 Texas Heart Institute educational programs on innovative technologies and techniques. I'm Zvonra Kraser. I'm an international cardiologist at Texas Heart Institute and Baylor St. Luke's Medical Center in Houston. The topic of today's presentation is prediction and management of conduction disturbances post-tavvy. I have no disclosures or conflicts of interest related to this presentation. Now there is ample evidence in the literature as far as the need for permanent base maker implantation rates after tavi that they vary tremendously based on the publication but also on the design of the device. So we can see that the incidence of a base maker implantation can vary from sapien 3 publications from 4% to lotus publications up to 37%. In general it has been reported that permanent base maker need and implantation was higher in patients with a self-expanding valve than a balloon expandable valve. So we can see that it's relatively low in the sapien 3 valves and it's higher in evolut R and lotus valve than the self-expanding valves. Now as far as the conduction disturbances are concerned and the need for a permanent base maker implantation it depends on a multitude of factors as far as decision is concerned to implant or not to implant the base maker. It depends whether the patient has a more advanced degree conduction disturbance or relatively mild whether it's type 1 or whether it's type 2 avi conduction or type 3 avi block obviously the decision varies significantly. Also it depends on patients comorbidities at baseline and therefore patients that are critically ill with a lot of comorbid conditions where a complete block hard block either intermittent or permanent might have a serious consequences will lead to earlier decision to implant a base maker. It also depends on the post-tabber pathway particularly nowadays when most of the patients are on a fast track protocol with early discharge and they stay in the hospital typically less than 24 hours. It also depends on socioeconomic factors whether there is a cost issue or whether the patient has a anybody at home that can take care of him or whether the patient leaves alone in an environment where there is no control or help in case of any emergency. And also there is an issue for a patient that live in the very remote areas where it's difficult to do cardiac monitoring as far as again decision is concerned to implant the permanent base maker. There are numerous risk factors that are known as far as risk of a permanent base maker implantation post-tabber. One of the most predictable one is the presence of pre-existing right bottom branch block which has been reported by several investigators to be the most commonly reported risk factor for the need for permanent base maker implantation. But there are other electrophysiological risk factors that play a role such as baseline atrial fibrillation that also carries a higher need for permanent base maker implantation and also presence of a conduction and disturbances such as prolonged PR interval at baseline or prolonged QRS interval also at baseline. Calcification has been also described to be very important predictor as far as need for a base maker implantation and there are a variety of scenarios as we can see in this schematic representations. We can see that significantly higher calcium volumes lead to higher incidence of a heart block and left bottom branch block and the need for permanent base maker implantation and this is particularly true for balloon expandable or sapien three valves. On the other hand calcium distribution pattern rather than the volume influence permanent base maker implantation rates in patients implanted with accurate neo valves and also we know that balloon expandable valves have a lower incidence of permanent base maker implantation than self expandable valves until recent experiences. Now when we look at a clinical impact on mortality and morbidity after permanent base maker implantation we can see that most of the investigators did not find that there are serious consequences between one and five years of follow up in those patients that receive a permanent base maker. There is only one study that is shown here where actually this was an important factor but this was done on a large volume of patients with both core valves and sapien valves but a great majority of patients had implantation of the sapien valves. So we can see that multitude of studies have shown no significant mortality impact. However as TAVR moves towards lower risk and younger population of patients who will have their devices longer this might be an important complication and might have a more serious long term consequences. When we look at permanent base maker implantation and incidence of lab butter branch block 30 days from the low risk trial such as a partner 3 trial with sapien and also evolut low risk trial with evolut pro we can see in evolut pro group that there was no significant difference in incidence of a new lab butter branch block at 30 days. However when we look at the partner 3 trial with sapien 3 we can see that there is a significant difference in incidence of lab butter branch block at 30 days where TAVR had significantly higher incidence of a new lab butter branch block than a surgical valve repair. When we look at the 30 day new permanent base maker implantation rate we can see that there is a big difference between SAVR and TAVR in evolut group 17.4% in a TAVR group and only 6.1% in SAVR group. When we look at the partner 3 trial with sapien we can see that there is no significant difference between TAVR and SAVR as far as incidence of a need for permanent base maker implantation at 30 days. Now another important issue is to look at the base maker dependency post procedure at 30 days and we can see that approximately 33% of patients with a core valve prosthesis and somewhat higher number 47% with lotus valve were still dependent on their new base maker at 30 days and this is according to reprise 3 data which tell us that a significant number of patients or somewhere between 60 or 50% do not require permanent base maker or long term basis. So an important thing is to be able to find out who or which patient will be permanently dependent on permanent base maker and that at the present time is still unknown. There are other risk factors that predict the incidence of a permanent base maker implantation and one of them is implant depth. The deeper the implant is the closer to the conduction system the higher the incidence of need for permanent base maker implantation at 30 days. Now this is a very interesting and very very important information and this is from a core valve evolut R and they will pro low risk patient trial which showed a tremendous variability in permanent base maker implantation rates and we can see here that the highest volume centers reported remarkably low 1.9% permanent base maker implantation while some of the centers reported very high rate of need for permanent base maker close to 30%. So what is the reason for this tremendous difference in the need for permanent base maker implantation? Is it a learning curve? Is it a specific technique? Is it a patient selection? That is an important question to answer. Now we know that self-expanding devices or timer devices traditionally in the past carried a higher risk for permanent base maker implantation. There is a recent study from NYU Langona Health group that examined the use of minimizing depth according to the membranous septum length approach with evolut R and evolut pro valves and they published this in the American Journal of Cardiology in 2019. They called this approach a Midas approach, minimizing depth according to the membranous septum length. What they have found as far as univariate and multivariate predictors are concerned, again the right or bottom branch block was the highest predictor as far as need for a base maker implantation. But another factor that was very important was the membranous septum length than less than five millimeters particularly if it is three millimeters or less in length and that was also a reliable predictor. Larger valves such as evolut 34XL also had a higher incidence of a complete heart block. But another factor is implant depth that is more than the length of membranous septum is also a very reliable predictor. So in their results and their conclusion they stated that a permanent base maker implantation rate reduced in their experience before using Midas technique from 9.7 percent to 3 percent with the use of new Midas approach. Not only that but they also showed the incidence of a new left-bron branch block decreased from 26 percent to 9 percent using Midas technique. So this technique is being embraced by a lot of operators because it has been shown to be of great benefit. So how to achieve this technique Midas technique obviously we have to know the length of the membranous septum that can be obtained from the CT and also with the use of so-called the CUSP overlap view that isolates the non-coronary CUSP by overlapping the right coronary CUSP and left coronary CUSP and this is generally the best achieved in RNO projection. We know that the membranous septum is the closest to the non-coronary CUSP. So if we have the information on the length of the non-membranous septum then we can easily measure the distance during the valve deployment looking at the non-coronary CUSP. But this view provides us a good anatomical reference where to deploy the valve in relation to the non-coronary CUSP because also this view elongates the authymal tract in a long axis view and helps us in being able to see the best the true length of the membranous septum. It also removes the parallax in the marker band and assists with depth visualization near the non-right curvature and the membranous septum during the deployment. But it is very important when you use those techniques that you should be able to obtain high quality Gainty CT with contrast and this CT has to be free of movement artifacts and slice misregistration. Here are the examples of deployment of the self expanding valve with CUSP overlap technique. Here we can see in this image that the CUSPs are still not overlapped you can see the right-coronary CUSP separated and the right-coronary CUSP left-coronary CUSP and non-coronary CUSP and they are not at the same level. So in this particular view, when we rotate the patient to a 13 degree RAO and also a little bit of color view we can see the non-coronary CUSP and overlapped left and right-coronary CUSP and we can see the device is probably no more than a millimeter below the non-coronary CUSP and then with further deployment, slower deployment, flowering we can see the device is stationary it's not moving downward and it's in very close proximity with the yellow dot that indicates the lowest part of the non-coronary CUSP and finally we can see with a valve deployment the optimal deployment of the valve with satisfactory results. So slow deployment starting in a supra annual level allows the valve to descend to its target position with minimal catheter manipulation and the final result is shown here probably two millimeters below the lowest part of the non-coronary CUSP. This technique therefore minimizes the risk of interaction with the conduction system. So in summary, as far as predictors and management of conduction disturbances post-tabber of concern, we have seen from published information that right-bundle branch block at the baseline is one of the strongest risk factors and predictors for the need for pacemaker confrontation post-tabber but also atrial fibrillation prolonged PR interval and prolonged QRS are also playing a significant role as well as a landing zone and calcification that also leads to higher incidence of permanent pacemaker implantation. New onset left-bundle branch block post-tabber has been associated with higher mortality and reduced left ventricular ejection fraction recovery post-tabber. Permanent pacemaker implantation rates vary between institution but also between operator and as far as publications are concerned for all valves. However, the newer information particularly related to the implant depth and the CUSP overlap technique and using MITRE's approach and measuring the distance and from the membrane septum to the non-coronary CUSP or the length of the membrane septum can certainly help us in reducing the incidence and the need for permanent pacemaker implantation post-tabber. However, more research is still needed to identify patients who may not be fully dependent on a permanent pacemaker after a month or a few months of follow-up and that will certainly be an important factor to determine. Thank you very much.