My task is to shed some light on how to, which device to choose and how to program on patients with hypertrophic myopathy. So as it was mentioned before, hypertrophic myopathy, it's a common myopathy first described by a pathologist in London with eight cases that were described using tumors and sudden cardiac death in young individuals. The fibrillators are the only way to prevent sudden cardiac death in these patients and really antiarrhythmic medications, beta blockers, calcium channel blockers are more to prevent shocks today a day. I will not dwell on this, but it's been mentioned which patients already qualify for the fibrillators. My task is to really just to see how we choose the fibrillator and how we program them. So when we decide that the patient needs a fibrillator, I think that there is the things that at least most common we need to think about it, it's that they are young patients, there is a little bit of a lifestyle issue as we heard. You know, there is how long the device and the lead would last and how long the patient will live. So when there is a mismatch, for example, that the device and in particular the leads will need to be changed multiple times because the longevity of the patients, that should help us also choose the device, I think. The need for pacing, if you need bradycardia pacing, if you need CRT, or if you need ATP, so all those things we need to consider. Also the fact that the EKG may change over time. There are studies that show that over a 10-year period, the EKG can significantly change. In appropriate shocks, it's really one of the most problematic issues in the fibrillator in this patient population. Also extreme anatomy, we need to think about it. If they have LVH with more than 30 millimeters on the wall or high gradient, and I think as you heard already in multiple of my previous talk, that patients with apical aneurysm may be a little bit of a different subset of patients and we need to think differently on how to treat them. So one of the things that comes up is do we have to do DFT testing and watch the data on the transvenous ICD or subcutaneous ICD? This is a subgroup analysis of the simple study that basically compared testing versus not testing. Half of those patients were tested, half of them were not tested, and about 4%, close to 100 patients, were hypertrophic myopathy. When you compare the hypertrophic myopathy to the dilated and ischemic myopathy, the fibrillation energy requirements were similar in both groups. If you make some sort of lead change or turn on a proximal coil in one versus the other group was not different. And finally, the number of patients that even doing that you did not have an adequate safety margin, it's the same. When you look at the subcutaneous defibrillator, this is an acute study that shows that 73 PF induction in 60 patients with hypertrophic myopathy, 72 of them were successful. All the patients with 30 millimeters or more of the septal were successfully treated. And there was one patient that did not convert with high VMI's, and I will come back to that in a second. This is our data from the IDE and the effortless study. Again, we showed that patients in this population, they have actually I think 8% of these patients out of 800 plus patients converted 95% with 65 joules versus 90%. And again, the same in patients who have hypertrophic myopathy versus not hypertrophic myopathy. The follow-up was short, so only three patients have a spontaneous episode that they all were treated successfully. This is how long it take to treat those patients and actually clearly longer than the transgenous ICD, but 94% of those patients converted in 21 seconds. That may be important in some patients with ventricular tachyarrhythmia that may terminate spontaneously. This is to show that in reality, what is important when you're talking about the subcutaneous defibrillator, it's the fact that the impedance, that's a factor of how deep you put your lead and your ICD. But if the impedance is less than 90, the success rate is certainly over, the average I think it was around 95%. If the impedance go over 110, the success rate diminish enormously around 70%. One thing that we find out in this study, which I think it's a very important point for patients with hypertrophic myopathy and just in reality all patients, it's that when the patients who have high VMI's where the lead and the device were positioned appropriately, they behave exactly the same way that the lower VMI. But the only 20% would have VMI, the device were placed correctly. The other 80% have significant issues. What about the appropriate and inappropriate shocks? Again, this is from the simple trial. You can see that patients with hypertrophic myopathy at least have this particular study, 3 or 4% of appropriate shocks. And again, around 5%, 4, 5, 6% at one year of inappropriate shock. And you can see that over and over again on patients. The also important thing to mention is that they were not different than the general population. When we look at this data from the effortless, again, patients who have hypertrophic cardiomyopathy have a 12.5 versus a 10% or 11% risk of inappropriate shock. Here, the most common cause is T-wave over-sensing. And the rate of inappropriate shock significantly decreased. It's really half when you program a second zone, a conditional zone, that really detected arrhythmia much better. This is something that I want to spend a couple of minutes because I think it's extremely important. This is out of paper of Mark who presented a couple of speakers ago that show very nicely that you have ventricular tachycardia, you have a shock, the tachycardia terminates. Here, you have a patient with ventricular tachycardia. The same ventricular tachycardia, this one, you ATP and the tachycardia terminates. Clearly, an outstanding outcome for this patient. When you look at the graph, basically, there were 149 arrhythmias. This is from 71 patients of 506 pool. But when you look at the VT episode, 36 out of 48, 75% success of ATP. This is 33 patients out of 506, so that's a 6%. You have a three-quarter success. Basically, only 5% of the patient population get benefit from ATP, which, again, if you have a patient who have transvenous ICD, clearly, you have to program that on. This study that also just came out shows that, again, 70% or so of patients with monomorphic ventricular tachycardia use ATP terminate. Some of them accelerate. Also, the problem is when you have non-sustained or when you have supraventricular tachycardia, anti-tachycardia pacing can induce ventricular tachycardia fibrillation and the patient may get shocks. This is from that paper. If you can see the patient have non-sustained ventricular tachycardia, as a matter of fact, anti-tachycardia does terminate before anti-tachycardia pacing basically induces proarrhythmia. I want to show that ATP is also proarrhythmic. This was presented already, but I want to mention that really patients with apical aneurysm are a very special group of patients because they really have a significant increase on monomorphic ventricular tachycardia, much higher than the others. Things that are unique to the subcutaneous defibrillator is that you have to have a pre-qualifying ECG. The higher your LVH, the less likely that you will have more than one vector. I think that's important. We also show that we don't need to exercise those patients routinely to select which vectors. In 90 patients we have done or so, 8 of them with hypertrophy, we didn't change vectors on any of the ones, and the T-waves and the R-waves were more or less similar. A few words on how we program those devices. If we have a subcutaneous ICD, if the patient passes, I think this is very important. Sometimes when we use it manually, you try to push to make the patient enter in this group. That's a mistake. The vector selection, you have to choose the better QRS to T-ratio, and we program the SMART pass on, and VT zone 200, VF 250. For the transvenous ICD, we use the MEDIT RIT. This is my last two conclusion slides, make a little bit of how we select those devices. For pacing, there is a group that it's easy which device you should choose. For example, if the patient needs dual-chamber pacing, for any pacing indications, you give a dual-chamber ICD. Older patients with heart failure symptoms and probably with a resting gradient of more than 50 mmHg, there is some data that shows that pacing is appropriate. If the patient needs CRT, they need to get a transvenous ICD. Patients with apical aneurysm, I think that because ATP, VT is so prevalent, ATP may be a good thing for them, and a failed SICD screening. Finally, which favor SICD in our institution, we choose it for all age. I don't think it's a good idea to think just for the very young, but clearly I think they will get most benefit. You avoid all the intravascular and the intracardiac complication. And very important, if they get infected, lead extraction, it's not such a big deal, and there is no systemic infection. When do we favor transvenous ICD? Basically, patients, I think that inappropriate shock, it's less. I think older, elderly patients probably would likely to need pacing. ATP, for example, pacing with apical aneurysm, we use on them. And the fact that I think that it's more data that shows that they do not need the VFTs. Thank you for your attention. Okay, we seem to be losing most of them. One question before Mark. What about appropriate shock interventions with the subcutaneous ICD in that data set? Appropriate? Appropriate interventions in the community, not in the lab. The appropriate ICD detection, I don't know if I understand the question correctly. No, I want to know performance of the subcutaneous ICD in aborting life-threatening arrhythmias. Okay. In the community and not in the lab. You know, clearly, to my knowledge, certainly I think that it has a little bit of a higher risk of inappropriate shock. But I think it performs extremely well when it comes to appropriate shock. Okay, but you don't have data. Mark? Yeah, well, nice job. I agree with most, if not all, of what you said. Just one comment about the exercise testing. One, I have seen that exercise testing has made patients ineligible for the subcutaneous ICD. So I still do a step test in the lab. But even more importantly, at six to eight weeks after they've healed, I bring them back and actually do a full treadmill test to look at the sensing. And almost half the time I change the sensing vector when you do a full treadmill test with the ICD in.

hypertrophic myopathy

fibrillators

device selection

subcutaneous defibrillators

ventricular tachycardia