little more thought to leadless pacing in certain context.

And to explain that, I would say that we need to just give a little further background, which is that, again, when I make that distinction between pacing heart muscle versus pacing the conduction system, the reason we know that that's important is that what we've learned in the decades of the old standard of just pacing the heart muscle alone in no particular location, there were a subset of patients who would develop heart failure. Now, it might take many years, but there is a described phenomena where certain patients may develop heart failure just by the way that their hearts are being paced. And of course, that's not the intention of the therapy. And it doesn't happen often, but it's enough that many of us are now changing our approach to trying to pace the conduction system fibers as much as we can.

And so, for that reason, I'd say because that phenomena is long-term, if I, you know, am under the care of someone who's very elderly and, you know, they're concerned about maybe they've got some bleeding risk or infection risk, that they've developed, I do think a lead-less pacemaker, you know, after a full discussion, if that's something that they're interested in doing, I do think that that's a reasonable thing to consider only because many of those complications are not seen for many years afterwards. So, it's an individual call. But, you know, again, we take age and complexity to trying to find the right device for everybody.

Melanie Cole, MS: And how long do these pacemakers really last? What happens when the battery runs low?

George Waits, MD: Yeah. So, it's great that the batteries last a lot longer than the initial models. You know, the first pacemaker famously last for, I think, about six hours. But nowadays, we're talking 10 years is a good average battery life. And this is true for both the traditional, what I call, transvenous models with the wire as well as the leadless pacemakers, really long battery lives.

And in the case of the traditional pacemaker, when that battery starts to reach its end of its duration, we are monitoring that patient, you know, throughout the time that they have the implant. But certainly, as it approaches the end of the battery life, we are meeting with that patient more frequently and monitoring through remote monitoring systems that we have available, and that allows us to appropriately schedule a battery change. And in many cases, the only thing we have to change is what we call the can or the pulse generator, which is about a half an hour procedure, and patients go home the same day, and their battery is good for another 10 years after that. So, a very minimally complex scenario.

In the case of a leadless pacemaker, because they're so small, either we can remove the old device and put in a new one or, in some cases, you know, depending on expected longevity and those things, you know, we might even be able to just implant an additional device, and leave the other one where it is.

So, again, it's an individualized approach. But usually when it comes to restoring, you know, changing the battery, it's not nearly as complex or as complex as the initial implant.

Melanie Cole, MS: Or as it used to be. And I mean, really, the technology is amazing, and it's such an exciting time in your field, Dr. Waits. So looking ahead, what emerging advances in cardiac device technology are you most excited about? I mean, with the advent of AI and even televisits to help you monitor your patients, tell us a little bit about really what excites you beyond today's leadless pacemakers.

George Waits, MD: You're right to say there is a lot of great innovation that's happening. I think the two most recent advances that I'm most enthusiastic about is how, you know, everything that I've said earlier about conduction system pacing and, you know, that has developed over the last 10 to 15 years, but it's been focused on the way that we pace the ventricle.

And there's also a growing interest in applying that same rationale towards pacing the top chambers of the heart, the atria. So, you know, since earlier this year, I've adopted a new style of implanting, doing conduction system pacing in the atrium through direct pacing of an anatomic structure called Bachmann's bundle, which is, again, one of those conduction system components in the atria.

And, you know, there's a lot of hope, not proof yet, but expectation that we may be able to do a better job in pacing, perhaps preventing atrial fibrillation, perhaps managing heart failure better. Again, unproven claims. But good physiologic reason to suspect that we may be able to do a better job for our patients by pacing Bachmann's bundle.

The other advance is what I mentioned to you about leadless pacemaking's limitation not currently being able to pace conduction system fibers. There are efforts underway to change that where the leadless pacers can pace deeper into the heart muscle tissue and restore normal conduction.

And I really think, you know, once we figure out the practicality of doing that well, and if we can establish tje same reliability that we enjoy, you know, with the transvenous systems, I really do think that could change the field, and we could be putting in more leadless pacemakers, and people could be having less of a drawback, you know, less soreness in the shoulder afterwards, which is a common, you know, issue that people face in the existing models.

So, a lot of exciting changes there. I love, you know, the idea of being able to help patients by correcting their heart rhythm. And so, these are just some of the things that, you know, on the horizon.

Melanie Cole, MS: Thank you so much, Dr. Waits, for joining us today and really sharing your incredible expertise and explaining it in a way that we can understand, because it's really highly technical, but very exciting. And thank you again for joining us. And to find a physician, you can always visit novanthealth.org. And for more health and wellness information from our experts, visit healthyheadlines.org. I'm Melanie Cole. And that concludes this episode of Meaningful Medicine, a podcast from the specialists at Novant Health.