Dr. Mitrany will present the final case of this session. Thank you for inviting me. It's an honor to be here. So my case also has to do with cardiomyopathy. This is a 40-year-old asymptomatic gentleman with an incessant narrow complex tachycardia found incidentally on a pre-employment history. He's an interesting guy. He's a professional minor league baseball coach. So he doesn't run around that much, but he has to do some physical activity to keep up with players in their 20s. So he had a new onset cardiomyopathy when they did the ECHOs. The F was around 15% to 20%. He had a prior electrophysiology studying ablation, which was reported as a fascicular or junctional tachycardia with VA dissociation that was suppressed but not terminated with ablation in the metadistal third of the fascicular system. And the prior ablation resulted in a right bundle branch block. So he was referred to us because they wanted us to try cryo, and they felt it was a high risk for heart block, and they wanted us to place the appropriate device, which was the expectation was that he would need a device. On ECHO, he had normal OV size. His EF was 15% to 20% severe global hypokinesis. And again, he was asymptomatic. If you questioned him, he was clearly class 2, though. And this is telemetry. He did this all day. He would have sinus rhythm beats, and then go right into this narrow, complex tachycardia, which was incessant. So this had all the markings of a tachycardia-induced cardiomyopathy. So the issues for experts, and we can go into it one at a time, is this tachycardia-induced cardiomyopathy? Or did he perhaps develop a cardiomyopathy that preceded and caused the tachycardia? And that's always going to be a question when you have patients with tachycardia-induced cardiomyopathy. What is the optimal treatment in this patient? Well, clearly, it's going to be guideline medical treatment for the cardiomyopathy. Should we do pharmacologic control of the arrhythmia, because he already failed one ablation and used amiodarone, but he's a young guy? Another attempt at catheter ablation, which was what he was referred for. If a device is needed, what kind of device? Clearly, or maybe not clearly, we would want a physiologic device. Should we do CRT or his bundle? And we'll talk about that a little bit. And since the premise is that this is a tachycardia-induced cardiomyopathy, does the patient require an ICD if he gets a device? A lot of tough questions. Oh, good. I thought there were. I didn't want to give you easy questions. So let's do it one at a time. So he was referred for ablation of the AV junctional tachycardia. As AV block was an expected outcome, he was also referred for placement of an ICD. So the five choices, we can ablate the tachycardia if AV block implanted, DDD, CIED. And we're not going to deal with the ICD issue on this question. Ablate the tachycardia if AV block implanted by VCIED. Ablate the tachycardia if AV block implanted his bundle pacer. Clearly, the choice all of us want is ablate the tachycardia and don't get AV block. That should be our marching order. But I'm going to take that choice away. So it's not a choice now. Or just use the amniotic around. But I'm going to take that choice away also. Well, it's easy to take the amniotic around away. Because even if it's a third time or fourth time, this patient deserves a shot at a cure. I think most likely this is tachycardia-induced chromopathy. I think it's always impossible. Well, not always. But often it is impossible to be 100% sure. But I think you explained to the patient that you think he has a tachycardia-induced chromopathy. I think you're probably 90% sure. And it's a relatively young person. You do an MRI. Make sure the patient doesn't have any score. So if the MRI doesn't show any score, then more likely than not, it doesn't show evidence of myocarditis or sarcoid or anything else. And you probably have a tachycardia-induced chromopathy. And you could take that choice away. But I mean, your job is to cure it without getting heart block. I've done a couple of these jets. And you do sort of bite your lip when you're doing them because they're scary. Because my experience is that they're almost always near the AV node His bundle. They're not typically distal in the conduction system. I mean, I guess you can have an automatic fascicular tachycardia. But you have to go back and look at all the records. And the patient got iatrogenic right bundle branch block. But before that, they didn't have a right bundle branch block. And most likely, they had a narrow, I mean, if you get some of the strips from before, they had a narrow QRS. So a narrow QRS doesn't come from a fascicle. It comes from the AV node His bundle region. And I think you can do it with RF. You can do it with cryo. Cryo is most forgiving. But the goal is to terminate the tachycardia. And then, if you get unlucky, and this literature is primarily a pediatric cardiology literature. And none of these are like 40 or 50 patient series. They're usually five patients, 12 patients. Only a small percentage of the patients end up with pacemakers. So we may not even have to talk about what type of device to implant in this patient. Sure, but you want to talk to the patient beforehand that he may need a device. I think you tell the patient they may need a device. Which one would you do? Well, I would probably put a pacemaker in this patient. A regular IRV pacemaker. Well, I think, again, he's going to have a tachycardia dyschromopathy. But if you get AV block, I think you can argue for a BiV pacemaker. You can argue for a His bundle pacemaker. I suspect, though, however, you're going to be ablating near the AV node His bundle. So you're most likely going to have to do a left bundle branch lock pacemaker. And at the end of the day, a QRS duration of 120 to 130 is probably better than what you'd get with a BiV. But you can say, well, there's not five and 10 year follow up on left bundle branch block lead. So I think you can make an argument for putting a left bundle branch block lead in and putting an LV lead in. If you really mess up the patient's conduction system, he's going to be dependent. He's 40 years old. And this way, you have two physiologic leads should one fail in the future. And he's 40 years old, and he's active. So the chance of a lead failing over 20, 25 years, the pacemaker lead is 5%, 7%, 8%. Do you think it's wrong putting in a standard EDD pacer? We were trained around the same time. Back in the 90s, when people were ablating AV nodes, there was no CRT or His bundle pacing. And studies showed at that time, EFs improved despite the fact that patients were desynchronized. Yeah, well, that's true. Except I don't think the studies were as rigorously done. And I think you always want to do the very, very, very best you can for a patient. So you can put a dual chamber pacemaker in as long as the ventricular lead is in the conduction system. I think that's fine. But we know that over many years, patients develop cardiomyopathy. They may not have florid heart failure, but they develop LV dilatation. LV and systolic diameters increase. And 10% to 15% of people over five years to 10 years are going to develop a true cardiomyopathy, and maybe up to 20% over 10 years. So he's 40 years old. I think it would be hard to argue. And that may have been OK 15 years ago, but I don't think it's OK now. No, no, I agree for sure. But now here's the other question. Since we think it's a tachycardia-induced cardiomyopathy, if he requires, and again, it's a big if. Obviously, we're all going to try to ablate this without causing heart block. Should it be an ICD? I think it's a hard question. If someone said, I'm going to put in a Bi-V pacemaker, not a Bi-V ICD, I think I wouldn't consider that wrong. If you go by the guidelines, you can say, well, the guidelines say this patient has a low EF. But you can also say, you think it's most likely reversible cardiomyopathy. Maybe not completely reversible, but you can make arguments for a Bi-V pacemaker because you feel so strongly it's a reversible cardiomyopathy, or at least a conduction system lead. And you can make arguments for an ICD and say, well, when he comes back eight or nine years later and his EF's normal, then you don't have to replace it or whatever. So I think it's a tough question. You wouldn't have brought it up here if it were easy. And I think there are a lot of right things to do. All right. So the first issue definition is heart-induced cardiomyopathy is we have to rule out any other cause of non-ischemic cardiomyopathy. So that's a check for this patient. Absence of LVH and relatively normal LV dimensions and absence of significant LV dilatation. We did not do an MRI because the timing didn't work out when he was referred in. But so far, I agree 90-plus percent that this is tachycardia-induced cardiomyopathy. The fourth one issue would be recovery of LV function after control of tachycardia. So for that, we have to wait and control his tachycardia. Recently, a position paper came out on tachycardia-induced cardiomyopathy. There are various molecular mechanisms, including decrease in the beta-adrenergic receptors in terms of number and sensitivity, oxidative stress, depletion of myocardial phosphate energy stores, and a hypertrophic response during recovery from the tachycardia-induced cardiomyopathy. There are hemodynamic factors, decreased myocardial blood flow, decreased filling time, cardiac desynchronization at the interventricular level, and atrial contractile dysfunction, loss of atrial contraction. And of course, there's always neuro-humoral effects whenever you're talking about cardiomyopathy, similar to other types of cardiomyopathy. Typically, if you catch it early, you're not gonna see the dilatation, which was the case here. But if it goes on long enough, patients clearly can dilate. In terms of treatment of tachycardia-induced cardiomyopathy, on the left side, this is for patients with AF, which is the most common cause for tachycardia-induced cardiomyopathy. For the right side, they say control the rhythm, which is basically the crux of this case. So antiarrhythmic therapy with amiodarone is part of this position paper, and consider ablation for persistent arrhythmia. So again, for the consensus statement, we have to rule out other causes of tachycardia-induced cardiomyopathy. Management includes standard heart failure therapy, rate control in the case of AFib, and rhythm control for other arrhythmias. Ablation may be preferred for rhythm control for persistent or repetitive atrial ventricular arrhythmias, even when asymptomatic in patients with tachycardia-induced cardiomyopathy. And the tachycardia-induced cardiomyopathy usually resolves with resolution of the tachycardia. There is a long-term risk of sudden death, which plays into that issue of, if he needs a device, should we put a defibrillator? There's one study that showed some long-term abnormalities in structure and function, including MRI finding of diffuse fibrosis. It's not the delayed enhancement you see with gadolinium, kind of a more diffuse process. And there are reports of sudden death in patients who have relapse of their tachyarrhythmia, and this was correlated with a subsequent decline in EF. In this JAK review of patients with heart failure and improved ejection fraction, and this is an issue we all face, of course, when we have patients with defibrillators and normal EFs who never had shock, we always face the issue, because they had a cardiomyopathy, are they still at risk for ventricular arrhythmias and sudden death? And according to this schematic by the authors, if patients truly have normal recovery, normal biomarkers, normal trans-thoracic echo, absence of heart failure, I think they can be considered in terms of normal recovery. But other patients may have partial recovery, which you kind of alluded to when you were discussing this issue, that they may still have some residual LV dysfunction. So this is an anatomic paper that showed the differences in the AV node and his bundle and the penetrating bundle in the muscular skeleton. Given that this patient had ablation that resulted in a right bundle branch block, in a patient like this who requires conduction system pacemaker, does prior ablation play a role in your thinking of whether to do it or how to do it? And given the anatomic variability that we may see in the AV node and penetrating AV branches? Well, I think it's gonna depend upon what you find when you do your EP study. So would you map this area then? Yes, obviously that's the area you're gonna be working in. Okay. So permanent his bundle pacing, I think I'm gonna skip these slides because this group all knows that his bundle pacing has been shown to be superior to RV pacing in various subsets. And there have been a few studies, including a study presented this morning, late-breaking comparing his bundle pacing with CRT, but that's not the gist of this study. And there are some potential pitfalls and concerns of his bundle pacing, but let me just move on to the next topic, which is what did this patient have? So this is another EKG on this patient. You see his right bundle branch block. And then you see premature complexes, still with right bundle, but clearly aberrant compared to the baseline. So if this is his baseline, this is the premature complex, which was called junctional, which is slightly aberrant. Just stop me if you have any thoughts. Well, I mean, you almost see group beating like that. You always have to worry about a two-for-one, non-reentrant supraventricular tachycardia due to going down the fast pathway and then the slow pathway. That's what I always worry about. So we truly have a master here. And if you look at the intercardiacs, the atrial are not dissociated from the ventricles. If you follow it long enough, it's a one-to-two pattern of the A to the V. They never dissociate. There's never any VA conduction. The activation is a high-low right-to-left pattern. So the EHs for the short or the fast ones stay constant. The VHs also stay kind of constant, so they are linked. It's not a dissociated pattern. It sometimes looks junctional, like in this complex. You see the HISS leading, and here it's conducting just down through the slow pathway. In this, I'm showing you the AH of the slow pathway. So one of the features for a non-reentry dual AV nodal tachycardias would be the slow pathway is really slow, not just in the 200 to 300 millisecond range, but very slow. Also, VA dissociation is a feature. So here we're actually pacing the ventricle faster, and we can never get VA conduction. This just shows we tried to induce AVNRT, and it wasn't inducible. We had a lot of competition from the two-for-one induction. Which is typical in this, because their retrograde conduction is so horrible that that's all they get is the- Exactly. So this is another tip off. We actually never got true AVNRT. So we did use cryo, because he was referred for cryo, and cryo's an acceptable slow pathway method. Well, don't you do that sometimes? Give the customer what they want, and we'll do what's best for the patient. But I think cryo is just fine. Would you use a six millimeter or eight millimeter? Six. Yeah, cryo, I mean, clearly we're gonna do what's best for the patient. Cryo's as good as RF for AV node reentry. It just takes a little bit longer, and slightly increased risk of coming back. But actually, when you think about it, it was a smart thing to do. This patient's had a lot of burning already. That was my thinking. And the great thing about cryo is, with a six millimeter catheter, it's almost impossible to get heart block. If you get transient heart block, conduction will come back in five minutes, three minutes, 10 minutes. So it's very forgiving in this patient. Right, and my thought was, because even though we had a right bundle, and the HV looked normal, I wasn't really sure where all the lesions were placed. So I thought we'd go there. Plus the referring one to that. So the features of dual AV nodal non-reentry tachycardia, single P wave conducting down both the fast and slow pathway. There's a wide disparity of the AH intervals, like we saw in this case. Lack of VA conduction. Lack of inducible AVNRT. It's often misdiagnosed. 48 out of 68 cases were misdiagnosed on one review. It's led to ICD implants, as well as pulmonary vein isolation. And it is a rare cause of tachycardia induced cardiomyopathy. So in follow-up, his EF improved to 45 to 50% one year, and 50 to 55% 18 months. He was treated with low-dose beta blocker for diagnosis of heart failure with improved EF. And he's coaching, unless the Marlins, unless he was fired. You know, the managers get fired a lot more than we do. That's a great case. That previous slide, I think, is a great summary of everything. We actually published a paper about AV node reentry, how commonly it's picked up in devices. And I won't forget, you know, Mark Josephson, a couple years before he died, presented at a meeting almost an identical case of a patient who was referred to their institution for like a heart transplant, due to, or EP study, but had really pretty severe heart failure, and had incessant SVT like this, and that's what he turned out to have. And so it's important to keep that in mind. And people also get referred, it's a misdiagnosis having a fib, and he missed a group meeting. So that's a great case. Thank you. Any questions or comments from the audience? If not, I will thank the presenters for presenting excellent cases, and our master for the excellent discussion, and feedback. And thank you for joining us. Thank you.

cardiomyopathy

tachycardia-induced cardiomyopathy

ablation

device placement

CRT

individualized treatment plans