All right, so I'm going to talk about how to place a transvenous pacemaker through the floor of the pulmonary artery through a left infraclavicular pocket without using separate access from the SVC, and we'll discuss that relevant anatomy. Other than the fact that this work was done when I was at the University of Iowa, I have no other relevant disclosures. Here's a brief patient history, 18-year-old male, hypoplastic left heart syndrome, has undergone stage palliation, he's had an intracardiac lateral tunnel. The relevant history for us at four years of age, a dual chamber epicardial pacemaker was placed for sinus node dysfunction with intermittent AV block at 10 years of age. His fenestration was closed, which is not infrequently done at 14 years of age, and obviously that's not directly relevant other than you cannot use the fenestration that existed to place your lead. At 14 years of age, a second LV lead was added, the goal being resynchronization, and this was also epicardial. When he was 15 years, so a year later, both of his ventricular leads failed, and the op note said that there were dense adhesions, very few adequate epicardial pacing sites. They did manage to get a lead on at that time. Then at 18 years of age, he had progressive increase in his thresholds. The pacemaker was at end of life, and the question that was brought up was, what do you do now? So from the decision-making standpoint, we had a multidisciplinary discussion. Dr. Wall, who you just heard from, was our electrophysiologist at the time. We obtained a CTA to determine feasibility and anatomical relationships and decided to place an endocardial system using a standard left pre-pectoral pocket, which is how they typically will put in pacemakers in normal anatomy. Then the atrial lead, since this is a lateral tunnel fontan, it can be placed into the lateral tunnel. There is atrial tissue. Then the ventricular lead, the plan was to use the floor of the pulmonary artery to enter the atrium so you did not have to have a separate access site and tunnel the lead, which obviously can be challenging with potential for lead injury. Obviously, this is the paper that everyone votes. Dr. Mehta just presented this information along with his mentor at the time, Dr. Giovanni. Just to remind people, if you come from the SVC, the floor of the pulmonary artery is adjacent or close by to the common atrium. Even though we call this the left pulmonary artery, it really is the native RPA, and we know that relationship based on echocardiography. This is a cartoon showing what our patient had. The patient had a lateral tunnel fontan. The goal was to puncture the floor of the neo-left pulmonary artery. Here's an LAO projection showing that there is a potential space here. You can't just perforate. That knowledge is necessary. I'm going to go through some videos here to actually show this. From the standpoint of access and equipment, we went in from the left femoral vein artery and the left axillary. That was the site where the pacemaker was going to be implanted. We routinely are able to, especially when you have right ventricular morphology, are able to get back retrograde across the common AV valve from the arterial approach so that we had a catheter in the pulmonary venous atrium that would allow us to take pictures. Then we used a steerable channel sheet, and I'll just briefly show you what the different sheets available are, and then a coaxial system, which I'll discuss as I go through the angiograms. Here are the three sheets that I know that are available. These are all steerable in that you can make them change the approach, even though you are approaching the vessel from a different site. We used the channel sheet from Boston Scientific, but Abbott also has the Gillis sheet which can be used, and then the Oscar Destino twist sheets. These are very interesting because they do come down to six and a half French internal, although remember the OD is still larger. Then this is our patient. Here's the angiographic landmark. Here's the frontal projection. You can see the floor of the pulmonary artery. This catheter is in the pulmonary venous atrium. You can see it's actually in the pulmonary veins, and so that intended site of puncture will be over here. On the lateral view, you will see that potential space that I just showed you earlier, and this will be the trajectory for the approach. Now, as you might have read from Dr. Mehta's paper, the goal is to approach from the SVC because you need that directional approach, and especially if you're using a transeptal needle, if you come from anywhere else, the approach will not work. What we did is we used the deflectible sheet to simulate an approach from the SVC so that we would get the same trajectory, but even if you do this and put a transeptal needle, it still will not work. What we did then is we used the RF wire so the deflectible sheet maintains your approach. We used an RF wire through a coaxial system using the vertebral catheter, which is what we used. You can use any angled catheter, and this is the first application to perforate the floor of the pulmonary artery. Now, as you saw, there is a potential space. The RF wire wants to travel in that potential space, and you see this in the angiogram demonstrated here. Obviously, if you continue down that direction, you're not going to get the correct spot. You have your marker catheter sitting in the atrium. The next step, the coaxial system, meaning the vertebral catheter inside it, we are able to redirect the RF wire. This is the direction it is going to go to. In the next scheme, these are all LAO projections. In the next, you can see the lateral projection here. The RF wire during the next energy application crosses the roof of the atrium now and enters into the pulmonary venous atrium, and in the frontal projection, this is what it looks like. Note that there is a fair distance here. Some of it, which we have created as we pushed the system through, but also there is a distance, so keep that in mind. Then next, steps are fairly straightforward. You want to advance the wire through the micro catheter through which you have advanced the RF wire. Once that is across, you use a coronary balloon to dilate this track so you can get the sheet across. As you have seen in the previous presentation, some people will put in a covered stent or a diabolo stent over here. Given that we were going to place leads, we elected not to actually put anything in, but simply advance the delivery sheet for the lead. Next here, what we did is we used a stirruble select sheet through which the facing lead would be advanced. Initially, it was advanced into the atrium, position confirmed on fluoroscopy. We then used a wedge catheter so that we would have a balloon-tipped catheter to cross the systemic AV valve so we would not incorporate or get entangled in the tricuspid valve tissue. Then advance the catheter into the ventricle defined over here. The next steps were fairly straightforward. The EP colleagues took over, Dr. Law at the time, placed the transvenous sheet into the ventricle on the septum. You can see there is a loop left behind so that we would have less tension on the tricuspid valve. After that, he placed an atrial lead seen at the other marker over here, which was in the lateral tunnel fontan. This is one way to approach placement of the transvenous pacemaker. By avoiding another access site, you're avoiding either smearing or putting the pacemaker pocket in the right intracavicular approach. As I was getting ready to make this talk, I just want to put in a plug for this paper. Shivkumar Sharma from India actually has written a very nice paper on the variety of different approaches you can use for placement of pacing leads in the fontan population. For those interested, I would urge looking at this, published out in 2019. It's a very good paper.

transvenous pacemaker

pulmonary artery

left infraclavicular pocket

hypoplastic left heart syndrome

steerable channel sheets