Hi, this is Eric Prystowski. Welcome to another episode of EP on EP. And I'm actually delighted to have our guest with us today. It's Yongmei Cha from the Mayo Clinic, and she is consultant professor at the Mayo Clinic. And she has a bit of a minor job called the director of the device clinic. And I'm guessing they have more than a couple of devices at the Mayo Clinic. So Yongmei, welcome to the show. Eric, thank you. I'm so grateful to join you today, though. Thank you. I'm really looking forward to this because of your expertise in an area that I struggle with at times, which is how to optimize CRT therapy in a patient who comes back. But I think the first question I'd like to ask you is, I'm guessing that the best optimization is to pick the right patient. So why don't you educate us on where you are now with the kind of people you would select for CRT therapy? Well, Eric, that's a terrific question. I think in my mind, I usually set up a few key points, starting with the patient selection. Then during the procedure, how to make sure your lead placement can achieve the best outcome. Then it's the post-implant, how are we going to do, what we should pay attention to to improve CRT response. So pick up the right patient is very critical. So this is why current CRT guideline is pointing out to the patient, and then the key here is the ECC criteria with the lead bundle branch block morphology and wider QRS duration. So overall, we haven't seen your patient with a lead bundle branch block, especially if it's typical lead bundle, and with a QRS duration greater than 150 milliseconds. But note sometimes in females with dilated cardiomyopathy, so their QRS duration may only 130 or 140 milliseconds. But because of lead bundle branch block, all these patients are considered good responders. And also the meta-analysis, a lot of clinical trials have been proven this important criteria with the wider QRS duration and the lead bundle branch block. So that's a great start. Let me just tell you, I had a patient the other day that I wrestled with in my own mind a little bit, because they did have a non-ischemic cardiomyopathy and an EF around 25 to 30, and they had a right bundle, but it was a pretty broad right bundle. It was about 175 or 80 milliseconds. When do you think it's a good thing to do, or what kind of patient with a right bundle would you consider for CRT? Okay. So based on the current guideline with the HA, CCA, HRS guideline. So if your patient and your function class is three, with the patient like you mentioned, very wide QRS, but right bundle branch block, and then there will be class 2A indication. But if patient's neural function class 2, then the patient will be 2B indication. So in that regard, so I look at the right bundle as this. It really depends on patient who has underlying the lead bundle or left ventricular conduction delay or not. So some patients have pure right bundle branch block, and this patient responding rate probably with that wide QRS from our institution experience is probably 30%. But if patient who does have underlying left bundle branch block, but the right bundle conduction more delay than the left bundle. So of course, ECG shoulder right bundle, and this type of patient may have some response. So I think that there are two kinds of patient with the right bundle branch block presentation. That makes a lot of sense because if you just think electrocardiogram, like electrophysiologically, if you just had a pure right bundle and nothing else, you wouldn't have a QRS duration of 175 milliseconds, right? I agree. Yeah. So that's a really good point you're making. Are there people you wouldn't do? So let's say you take a person who's got a left bundle and the QRS duration is 160 milliseconds, but they have ischemic heart disease and you do an MRI and you find a big scar on the lateral wall. Is it still worth it to give that person a chance or are there any ischemic sort of patients where you would say, you know, the outcome is really not going to be that good to go put the device in? How do you look at that problem? Well, this is a very good point, Eric. Yes, I think of the clinical trials and the clinical practice, we have seen the patient with the dilated cardiomyopathy, you know, usually have a better outcome than the patient with ischemic cardiomyopathy. But having said so, if a patient has a large scar and ischemic etiology, but has a good left bundle branch block morphology, I would provide the patient with the CRT because yeah, even though they may not, the responder rate may not be as high as DCM, but in this group of patient, I haven't seen good responders. So I would try. Okay. So we're now going to go to the next part of what your, your three-legged stool was you started with. So now we've picked just the right patient and I'm sure you've had the same discouraging moment that I've certainly had, where they've been a woman, a DCM, I mean, everything looked great. You're kind of anticipating a real bump up in EF and a decrease in symptoms. And they come back three to four months later and they're feeling better, but you know, not knock your socks off better, right? They're, you know, they're sort of, you almost think sometimes they're just trying to make you feel good because they want to tell you they're feeling better. And you go do a functional study and your EFs move 5%. What's what's, what do you do next to see if you can change that, that situation? Yes, I, I think sometimes the way of stopping here is the patient that you have only going up a 5%, but that can be the variation just by different readers, right? By, you know, from the echocardiogram standpoint. So, and then plus combine it with a clinical neurofunction class, the six minutes walk, you know, it's really not much improvement. I think usually what I do is a stepwise. So the first step usually I do is just look at the underlying condition. Is there anything missing? For example, some patient who are taking the beta blocker and AC inhibitor, for some reason blood pressure dropping, and then patient may reduce the dose or stop, you know, somehow, you know, volume overload is another component. I think in this kind of patient, you have to think about that the whole package and then look into the other possibility. Then the next step I will look into how many percent this patient is biventricular pace. So that's a very, very important step because the biventricular pacing, we really want to achieve 100% or 99% biv pacing. The reason is one third of patients who receive CRT, they have atrial fibrillation. So their ventricular rate can be very high over your baseline pacing rate. And they may deliver pacing, biv pacing, but it's triggered pacing. So in that case, we need to provide a higher dose of AV blocking agent or may do AV node ablation. The AV node ablation process, many studies have shown, you know, even though after you ablate the AV node, you do achieve a great improvement in clinical symptoms and survival. So this is a very critical step. And another thing as an electrophysiologist, we know the patient with the cardamom, they have a lot of PVCs. So sometimes multifocal PVC that you need to give antiarrhythmic drug or unifocal PVC, we take the patient to the lab for ablation if the burden is over 10%, for example. So these are important, you know, to suppress the, to really control the ectopies or irregular heartbeat. And in this way, we can achieve as high as possible for the biv pacing. So that's a terrific checklist. You know, a lot of people forget some of those things. It's always good to go back to basics, right? But let me make your life a little more miserable. So let me give you a situation where none of those were there. So you got a patient who came back and they're maybe not 100%, but 95, 96%, no AFib, no PVCs. It just isn't doing it. Is there, I will tell you, I've been very disappointed over the years with all these things people say we should do, like using the echo optimization and all that. I've honestly been a bit disappointed, at least in my own center. What do you do? And I will say, it's not all those things which are terrific checklists. It's actually someone where everything should have gone well, but it just didn't. Is there something else you can do? Yeah, I agree with you. I think for the AV and the VBA optimization, the multiple trials and the studies has shown a neutral effect. It's not really superior than the standard programming. So the other things I would look into that is if we do have a good LV lead location. Even though we know we want to put the lead on the lateral wall, and then maybe the CRT, those clinical trials, has not shown much difference with the lateral wall pacing compared to the anterior interventricular pacing. But having said that, it's very important to pay attention to is to make sure the pacing is on the mid-ventricle and the basal ventricle, not the apex. So I think sometimes we thought that we like to pace the pole one, but often the pole one is on the apex. So that's why we need to look into these details, to look into the configuration if we can change. I have some patients when I change the configuration to more towards the basal, and if a capture threshold is still adequate, and then they do have improvement in terms of injection fraction. Yeah, that's good. I like that. I've sometimes also, I don't know if it's useful, I've sometimes hooked them up to a 12 lead and then played around with timing of the VBs to see if I can optimize it. But I understand the research there has been mixed, but sometimes you're left with nothing else to do. You figure it's worth a shot, right? So is that something you will occasionally do too, if you- We do. Yes. So if a patient, even though the overall trials are not show apparent, a better outcome, but individual patient may be different. We sometimes do echo guide, if patient is totally non-responder, there's no other reason. Any other factors we can look for, we do individualize the VB or AV optimization. And then some patient, even they are sicker, on the transplant list, we bring them to the hemodynamic lab. We pull the swine in. We even do the AV, VB optimization, depend on their hemodynamics. So the blood pressure and the white pressure, LV, LV diastole pressure, and then to adjust the AV, VB delay. But Yangmei, this was a fantastic review of a very common situation that we all get with. And I can't thank you enough for providing your expertise for our listeners. And I wish you well and stay healthy. Yeah. Thank you, Eric. Thank you for the opportunity joining you. Thank you.

CRT therapy

patient selection

left bundle branch block

wider QRS duration

troubleshooting