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The Beat Webinar Series - Episode 8 - LIVE from Ne ...
The Beat Episode 8
The Beat Episode 8
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Good morning everybody. Welcome to our BEAT. This is sponsored by the Heart Rhythm Society and PACES, the Pediatric and Adult Congenital Society of Electrophysiology. So we're here to discuss some cases of genetic arrhythmias. We have an excellent panel today of some wonderful experts in the field and let's get started here. So this is in partnership again with the PACES organization and Heart Rhythm Society. The disclosures are listed here for review and I'm going to introduce our first panelist which is Dr. Susan Etheridge from the University of Utah and she's going to take our first case. Dr. Etheridge. Thank you. Thank you all. Can you hear me? Perfect. So this is a recent case actually although we first met him in 2010. At that time he was six years old. He had collapsed in the middle of the night. The family heard a thump. They went into his bedroom. They found him unresponsive. EMS was called. A successful shock was given for VF and epi was given. He then was transported but had recurrent VT in the ED and in the CICU. This was one of his events while in the CICU and you can see fairly classic if you look on the bottom which is V5. Fairly classic bidirectional ventricular tachycardia and bidirectional ventricular ectopy. Once we got him under control his sinus rhythm electrocardiogram is pretty normal. His corrected QT interval is normal and as you can see his T waves look pretty normal for a kid his age. During that hospitalization he had frequent PVCs. Every time we'd stimulate him he had ventricular tachycardia and this was in fact responsive to us sedating him. He had a normal echo and MRI and esmolol was started and he was eventually converted to oral nadolol. His past medical history is interesting. He had mild skeletal muscle weakness and a few months before his original presentation he had had a seizure that was associated with a minor injury while playing. He was sent to neurology he had a normal EEG and the neurologist did not think this was a seizure disorder and he was not started on medications. So we thought ah this is the clinical picture consistent with CPVT or catecholaminergic polymorphic ventricular tachycardia. We sent a genetic panel for that and it was negative in 2010. Still we continued the nadolol and he really did quite well. He had some mild developmental delay from his original arrest but was arrhythmia free until this past February and he was readmitted during a VT storm. So he had had an ICD storm at night in bed not while sleeping doing what teenage boys do at night in bed. He had had numerous arrhythmias, 10 shocks despite what he says was compliance with his nadolol at 40 milligrams BID. So you can see here he gets a shock for VT and he goes into AFib. Here's some atrial fibrillation and then a slightly more regular atrial tachycardia associated with a rapid ventricular response. Here he is in a fairly regular narrow QRS tachycardia that then degenerates into VF. Here he is getting a shock for VT or VF that puts him into AFib and it was just a nightmare. So while he was admitted during that hospitalization he had rapid whole genome sequencing that was performed and while he was still in the hospital this returned positive for two loss of function mutations in triadin. So you can see them there. I'm not going to repeat them. One of them was maternal and one was non-maternal. Now his dad is alive but not available for trio testing. So at that hospitalization we initiated flecainide, continued his nadolol and scheduled him for a left cardiac sympathetic denervation and he has done well since this. So I think as we have learned not all arrhythmia in CBVT is bidirectional ventricular tachycardia. Here's an example from the literature of somebody going straight into polymorphic VT. Even in Leonhardt's original description bursts of atrial tachycardia were seen and atrial arrhythmias were fairly common. Here's a really cool example from the literature of the termination of bidirectional ventricular tachycardia with the onset of an atrial or supraventricular arrhythmia that may actually have been the reason that the VT terminated interestingly. So this is the calcium release complex. It's responsible or it's part of what is normal cardiac contraction. So it's composed of the reanidine receptor, calsequestrin 2 and other associated proteins like triadin. I'm clicking a lot so click a lot. So the genetic causes of dysregulation in intracellular calcium involve mutations or what we now call variants in genes that encode the calcium release proteins. Stress-induced adrenergic stimulation can lead to enhanced sarcoplasmic reticulum calcium reuptake and overload and the arrhythmias that we associate with CBVT. Keep clicking. You can see calcium is released in diastole. The heart doesn't like it. It exchanges it for sodium. The sodium, keep clicking, depolarizes the cell, causes these delayed after depolarizations and then when you add stress to that, and stress isn't only exercise as we saw on our boy, you can get the bidirectional ventricular tachycardia. Sodium is important especially when considering therapy with laconine. So this slide will show you what we know now about the gene variants responsible for CPVT. The vast majority are still in RYR2, 5% in CasQ2, but we're starting to uncover other genes like triadin that cause CPVT and to date still about a third of CPVT is genetically elusive. So triadin, I didn't know anything about triadin before this case. It's thought to act mainly as a scaffolding protein to help anchor calciquestrin to the ryanidine channel. When it's knocked out in mice, protein levels of ryanidine and calciquestrin and junctin are all reduced despite normal RNA expression and consistent with its, this is all consistent with its role as an anchoring protein. It localizes to the sarcoplasmic reticulum both in cardiac and in skeletal muscle, hence the skeletal weakness that is seen in this population. To date the triadin CPVT patients have a pretty severe phenotype like my patient. They have arrests at under six years of age and to date the CPVT associated with triadin is either due to homozygous or compound heterozygous mutations and there are some inventive therapies that are coming down the pike. Gene delivery of calciquestrin or triadin and then treatment with this drug called kyphosazine that I can't pronounce, so I apologize if you're working with that drug. There's also this really interesting condition called triadin knockout syndrome where patients have multiple events like we've talked about, mild to moderate muscle weakness, ECG with T wave inversions and lead V1 through 4 which our patient didn't have and QT prolongation that can be present sometimes and not all the time. So an overlap between CPVT and long QT syndrome. Thank you. Excellent Susan, thank you so much. Our next speaker is Dr. Prince Kanakaril. Dr. Kanakaril comes to us from Vanderbilt University and he's going to be talking to us about our next case. Yes, thank you Pete. So I'm talking about a newborn with bradycardia. The bradycardia was actually first noted in utero. This child had, or the mom I should say, had fetal echocardiograms starting at about 20 weeks showing a sinus or an atrial rhythm with a heart rate between 92 and 113 beats per minute. The heart itself was structurally normal and mom had normal labs and a normal ECG. And so when I say fetal bradycardia you may mean, you may ask what does that mean? So traditionally a heart rate of less than 110 beats per minute was the definition of fetal bradycardia. But as I'm showing on this slide work from Bettina Cuneo as well as Susan Etheridge has really defined the normal heart rate range throughout gestation. And you can see that it drops throughout gestation but the third percentile is actually well above 110 beats per minute. And so on the top right hand side are fetuses who were postnatally diagnosed with long QT syndrome but had no abnormal arrhythmias. So these are essentially asymptomatic long QT syndrome patients. You can see many of them have heart rates less than the third percentile for age but higher than the traditional 110 beat per minute threshold. So now our fetal cardiologists are getting much more suspicious about long QT syndrome in this population. And so on the next slide is the first postnatal ECG and I apologize there's a little bit of artifact at the beginning which we often see in newborns. But you can see a sinus rhythm with 2 to 1 AV conduction and very severe QT prolongation with a QT of around 700 800 milliseconds. And so when we see newborns with 2 to 1 AV block due to long QT syndrome we think of course about long QT syndrome type 3. Okay there are many studies showing this. I've put two on the slide here. One from Japan and one multi-center study led by Jeremy Moore one of our former fellows. And if you look at the newborns who present with 2 to 1 AV block you'll find most of them have long QT type 3 or mutations in SCN5A. So of course that's what we were thinking this child had. Now she was hemodynamically stable. We started her on IV lidocaine and esmolol and made plans to put in a pacemaker the following day. But on the next slide you can see her ECG on day of life 2. This is on esmolol and lidocaine. She now has recovered 1 to 1 AV conduction. She still has severe QT prolongation and this is a really nice example of macroscopic T-wave alternans where you've got a complete flipping of the T-wave from beat to beat. Now that's never a good sign but for this child she's actually doing a little bit better right because rather than 2 to 1 AV conduction she now has 1 to 1 conduction. So we put the pacemaker on hold. We transitioned her to propranolol and flecainide. And this is her ECG on day of life 10. You can see she's again in sinus rhythm with 1 to 1 conduction. Her QT interval is still severely prolonged. It's 5 to 600 milliseconds or so. But she's had no more AV block. She's doing well. She's feeding. There's really no reason for us to keep us in the hospital so we send her out. I plan to see her back in clinic. And so on the next slide you see her ECG when she comes to clinic at 3 weeks of age. She's back in 2 to 1 AV block again with her QT interval around 700 milliseconds. And she's got no symptoms. Her parents tell me she's doing just fine. There's nothing wrong with this child right. So my clinic is on a Friday. I send a flecainide level. It later comes back at 1.14 so she's clearly taking her medicines. And I had to sort of make the hard decision on what to do with this child. So I'm going to actually ask Pete what would you do with this child who's in clinic doing well but in 2 to 1 AV block due to severe QT prolongation? I mean I think for a patient like this just knowing the literature and personal experience shows that these patients and with the TBF alternans tend to be a bit tricky and are prone to badness as you had mentioned. I think very close monitoring obviously if this is a patient you're going to be following in the outpatient setting. Whether that's real time telemetry is probably the best thing to do just to assess for occult arrhythmia. You may not know when a baby that's this young if they're having non-sustained torsades. What you would do about that? It's a bit challenging in somebody this young but you at least want to know that data. Yeah so those are the questions I wrestled with and I decided not to admit her but to do monitoring and so we did that and of course every day she sent transmissions showing 2 to 1 AV block. So when Monday rolled around and she was still in 2 to 1 AV block I brought her into the hospital, increased her propranolol to 4 mg per kilo per day and I switched her from flecainide to myxilatine and again penciled her in for a pacemaker because she was still in 2 to 1 AV block when we admitted her. And so you might ask why the switch from flecainide to myxilatine? So I didn't actually have that flecainide level back yet but I decided it failed her and again we can look at data that again Susan Etheridge has helped contribute. You can get fairly significant QT shortening with myxilatine in cases of long QT3 which again this is what we were suspecting at the time. And that plan actually worked really well for her. Okay so she regained 1 to 1 AV conduction. She still had pretty severe QT prolongation with a QTC of around 600 milliseconds or so but she's doing well on propranolol and myxilatine so again we cancel the pacemaker and we send her home on that regimen. And so she is still monitored. She has daily 1 to 1 AV conduction on her monitor. She's got no symptoms so she's doing okay. And then finally the genetic test comes back. We didn't do rapid whole genome sequencing. We did standard clinical testing and lo and behold she has a variant of uncertain significance in calmodulin 2. She has the D130N variant which had not been described before so it's a novel mutation. However, similar mutations that exact same amino acid location had been previously associated with long QT syndrome so we were very suspicious. We then tested the parents, determined this was a de novo mutation and that was enough information for the company to upgrade it to a pathogenic mutation. And so calmodulin is just really a fascinating story and I've put a little bit of that story on the following slide. So I've got Leah Crotty's initial paper that associated calmodulin mutations with severe forms of long QT syndrome. In that original paper she actually had the D130G mutation which is the exact same amino acid as our patient. And the basic science behind how these mutations cause long QT syndrome has been worked out. So on the slide here I've got some tracings of action potentials from, these are actually guinea pig action potentials, but in the setting of wild type calmodulin you see very normal action potential duration. When they're exposed to calmodulin with either one of the two mutations they first identified, you see severe action potential prolongation and the intracellular correlates of 2 to 1 AV block and T-wave alternans. Now why do these mutations result in APD prolongation? Well it turns out that normal calmodulin is required for proper inactivation of the L-type calcium channel. So when you take these mutations in calmodulin they actually disrupt the calcium binding site on the C-terminus and you lose that calcium dependent inactivation of the L-type calcium channel. And so that's what we suspect is going on with our patient. And so Leah Crotty has published the International Calmodulin Lymopathy Registry. The first paper came out in 2019. An update to this registry has just been accepted in European Heart Journal so be on the lookout for that. But calmodulin mutations can cause severe long QT syndrome as well as CPVT and idiopathic VF, but long QT syndrome is actually the most common phenotype with calmodulin mutations. And so this child's current status, she's now 27 months old. She's had no more AV blocks since those initial hospitalizations. Her QTC is still around 600 milliseconds. It's really stayed severely prolonged. Recently the family traveled to Mexico and then she came back, developed bloody diarrhea. So she was actually inpatient for about a week with diarrhea and she had no arrhythmias despite some periods of pretty severe hypokalemia. So I was encouraged by that. And now she's developed, or I should say we've recognized she has LV non-compaction on her echocardiogram with mildly depressed LV function. Her EF is about 50%. It's stayed in that range for about a year or so. And so I do have one image of that. And that also is part of the phenotype in calmodulin mutations. So this is a patient that I worry about a lot. She has persistently severe QT prolongation. She now has LV non-compaction, which can also be associated with a sudden death. So she's somebody who is a candidate for a primary prevention ICD really at any point, I suppose, but I'm trying to sort of keep her alive long enough until she gets big enough for us to do one that's a little less complicated than when she's an infant. Very nice. Thanks so much. All right. We have our next presentation is from Dr. Sabrina Tsao. Dr. Sabrina Tsao joins us from the University of Hong Kong overseas. That was at Lurie Children's Hospital prior to that. Sabrina. Thank you. So I say that I'm going to talk about Brigado syndrome, but I think it'll be an interesting case to share. So this is a four-year-old girl. She's previously completely well, no past medical history, and she just had an out of hospital cardiac arrest with documented VF by the EMS. She was successfully defibrillated, and she was brought into a private hospital. So this was the initial telemetry, and what they see is sinus rhythm with very chaotic atrial rhythm in between, as well as non-sustained VT. And if you look at the next click, is that she has a short coupling PVC inducing non-sustained torsade de point. So at that point, the private hospital decided to transfer her to us. So we did the usual. So the echo is completely normal, and some of her PVCs look a little bit like maybe Purkinje PVCs with idiopathic VF. But because of the short coupling PVC that triggered the VF, at the time, we asked an OVC expert and they said, this may be Brugado syndrome. And we're like, okay, the family history is completely negative. So we also did a cardiac MRI. There was no evidence of fatty infiltration of the myocardium or any wall motion abnormalities. And we did send a genetic test, which eventually came back as a VUS in SCN5A. The parent's ECGs were completely normal. So at this point, we were kind of wondering what to do with her. So because we have paper ECGs, I apologize for the poor quality, but this is what she looked like. She has sinus beats with a lot of PACs and runs of polymorphic PVCs, triplet. And she also can do this, which is sinus rhythm with runs of non-sustained atrial tachycardia. And she is completely hemodynamically stable during this. So what would you do, actually, Pete, at this point? How, she's stable, she just has these runs and she's okay otherwise, clinically? Right. So Prince taught us yesterday that in these situations, at least when you're dealing with a channelopathy, we don't know what channelopathy this is, but assuming that it is one, in the AT is kind of the background noise a bit. And as long as you're stable, perhaps being overly aggressive and treating the AT may not be the right thing to do unless you have another diagnosis that guides your treatment. Okay, great. So we actually offered drug challenge to the parents and they refused. They said, no, she just had a VFRS, we don't want that, even if it's low risk. So because we thought maybe this is a RVOT PVCs, we treated her with verapamil. There's minor reduction in the PVC, but then because of the ATAC, we also added sotalol. But that had to be taken off because despite a low dose, she was very bradycardic, 40 to 50. And so we decided to start her on flaconide and that miraculously actually controlled her arrhythmia at the time. However, we then started noticing this J-point elevation and T-wave inversion in V1, which she does not have at baseline. And so we took off the flaconide and we re-added the sotalol and started her on quinidine. Because we still don't really know what she has, for primary prevention, again, we gave her a SICD. Now this is in a very young child. And again, it's the parents absolutely refusing avocadial or transvenous devices. So she got a SICD. So she was discharged on verapamil and quinidine. So fast forward a few months, she had a febrile illness. She had sinus tachycardia with SC elevation, QRS widening, with T-wave oversensing. So this was on quinidine and verapamil. And she had an inappropriate shock. And so we want to rethink what she has so far. She had an abortive VFRS that was associated with febrile illness. We think she has some kind of sodium channelopathy. If you look at the Shanghai score, it's about 3.5 for her atrial arrhythmia and because of her VF arrest. She definitely had VF associated VGVF before. She has a Brugada type 1 ECG on oral flaconide. She has multifocal atrial and ventricular arrhythmias. She's had appropriate and inappropriate SICD shock. And so when we sent the gene test in 2017, it was a VUS and SCN5A. So last year we sent a whole genome sequencing and it was completely negative. And she has already proved to us that the quinidine failed to control her atrial and ventricular arrhythmia. And so we actually did restart flaconide and we stopped the verapamil eight months later. On flaconide, on repeat holters, she varies between 20 something to 40% atrial atopy with isolated PACs and runs of non-stained atrial tachycardia and actually very rare PVCs. She then moved to Singapore and she has not been able to come back to see us because of COVID. And what happened was she had a febrile illness during a COVID infection and she received another inappropriate shock. Now, eventually when Hong Kong opened back up, she managed to come back. And this is what she's doing on flaconide and actually Netolol. So you can see she has some sinus beat, but a lot of non-stained ATAC with variable AV conduction, but the P wave is definitely more uniform, but she's very bradycardic. And the parent says she's getting tired when she goes to play. And so in the end, what we decided to do is that the combination therapy is really not working. So let's take her to the EP lab and see if we can at least get rid of the atrial tach and maybe attack the PVCs. So when we brought her there, she definitely has a focal atrial tachycardia. And initially she has a lot of frequent RVOT PVCs and non-stained VT at baseline. But because we had to do transepto and all that after GA, we really couldn't get these PVCs to come back out. And we did a VT study that was negative. And posablation, with the mapping, we gave her a right bundle branch block pattern. She has dual AV nodal physiology, but no inducible AVNRT. And she has VA dissociation at baseline. And so we decided to do endocardium pace mapping to see if we can match the PVCs. And unfortunately, none of the area resembled the clinical PVCs. So this is a SPARCO map. On the left is the LAO view, and on the right is a posterior view. And you can see this focal atrial tachycardia around the three o'clock in the mitral valve annulus. And this is the, the next slide shows our successful lesion. You can see that she was in atrial tachycardia, slightly variable cycle length, variable AV block. And then she went into sinus rhythm. So this was a really nice ablation for that. About one month posablation, she has been off all antiarrhythmic. Her Holter shows that she's not that bradycardic, but does have a wandering atrial pacemaker and no PVCs. Now, she's now 10 months posablation. She's back in Singapore. At least right now, she hasn't had any SICD shocks. So as we all know, Brugada, the prevalence is three to five in 10,000. And the genetics is very nebulous, right? Only 30 to 35% are genotype positive. And most of them are from SCN5A mutation. And you can see in the diagram on the right, a lot of gene can be involved. There are risk factors for cardiac events. If you were diagnosed after syncope, the risk of arrhythmias is about 1.5% per year, which is four times higher than asymptomatic patient. With prior cardiac arrest, the cardiac event rate is 7.7% per year. As we all know, ECG is variable, but if you have a spontaneous Brugada ECG, the risk of sudden cardiac death is 2.3% per year. Male is a risk factor, and then the fever. So this is an interesting survey. It's a multi-center international survey on arrhythmic event in Brugada syndrome patient from 23 centers. And they included patients, including 57 young patients. 25 were younger than 12 years of age. And what you can see in the younger cohort is that 40% are female. This is very different to the older cohort. Interestingly, only 3.8%, one person, is Asian. And they have presence of fever during an arrhythmic event in about half of them. And 33% of them do not have SCN5A mutation. And some of them will have a sinus node dysfunction and atrial arrhythmias. And so what they come up with is with a risk factor for recurrent atrial arrhythmic event. An atrial arrhythmia gives you a hazard ratio of three. And in older age group is actually the SCN5A mutation. And if you look at, if you have any risk factor at all, then on the left is the younger age group. You really have a much higher risk of arrhythmia event recurrence. And so if you have documented sinus node dysfunction in the younger age group, this is a risk factor. Now for our patient, she did not have any family history of sudden death. And like the cohort, 31% of them without family history of sudden cardiac death presented with syncope or aborted sudden cardiac death. And only 21% has mutation in SCN5A mutation. And so for, if you have, for these cohort, interestingly no one dies suddenly, but some of them will have syncope. Only one out of them have documented life-threatening arrhythmia, with 8% with appropriate ICD intervention. I think for pediatric people, the scary part is that 33% has inappropriate ICD shock, most of them due to either AF or sinus tachycardia and device-related complication. And so I think that we don't have etchmaline in Hong Kong, but in this cohort, 24% of children undergoing etchmaline tests has a positive result. And children under 12 has a much higher risk of etchmaline-induced ventricular arrhythmia. And that's 10% versus 1.3%. And 25% of those under 12 will present with symptoms. And some of them were female. And a lot of them have atrial arrhythmia and sinus node dysfunction. So for my patient, she has fever-associated VTVF, atrial arrhythmia that we have treated, the ventricular arrhythmia that we haven't really done anything about, the flaconide partially controlled her, but gave her brugada ECG. What are her risks of recurrence? If you look at that paper, her hazard ratio is 6.9. So what we told the parents is that you have to treat the fever proactively and aggressively. And we would do periodic Holter and exercise stress tests. But she really doesn't have a real brugada diagnosis right now, she has a genotype negative brugada syndrome. And that's all I want to say. Thank you. Great job. Those are some nasty cases. Any comments from the audience? Any questions from the audience? While we're waiting, I actually have a question. So you took this patient to the lab to ablate her atrial tachycardia, which was very useful. Did you consider epicardial mapping of the RV outflow tract looking for high-frequency signals that you could ablate to potentially prophylaxe against ventricular arrhythmias? So yes, but not at that procedure. I think we were pretty clear of our goal. If she still has the PVC, we're definitely going to map. And we actually, apart from trying to do pace mapping, we did voltage mapping, and there was nothing endocardial. And so what my partner and I actually discussed this is that if she does come back with a lot of ventricular arrhythmia, the next thing is probably doing epicardial mapping. Yeah. Thank you, Serena. Thank you, everybody. I am wondering now, with these very phenotype-positive young children where we don't have a mutation, those are deceptions. We know that in the children that express the phenotype, almost 70% have a mutation, and many of them, when they're so young, have a compound mutation. So my question is, do we have to look specifically at these genetic positive, negative population to look at all the microtubular function and expression of the potentially normal channel in the membrane? I think that this is their minority, but we are now considering all the, not just the genetic part of the component of the DNA, but all the structure that makes that channel reach the membrane. So this is what we are trying to investigate. They're a minority, but this is part of the data we are collecting with the registry. And I think that's one of the reason we are so excited to join the registry, and I think that this is the type of patient that how are you going to counsel them as they get older? And what about the SICD? And I think all those are our questions, and we don't have the ability to do functional study, but I think this will be very helpful, yeah. I had a question for you, Prince, the calmodulin patient that you presented, in particular, the two-to-one phenotype in infancy, I think we've all seen, and that's the harboring of badness that we all worry about. One comment and a couple of the thoughts. The first is that in our CHOP experience, we wrote up, I don't know, 15 or so of these patients, and very few of them actually had long QT3 gene variants, and the majority had one or two, oddly enough. We sort of supposed that it would be three as well going into it, and this was, we published this paper when many didn't really have genetic testing at the time of their clinical presentation. It was something that we found out afterwards. The other thing about your patient, and I share a calmodulin patient as well, who had a very similar presentation, though she presented much later, would have two-to-one block, pseudo-block with exercise, actually, but was totally asymptomatic with a QTC nearing 600. Horrible phenotype on paper. You showed T-wave alternans in your patients. The calmodulin patients, even though the QTC seems to be nasty, don't seem to have the ventricular arrhythmias substrates that the long QT1 and 2s in infancy seem to. Do you think that there's a real difference there? Yeah, no, that's a great question, and so calmodulin patients with long QTC in general are fairly severely affected, and that's been documented by Leo Crotty's registry, but yes, the average age of events is four or not. There are some that have neonatal and infantile arrhythmias, but not all of them. I think a fascinating question in long QTC in general is why do some patients have such severe QT prolongation, but not a lot of ventricular arrhythmias, and there are others with more modest degrees of QT prolongation that have a lot more troublesome ventricular arrhythmias. I think that's a fascinating question in general, and it's probably not necessarily mutation-dependent. It may be polygenic risk that contributes to that, and it may be something completely different. I think that's the only macro two-wave alternate inside I've ever seen where the next side was not torsades, because I think everybody was anticipating that to be their next slide. Any other questions from our audience members? Hi, this is for Dr. Etheridge. It's interesting, the case you presented, I actually have a 29-year-old woman in the hospital who just got her ICD yesterday, presented with what seemed to be idiopathic VF, and initially her QT interval was normal, and over the course of the next few days, we saw some bidirectional VT. We saw a lot of lability in not only her T-wave morphologies, but also her T-wave intervals. Some Wellens-type looking T-waves, and from day to day, things would change very rapidly. Has this been described as well in the triad and mutations, this kind of rapid cycling of their repolarization, and would you recommend flecainide up front? Excellent question. I have read some cases about that. It's more about the intermittent QT normal, QT not normal. Actually, we did start the flecainide before we got the genetic test back, because it was such a classic CPVT variant, or phenotype. So in your patient, I don't know, Prince, you're the flec guy, but I would probably consider starting flecainide in the hospital for that patient, and you may see the arrhythmias and the T-wave changes get better. We did, our child stopped having the atrial arrhythmias, interestingly, stopped having the ventricular arrhythmias, and really calmed down. We still send him for a sympathetic denervation, although the data there are not super robust. She also had some atrial arrhythmia, and we haven't genotyped her yet, but certainly sounds like this might be her. And it's part of the, it's actually now part of the commercial genetic testing. It wasn't when I did it in 2010 for this kid. Does she have any children? No. Okay. Obviously, that's who we care about. Right, yeah, send them her way, right. The other curious thing about your patient is the first presentation, a 29-year-old. We obviously see him a lot younger. Yeah, no history of any arrhythmia-type symptoms that we could elicit, and it was interesting because she presented, she was with her fiance in bed, and that was her presentation. I'll let you take that one. I think that's the, first, if you see somebody where that's the event, they have CPVT in my mind until proven otherwise. I've seen it once in a hypertroph, but it's almost always CPVT. No comment. No comment. Scared. What a pro he is. Any other questions from the audience? All right, we're a bit past time. That was a wonderful session. Thank you to all the wonderful presentations and presenters. It was incredible. Thank you.
Video Summary
The panel discussed three cases of arrhythmias in young patients. The first case involved a boy who experienced recurrent ventricular tachycardia (VT) and ventricular fibrillation (VF) due to catecholaminergic polymorphic ventricular tachycardia (CPVT). Genetic testing initially came back negative, but later revealed loss of function mutations in triadine, a gene responsible for normal cardiac contraction. The boy was treated with nadolol, esmolol, and flecainide, and underwent left cardiac sympathetic denervation. The second case involved a newborn with bradycardia and long QT syndrome (LQTS). The baby's heart rate was initially below the third percentile, but later showed sinus rhythm with 2:1 AV conduction and severe QT prolongation. Genetic testing revealed a variant of uncertain significance in calmodulin 2, a gene involved in inactivation of the L-type calcium channel. The baby was treated with lidocaine, esmolol, and later propranolol and flecainide. The third case involved a four-year-old girl with frequent VT/VF episodes. The girl was diagnosed with Brugada syndrome, but genetic testing initially did not identify a mutation. Treatment with flecainide and sotalol was successful in controlling her arrhythmias, and she underwent focal atrial tachycardia ablation. The panel emphasized the need for continued monitoring and aggressive treatment of fever in these patients.
Keywords
arrhythmias
young patients
ventricular tachycardia
genetic testing
long QT syndrome
Brugada syndrome
fever monitoring
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