Transcription:
Advancements in Pacemakers

Bill Klaproth: So what is a pacemaker and what are the most common forms used and what about recent advancements? Let's find out what Dr. Micah Roberts, an electrophysiologist, which is a cardiologist specializing in heart rhythm disorders at Dignity Health. Dr. Roberts, thank you so much for your time. It's great to talk with you. So first off, what is a pacemaker?

Dr. Micah Roberts: Thanks, Bill, for having me on. Pacemakers are an electronic device that most of the time is implanted inside of patients and it's able to send a signal into the heart muscle and cause the heart to beat. Most of the time these devices include a battery source and a wire that goes into the heart. And through that wire, it's able to sense when the heart is beating and when the heart is not beating. And if the heart is not beating, it can send a small voltage down to the tissue and cause the heart to beat or contract. Without having electrical signals in the muscle of the heart there's no pumping, patients are dying. And so, a lot of times people start to develop, issues where their heart will be too slow, or there is not a communication from the top chambers to the bottom chambers, and so we put in pacemakers to help make sure that their heart continues to beat at a steady pace in sync. And so that's, what a pacemaker is.

Host: That is amazing. Let me ask you this. So the pacemaker always reads the heart. It's not always working, but when the heart is either too fast or too slow then it kicks in, is that how it works?

Dr. Roberts: Right. So, pacemakers have actually been around for about 60 years and the first pacemakers we're in 1958. And, and these actually had wires that were attached to a box outside the patient's body. And those wires went into the patient's heart and it just sends a signal into the heart to cause it to beat. And since then devices haven't gotten much smarter. And so now we've got devices that are able to sense when the heart is beating and when the heart is not beating, it will wait a set period of time and it will send a signal down. So, you know, for example, if we set a pacemaker at 60 beats per minute, if there isn't a beat every second, it will see that there hasn't been a beat or an electrical signal that's been sent to the pacemaker and it will wait that period of time and then it will send a signal down to the heart to cause it to beat.

Host: Again, totally amazing. So then who typically needs a pacemaker?

Dr. Roberts: So patients that have a heart that's beating too slow, or if there is a signal at the top of the heart that isn't reaching down to the bottom of the heart, then, we actually put in a pacemaker. Oftentimes, people who need a pacemaker might be people that are, constantly fatigued. You know, if their heart is beating in the 30s, for example, that can make them feel very tired or lightheaded. Sometimes there can be beating at the top two chambers that isn't connecting to the bottom two chambers. So you can actually have the top two chambers beating at one rate and the bottom chambers beating out a much slower rate. We call that complete heart block. Where there's less signal or no signal getting down to the bottom chambers is kind of like if you've got a light switch and a light bulb and you're turning on the light switch, but the light bulb isn't going on, there's something in the wiring that isn't there. And so we put in pacemakers to make up for the wiring that is inside a patient's heart that is not working correctly.

Host: Right got it. So you were talking earlier on how in the old days, the box sat outside the chess and the two wires went in. Can you just give us a brief evolution of the pacemakers and new technology that is upon us, including the leadless pacemaker? Can you talk about that?

Dr. Roberts: Yeah, so over the course of the last 60 years, we've seen a lot of changes and a lot of innovation built into these pacemakers. That's been led by, several companies here in the United States, and the big things that we've seen has been an evolution in battery technology, the leads that's basically the wires that go down to the heart. You know, the materials that are used, the insolation that's used. How the leads are attached to the heart, different timing cycles, and the software that's built into the technology, how we communicate with the pacemakers and, we can actually communicate with them wirelessly by radio frequency, or now even through Bluetooth. And then what sort of information can we get out of the pacemakers? How often is it peace in you? How much battery life is involved? And the, you know, the latest thing that's come very common as is MRI compatibility. So nowadays pacemakers are all being produced that are MRI compatible. And so these things have evolved over time that, you know, the latest things that have come out with pacemakers. Is, one thing is called a His bundle pacemaker where we're able to actually, activate the heart's natural wiring system by tapping into the wiring system if you will. That goes from the top chambers to the bottom chambers and we think that there's probably a better squeeze function of the heart when we were able to do that. And then a lead-less pacemaker where the traditional pacemaker will have a box that typically sets up in the shoulder underneath the skin. Lead-less pacemaker doesn't have that. So we actually put that device completely inside the heart and it looks like, sort of like a big pill that's attached to the heart with four tines that are inserted directly into the heart muscle.

Host: So let's talk more about the lead-less pacemaker. Is anyone a good candidate for a lead-less pacemaker?

Dr. Roberts: That's a great question. You know, that the lead-less pacemaker has two different generations. One type that can only send some pace, the bottom chambers of the heart. The other, more recent iteration of it can actually sense when the top chambers are contracting and it does that with a gyroscope that's inside of the device. And then based on the timing of the blood that's being pushed through it actually contract causes a signal to go to the ventricles and cause it to contract. And so it's able to time-based off of when the top chambers are beating. The problem is that we still don't have a lead-less pacemaker that can pace the top two chambers. So, if you need pacing at the top two chambers, then you're not going to be a candidate for lead-less peacemaker. And so those are people that have, something like sinus node dysfunction or sick sinus syndrome, where the beats originated in the top chambers aren't healthy. And so then we would need to actually put a lead into the top chambers to be able to pace that. But there are a lot of benefits to a lead-less pacemaker. You know, for example, there's no chest wounds, so there's no wound that needs to heal. There's no scar there's no bump in your chest. It's not tender. These chest wounds can become the problems where they can erode through the skin. They can cause hematomas. It can be a constant reminder when you look in the mirror that you've got this device in there. The leads that go from the device in your chest, they can fracture the insulation that's around them can breach. The vasculature can be occluded by those leads. They can actually, when it crosses the tricuspid valve into the right ventricle, it can actually cause the valve to not close and that can lead to a type of heart failure. And so it's about one and eight traditional pacemaker patients that will have some form of complication. And, recent studies have actually shown that the lead-less pacemaker has about a 63% reduction in major complications as compared to a traditional pacemaker. And, so I, really try to find patients that could benefit from it and, make sure that they were aware of this option. Because I think it is going to be sort of the future of pacemakers.

Host: Right. Well, the benefits certainly are easy to see. What about the procedure for the leadless pacemaker? What does that look like? And then why is that a benefit to you the surgeon and the patient?

Dr. Roberts: And so, the leadless pacemaker is implanted through a sheath that goes through the femoral vein. So right at the top of your leg, we put in a sheet, that's probably about the thickness of, you know, my pinky it's about the thickness of sort of like a nice writing pen. And that will go into the vein. You know, your vein can easily accommodate that and it's delivered all the way up to your heart. And then it's delivered across the valve and implanted directly into the right ventricle. It has these, we call them tines it's for nitinol wires essentially that when it's advanced to the tissue, it curves back on itself. So it pulls the pacemaker into the tissue and adheres very tightly. You can imagine if that dislodges, that thing, would float up into your lungs potentially. And so it's very important that it's adhered and attached and the whole thing because it's so small, it actually, get completely covered by your own tissue over time. And so, you know, blood will flow around it cleanly without, without causing any issues. And it was actually lower risk for infection. There is no wound, there's less risk of infection, there's actually less need for any sort of fluoroscopy. It's usually a quicker procedure. So, I've done these on patients that are in their late nineties and they tolerate it really well. They can get up and walk, you know, a couple hours later and so they're really doing well with these devices.

Host: That is so cool. So I think most of us listening have a general knowledge of pacemakers that you're able to monitor the pacemaker while the patient is at home through technology or the phone line, or I'm not sure exactly how it works with lead-less technology pacemakers. Are you able to do the same type of monitoring?

Dr. Roberts: Correct. So, you know, devices now it's really one of the standards of care is that we're able to monitor these pacemakers remotely. So most patients, when they get a device implanted, they actually go home with a little monitor that sits next to their bed, and at night, the pacemaker will communicate with this monitor. If it's having any issues, you know, the pacemakers not working properly, there's, issues with a patient's own heart, you know, if they're going into some sort of arrhythmia that, you know, the device is alerted to look for. It will actually send us here at the clinic a report. So within 24 hours of this happening, we usually know that there's something going on. And so we're able to remotely monitor these devices. So both leadless pacemakers and traditional pacemakers, we have remote monitoring capabilities and, it's really nice cause we can provide, you know, real-time support to the patients.

Host: Absolutely. And then what about the longevity of a lead-less pacemaker?

Dr. Roberts: So all pacemakers, the batteries will eventually wear out. These devices actually have, at least the company, they anticipate 12 years of battery life, you know, depending on how much energy the pacemaker needs to be able to pace your heart. And then also how often it needs to be pacing. So, the 12 years number that actually comes from people that will only need to be paced about 13 to 15% of the time. So if you're going to be pacemaker dependent, it's probably closer to six years or eight years, and so then they, they would need to have it replaced. And lead-less pacemaker world that means I'm just putting in another one. And, you know, we actually think that most hearts could tolerate having up to three of these devices in place.

Host: So you don't remove the old one because you said the heart muscle grows around it so you just insert a new one in.

Dr. Roberts: Yes exactly so if, I have a young patient, you know, let's say that you know, they're 40 years old and they need a pacemaker I would probably choose not to put in a lead-less pacemaker in that patient. And the reason is because, it's easy to go in and open up the wound and put in a new pacemaker device and that's something that can be done numerous times over the course of a patient's life, whereas a lead-less pacemaker, you know, you can only do it so many times before you sort of run out or real estate. And so, you know, we, we typically will target patients that have more medical comorbidities and are older that need pacemakers for the lead-less devices.

Host: Wow, this is really, really interesting. So last question, Dr. Robertson, thank you for your time. This technology is amazing. What do you see coming in the future as far as other advancements in pacemaker technology?

Dr. Roberts: So, you know, we talked about, then one of the limitations is that we can only pace the ventricle. So these lead-less devices, I think that there's going to be atrial lead-less pacemakers so we can potentially implant one device up in the atrium and another one down to the ventricle and potentially these two can communicate back and forth with each other to time appropriately. So I know that that technology is coming. There's also, you know, similar to your cell phone that can charge wireless so you can set it on top of that, you know, a charging port and it can charge wirelessly. There is technology out there where these devices can start to be, you know, charged wirelessly. So, you know, you can imagine yourself sleeping on a pillow at night that can send signals into the pacemaker and charge it overnight. There's actually starting to be STEM cell research being done so we can potentially inject STEM cells into people's hearts where those STEM cells can cause you know, a biologic pacing within the heart itself. That's not something that we would be able to necessarily control like we can with an electronic pacemaker. But if that's successful, then, you know, we can potentially do away with pacemakers all together in the future. So there's a lot of things that are being thought of and being worked on, with pacemakers and it's a great and exciting field.

Host: We'll be watching this space. Really interesting stuff as far as new technology for pacemakers. Dr. Roberts this has really been informative. Thank you so much for your time. We appreciate it.

Dr. Roberts: Okay. All right. Thanks a lot.

Host: That's Dr. Micah Roberts. For more information, please visit dignityhealth.org/bakersfield/heart. And if you found this podcast helpful, please share it on your social channels and be sure to check out the full podcast library for topics of interest to you. This is Hello Healthy, a Dignity Health Podcast. I'm Bill Klaproth. Thanks for listening.