CNA Conference - Dr. John Clark - CNA in the pediatric patient

So our next, uh, talk will be done by our co-host here, Doctor John Clark, who's the director of the arrhythmia Center at the Akron Children's Hospital in, uh, Akron, Ohio. Um, what a little bit about John. John is one of 11 children. I just figured I would say that, uh, and his talk will be, uh, cardio neuroablation in the pediatric patient. Being part of this today, I want to talk about cardio neuroablation in pediatrics, just as a reminder. CNA in pediatrics is not FDA approved yet. It's done as an off label procedure. Our experience in Akron spans the age ranges from 16 months to 38 years, and I find the ideal age is 20 to 40 years, but I just want to focus on our pediatric patients today. Um, we've done 14 patients at Akron with age range from 16 months to 21 years and a weight range from 8 to 139 kgs. I want to take you through some of the procedures, just starting with the simplest, straightforward procedures and advancing to the more complex. So, starting with vasovagal syncope. I like to begin when I can with a grid catheter. Um, it's 16 electrodes allow me to draw geometry very quickly, and at the same time we can capture atrial electrograms so that by the time we're done drawing geometry, we have both an activation map and a fractionation map. When we get done with right atrial geometry, I will advance the catheter across. The septum either by PFO or transeptal puncture and create a left atrial geometry. When we're done with that, we get something that looks like this, and we change the filterings and look at fractionated signals. And so this map will show us areas of white that are the areas of interest. We'll go back to those individual areas and decide which ones need ablated. Then we want to reproduce the patient's clinical situation, so either sinus node arrest or AV block. We do that utilizing extra cardiac vagal stimulation. With the insight system, it's very easy to advance a catheter up the SVC and into the jugular vein. Once we get it into the jugular vein, then we'll look by ultrasound. Here's the jugular vein here, the carotid artery here, and the vagus nerve lives right there. So, we are positioning the catheter tip on the vagus nerve and using ultrasound to confirm that that is where the catheter is located. Then we'll connect it up. We'll connect it up to a stimulator. I don't have access to Dr. Pashan's stimulator because it's not FDA approved in the US, so we use the digit timer. I like the digit timer because it offers us almost infinite variability in our outputs and lets us very closely mimic what Dr. Pashan is able to do in South America. We reproduce the patient's clinical situation, and then we find the areas that we want to attack. In this case, uh, GP site number 2 was targeted first, and there are sites here in GP site. Number 4, sites down here and GP site number three, but we didn't need to go after any of those because once we finished with GP site number two, there was no longer any sinus bradycardia or AV block associated with vagal nerve stimulation. Um, and this just reminds me to comment that extra cardiac vagal stimulation really is so important for these procedures because it tells you when you're done. Um, if you're still having bradycardias, then there's still more work to do. But once you reach the point where you no longer have bradycardia, then you can stop. And it doesn't matter if you've only addressed a single area in the heart. If it's enough, then you've not done too much. What about AV block, OK? Sometimes we get asystole and we really want to look for AV block. In that case, we'll pace the atrium, confirm that we're capturing and not conducting. So, we've reproduced the patient's AV block. And then when we re-stem after the procedure, hopefully we see no further sinus bradycardia and no further AV block. Moving on to the more complicated patients, let's size the patient down a little bit. An 8 year old with SVT, 23 kg and sinus node dysfunction. His small size prohibits the grid catheter use and by choice, I don't use the irrigated tip catheter on anybody under 18. Here is his baseline EKG. You can see he's in the sinus bradycardia with a junctional escape rhythm, and that's his rhythm all the time. He's either in SVT or he's in a junctional bradycardia. Here was his map. His SVT proved to be AVNRT, so we ablated that first. We then drew his right and left atrial geometries and found the areas that we wanted to ablate. In this case, we went after GP site number 1 1st and GP site 2 2nd, each time doing vagal stim in between until we reached the point that we were complete. Everything in this case was on the right side. We could have gone to the left side, but we didn't need to because he no longer had a vagal response with ECVS. This was his EKG at baseline prior to the procedure, and this was his EKG post procedure, and at 3 months post procedure, his sinus node remains awake and active. Going further still, let's get into the extreme of smalls, an 8 kg 16 month old toddler. Well, why in the world would you ever do CNA on an 8 kg baby? Well, because she had long QT type 3 and breath holding spells and syncope. Any time she bumped her head or bumped her elbow or her dad yelled at her, she would cry and pass out. She had an implantable loop monitor which documented asystolic pauses, her longest of which was 28 seconds associated with her syncope. She had no VT, no VF, no torsos. Um, but I can't leave a long QT type 3 patient with 28 2nd asystolic pauses. So we talked with the family about putting a pacemaker in. We also talked about CNA and elected to do CNA. The issues in her is her small size meant I can't use the grid catheter. I couldn't even use a standard RF catheter. I had to use a 5 French Mariner SCXS, the tightest curl, smallest RF ablation catheter made. Um, and even in that it was wall to wall within her left atrium, but the most important issue in her case was that I couldn't get a vagal response in attempting ECBS, and Of note, uh, this was at a time before we were using ultrasound to position the catheter. And I think if we could do this case over again today, we wouldn't have a problem with getting a vagal response, uh, because we do better know that the catheter tip was on the vagus nerve. Um, so we did it without ECVS. Uh, we got an increased sinus rate during the procedure, but when we gave atropine, she still had a positive atropine response, which was disappointing. Um, she continued to pass out afterward, went on to get a pacemaker, and for a little more than a year with her pacemaker now she's not had any further syncopal events. So we attempted to avoid the pacemaker but failed. This was her geometry again. This is a 5 French ablation catheter just emphasizing how small her heart was, how much little room we had to move around in. Moving on to the most complex patients, the complex congenital heart disease patients, uh, starting off with a 13 year old patient with dextrocardia, hypoplastic left heart syndrome, single ventricle status post fontan operation with a fenestration, who had sinus node dysfunction. Here is his anatomy. When we inject the SVC, you can see that the blood flows into the right and left pulmonary arteries. You can see his dextrocardia here. When we inject the IVC, the blood flows into the Fontan baffle and into the branch pulmonary arteries. So, completing the Fontan operation then eliminates your catheter's ability to get to the heart. When we inject on lateral, you can see a shunt right here, some contrast flowing from the fontan baffle into the atrial proper. We can see that also on echo. Here is his tricuspid valve. This is his right ventricle. He does not have a mitral valve. This is his right upper pulmonary vein. Here is his fontan baffle, and here is the fenestration with a shunt squirting across that fenestration. I could easily get a 5 French mapping catheter through that fenestration, and so we did. Here is his geometry as drawn by Insight. IVC fontan baffle, right and left pulmonary arteries, and SVC on the lateral view, I could put the catheter through the fenestration into the functional left atrium. We could draw a left atrial anatomy, and we did. There were some sites here, here, and back here of interest. However, transitioning from a 5 French mapping catheter to a 7 French ablation catheter. It was almost prohibitive. The size of the fenestration really snagged the catheter strongly and did not allow for movement of the catheter through that hole. We could get to a couple of places to deliver some lesions at the fractionated areas and actually did wake up his sinus node in the cath lab, um, but whether or not that's going to be enough for a long term benefit remains to be seen. This particular case definitely influenced our subsequent cases. Um, our next complex heart patient was a 5 year old. Again, complex single ventricle intermittent AV block status post the pacemaker. And she was scheduled for a Fon and she'd had her pacemaker for several years. Um, she paces 2% of the time, so 98% of the time she's on her own. She's a good candidate for CNA, um, but I'd really rather wait until she's bigger. However, when they do the Fontan operation, I have learned my access is going to be very difficult. So, after discussion, We decided to do the CNA prior to her Fontan operation. One of the struggles was that because her SVC was disconnected from her heart, I could not do extra cardiac vagal stimulation. However, we could map the areas very well, do the ablation, and at the end of the procedure, she had a negative atropine response. Um, in the follow-up, she's paced 0% over the subsequent 8 months with a couple of Holter monitors showing no pace beats. So, long term, uh, hopefully she does not continue to need her pacemaker. This is her anatomy. This is her IVC coming into her common atrium. This is her right upper pulmonary vein. Her SVC would be here, but it has been disconnected from the heart. Her lesions were delivered mostly in the area of what would be GP site number two with a few additional lesions over in GP site number 4. So summarizing, CNA in patients of pediatric age can be done safely and effectively. However, the ideal age, size, and indication has yet to be defined. Other questions can a good map be obtained without grid catheter? What are the appropriate targets in children? How durable will the effect be with non-irrigated catheters, and who is the best candidate to answer all these questions, it's going to require a database. To that end, Dr. Prashan will be opening a database in 2024. Anybody who is interested in joining that database, please reach out to us. What are my indications for CNA in pediatric patients in order of priority, my number one indication would be to avoid pacemaker implantation. In any child who has bradycardia that is res res. Due to vagal influence and a decision has been made to implant a pacemaker, um, I would say do the CNA first because if you can avoid pacemaker implantation, you save that child a lot of headache down the road. Along the same lines, I would use it to allow pacemaker removal. If a patient already has a pacemaker due to vasovagal syncope or functional AV block, then do the CNA to offer the possibility of not having to replace that device down the road. After that, straightforward vasovagal syncope, if it's documented cardio inhibitory, recurrent, and medically refractory. Then when the parents and the patient have reached their endpoint, then I would say, OK, it's time to consider CNA. I didn't have time to talk about it today, but we had one patient with refractory seizures, and during her seizures she was having high grade AV block with asystolic pauses of greater than 10 seconds. Neurology was very nervous about adding medications to her care, also concerned about using a vagal nerve stimulator, uh, both of which could worsen her bradycardia. So they asked me to put in a pacemaker, but instead we did a CNA. Um, eliminating her high grade AV block and allowing broader treatment with, uh, anti-epileptic medications, and she's controlled now without a pacemaker. Arrhythmias induced high vagal states like long QT or rugada, there may be some indications and some protection of CNA in certain patients. Um, one possibility is congenital central hypoventilation syndrome. Most of those patients are going to progress to need a pacemaker eventually, and I would question, can we delay or even prevent the pacemaker by doing a CNA in those patients? And then finally, pacemaker dependent patients. If I have a patient with complete heart block, um, with no underlying rhythm, can CNA give them some type of escape rhythm, because even doing that can be beneficial to them. And then lastly, the most important or most valuable piece of advice I can give you is that if you're going to do CNA in pediatric patients and you do it well, the parents will be extremely appreciative. So to maximize the benefit to everyone involved, always be sure to ask the parents for chocolate chip cookies because if you ask, they will deliver. I want to thank everybody for being here. Any questions or suggestions, don't hesitate to reach out to us at heartbeat@ Akronchildren's.org. And if you're interested in joining the database, please reach out to us at info@faintqc.org. Thank you. OK. So thank you, Doctor Clark. Uh, I obviously don't have any questions because I'm always along for the ride. So I know we had a little bit of a discussion during the presentation. Uh, Doctor Patone, did you have any questions for Doctor Clark on this? Yes, uh, uh, uh, I think, uh, I was, uh, curious about that case of, uh, with commitment of the breeding. Uh, did you, uh, see any change of the respiratory activity of the, I, we haven't done that yet. That one I was raising a question. I've got, I've got two patients with congenital central hypoventilation syndrome that I'm, I'm sort of. Kicking the idea around, um, and neither of them have reached a, an indication yet for a pacemaker, but I, I lean toward when that time comes we do the CNA, but because it's, it's genetic and it's progressive, I'm just, I'm wondering if it's gonna work, um, but I, I would still lean toward that first because one of the vagus effect is to stop the bleeding. And by activating the Pneumotax sender. So it, it would be very interesting to have the possibility to change the vagus because we have been observing, but because another effect of the vagus is to cause um sleep apnea because it uh it causes a refraction of the tongue. In order to, uh, obviously to obstruct the respiratory, uh, airways in order to avoid the drowning. So it is, uh, an effect of the vagus. So it's very common that after the card node ablation, there is a Improvement of the sleep apnea of the patients. It's very, very common. And I, I, uh, I am extremely interested in this case that you observed the, uh, the problem of the respiratory problem. It is very interesting. So I'm gonna, uh, take one of the questions here. We have a couple of questions, uh, we'll answer, uh, the other ones through the chat, but, uh, Amar, uh, Nawar, uh, she's a young girl, 15 years old. Uh, she had syncope almost twice weekly, uh, after, uh, she's free from syn syncope now for 7 months, but she's having inappropriate sinus tachycardia, even resistant, uh, to, uh, uh, yeah. And, uh, any beta blockers. So any comments on that, Doctor Clark? Yeah, I've had a couple of patients like that who have been referred with both vasovagal syncope and POTS. And uh I've talked with them about, you know, if I do the CNA for the vasovagal syncope, we may make your pots worse, we may make your Sinus tachycardia worse, and one lady we did in fact do that. She was sitting with a resting heart rate under anesthesia during the procedure, um, for the CNA with a heart rate of 110. And when I finished the CNA component of it, her heart rate was 125, and I said, I, I can't leave her like that. So during the same procedure, we came back to the right side. We mapped the sinus node. And we did a sinus nodal modification and and got her heart rate down to 85. And uh she had not seen a heart rate of 85 for a couple of years. Um, so that, that worked out well, but when you do that, I'm, I don't know, that's a clinical judgment, you know, when, how many medications have you failed and how symptomatic are they before you decide to, to go in and try and modify the sinus node under those circumstances. Thank you. Uh, next, Doctor Clark, we have Gabe and Drew. You want to give an introduction on that? Yeah, Gabe and Gabe and Drew are a couple of young men, uh, identical twins that I've known since they were 6, both of them with vasovagal syncope, both of them with prolonged pauses of 10 to 30 seconds and syncope and seizures, and both of them got a pacemaker when they were 6, and I followed them with pacemakers. Uh, since then, um, but it is purely vasovagal, um, and so we've talked recently about, you know what, this might be an opportunity for you to get rid of your pacemakers, and so both of them back to back underwent CNA procedures with anticipation of eliminating their need for a pacemaker. And we've got a little six-minute video about that, and then we're gonna continue on with our next speaker right after that video. When I was 6 years old, I passed out on the playground at recess. I had a seizure and I woke up inside. And my family and parents didn't really know what happened to me. Having seizures were rare, so we wanted to figure out what exactly happens. So I received a Holter monitor to wear for 24 hours in hopes of me having one of these episodes while wearing the monitor. And luckily I had a seizure while wearing this monitor. So after tests and a few days in the hospital, I had to receive a. Maaker because I was diagnosed with sinus node dysfunction. So the very next week, um, I had to come back up to Akron Children's Hospital, and they did some tests and I had to wear a heart monitor for 24 hours. And the moment they put the heart monitor on me, I had a seizure and my heart stopped for 20 seconds and that's when Doctor Clark knew that I had the same problem as him where my heart would stop beating. And I was shortly diagnosed with sinus node dysfunction and had to get a pacemaker the following week. Having pacemakers in kids is rare in general. It's it's it's hardly heard of, but having it in twins with the same exact problem. I could probably count. There's probably not even enough cases to fill my hand. So when we were referred to Akron Children's Hospital, we were instantly connected with Doctor Clark and ourselves and my parents included, we felt a natural bond to Doctor Clark, but my parents, they had so many questions about the procedures, what's going to be done, and so they would ask Doctor Clark. If these were your kids, what would you do? And Doctor Clark gave him the most honest, honest answer, and that was really encouraging because through that he became to know us more and we began to develop a bond to him, just seeing him for checkups and through surgeries, and he's become family to us. So when Doctor Clark was down in Brazil learning about this procedure, he was thinking about us the whole time, which is a special thing to feel because we are top candidates. See, we were in our twenties and we use our pacemakers less than 0.01%, which is basically. So we were perfect candidates for this procedure as we were moving out of our youth and relying heavily on our pacemakers into this period of should we get them out? Should we turn them off, we don't know. So this procedure was perfectly implemented for us. So the first month after was. A pretty interesting recovery. The first week our heart raced about 10 beats higher per minute for the next 34 weeks, and our heart would just like flop. It would skip a beat. It would start paling and pounding harder, so it's very interesting, but as time went by, it sort of went its normal route. Yeah, it was about the same, um, right after the surgery we had chest pains. Obviously we felt our heartbeats and flop and. There was just some soreness in our chest, but after a few weeks our heart went back to equilibrium. Everything was seeming to be normal and I guess our wound healed up, so he tried to slow down our heart and even stop it so he can read which which nerves or which sections made my heart stop and slow down. So he mapped out our heart first and found which nerves led to that result and then through the next 4 hours he sort of just kind of like sutured off those nerves and at the end he tried to do the same exact thing he did before and it was that my heart didn't slow down or stop beating, so that's how he ultimately knew the procedure was a success. So I can I guess live my life more courageously and confident knowing that. I won't have situations where I'm going to pass out compared to when I would as a kid. Just with our past, I think it's encouragement to others, no matter what surgery or medical operation they're going to get, just knowing that we had extreme health problems when we were so young, 6 years old. And now, um, so it's very encouraging to others to hear our story and help them, um, give them a sense of peace whenever they're about to go through a heavy medical situation. Identical twins having the same problem, um, it's just very encouraging because we went through similar things in our life. We would be encouragements to each other if we had procedures, uh, coming up. Because we went through the same exact thing, so I had my heart ablation done a week before him, and leading up to it, he was pretty nervous, but I just gave him that peace of mind going into it. He saw that I was pretty healthy coming out of it, so he felt pretty confident going into it. I'm just thankful for all the medical staff here at Akron Children's Hospital. They've been so caring and kind. For the last 15 years, and I'm just very thankful we chose, uh, Akron Children's as a hospital. Yeah, um, the staff has been incredible. I know what we faced as kids was really challenging, but, um, ourselves and our family included just relied on community and other people just to, just depended on other people for meals and for care, and we really found community in our church and we're just very thankful for all the prayers and support through the years.