Welcome, everybody, to Core Concepts 2022. I'll be talking again about intracardiac ultrasound in EP. These are my disclosures. So topics of discussion today, we'll go over some basic imaging concepts and catheter design. We'll be talking about both two-dimensional and four-dimensional ice probes. We'll talk about how to obtain basic ice imaging views from the atrium and ventricle. And then we'll speak about using ice in atrial ablation, followed by left atrial appendage occlusion, and then ventricular ablation. And then we'll close with some slides regarding the prevention, management, early recognition of procedure-related complications. So just some basic ecophysics. This will be repetitive for people watching, but I think important to highlight. Ultimately, with ultrasound imaging, we're passing sound waves into tissue. And that tissue, whether it's blood pool or cardiac tissue, will have variation in the impedance of that particular medium. So when the ultrasound waves impinge upon a substance with different density or acoustic impedance, some of that ultrasound wave gets reflected back and will appear bright. So the more dense an object is, the brighter it will look with ultrasound in general. When we're optimizing imaging, there's an interplay between how much you see and how well you see it. So how much tissue you see is largely a function of wavelength. So the deeper the penetration of the ultrasound beams, the more depth that you will achieve in your field of view. And because wavelength is inversely related to transducer frequency, when we want to see more, we need longer wavelength, therefore lower transducer frequencies. This is balanced by changing in frequency affecting tissue resolution. So this is, on the bottom left here, a stylized view of the phased array probe. So you're emitting a 90-degree sector of imaging in two dimensions. Each of these lines is the line of resolution. So the higher the frequency, the more lines of resolution you have, the greater the resolution of the image that is produced. So in general, if you want to image effectively, you want to maximize resolution and you want to image as closely to the object of interest as possible. Sometimes this is practical and sometimes it's less practical. Here's an example of imaging in the mid-right atrium. This is the home view imaging through the tricuspid valve. And you can see same patient, same transducer position, the left at 5.5 megahertz and the right at 10 megahertz. So the lower frequency image on the left is brighter and you can see further, albeit at the expense of adequate resolution. Imaging platforms, 2D imaging platforms. This is the radial eye system. I show it now almost more for historical interest than for practical consideration because it's very infrequently used in clinical practice these days. But the original design is a non-steerable nine French, nine megahertz fixed transducer that's mounted on a catheter that is generally placed via a sheath, either a steerable sheath or a curved sheath. And the imaging plane is perpendicular to the long axis of the catheter offset by 15 degrees. So its original application was in transepal puncture. And here on the upper right, you can see the imaging catheter in short axis and the tip of the transducer needle tenting the fossovalis. You can see pretty good definition locally of the fossa and the superior and inferior limbus, but fairly poor definition of the lateral aspects of the right and left atrium. So really for this to be used for diagnostic purposes, you have to move the catheter close to the area of interest. In contrast, phased array probes are much more versatile. The design of the catheter is typically, and there are a variety of different ones, but typically they have multiple different degrees of freedom. So they can be flexed, they can be anterior posterior flexed, left, right. You can clock or counter clock, you can insert or withdraw. So you have eight degrees of freedom for these particular probes. And it's important to have that freedom because the image in contrast to the radialized is parallel to the long axis of the catheter. So you can see here in the middle, the imaging 90 degree imaging sector, which in this case is again oriented through the tricuspid valve, needs to be moved. So whatever area of interest, you have to adjust the position of the probe in order to see it. As I said, a very versatile imaging platform, you can vary the transducer frequency. You can vary your field of view up to 15 centimeters, and it has full color and spectral Doppler capability. So in addition to anatomical data, you can get physiologic data. With any imaging modality, it's good to have the standard frame of reference. So as was alluded to, the home view is a view with the imaging transducer placed in the mid right atrium. And here we're imaging through the tricuspid valve. That's a fairly anterior slice because you can see here a slightly tangential view of the aortic root and the alveolar tract. This is a natural position of the catheter if you just place the ice catheter into the right atrium and is an important frame of reference, particularly when we're imaging in the atrium because most of the atrial imaging planes can be obtained from this position with very little movement of the catheter. Here's an example of that. So you can see here a series of images that are oriented in sort of a clockwise manner where we begin in the home view. And what we're doing simply is clockwise rotating the imaging transducer. And so what that will achieve is a slightly more posterior, lateral posterior orientation. For atrial imaging, again, we start by imaging the right atrium anteriorly through the aorta. We go more posteriorly here. Now we see more of the aorta and the tricuspid valve foreshortened. Now we're imaging through the fossa and inferior limbus. You can see the left atrial appendage in the far field and you start to see the mitral valve. Further, clockwise rotated. Now we see the left pulmonary veins and the aorta. More posterior, posterior wall of the left atrium, esophagus. And then further, now we're 180 degrees essentially from our home view and we're looking back at the right pulmonary veins, superior and inferior. And then if you just continue that additional 180 degrees, you rotate through the crista terminalis, the right atrial appendage, and then you're back to your home view. Again, very easy to achieve all of the relevant imaging for left atrial ablation with a simple transducer position. Ventricular imaging in contrast requires a little bit more finagling. So because we're imaging the ventricle, you want to place the imaging catheter into the ventricle. It's axiomatic. So in this case, what you want to do is you take the imaging probe and then you anterior flex. Some people find it helpful to put a lock on the catheter. You always want to be careful when you lock the ice catheter because it's a fairly stiff transducer. And so the lock really holds it into position. So you can inadvertently puncture things if you're not careful, but with complicated manipulations to be able to hold the catheter in position can be useful. But simply anterior flexing the catheter, drawing the tricuspid valve into the imaging transducer, and then advancing and you advance into the RV inflow tract, release the flexion, and then you clockwise rotate. And as you clockwise rotate, that imaging transducer will sweep through the septum and into the left ventricle, papillary muscle structures, and then if you turn, continue to turn, you'll look up at the outflow tracts. So this is a very easy, fluid motion. This is also a useful view in atrial imaging to look at ventricular function, to look at, to do screening for pericardial infusion periodically through the case to pick it up early, as we'll talk about later. So important view to learn how to obtain. There's a marriage between electroanatomical mapping and intracardiac echo. That marriage allows creation of three-dimensional geometries using the ice imaging. So what you see here on the left is a series of two-dimensional contours. Each of these green stippled contours is a two-dimensional contour that's obtained from the ice image. You can see here the active, this so-called fan. Here's the ice catheter, and here's what the ice catheter is seeing, and you can see that it is in line with one of these stippled images. And so you can essentially either in a manual way or a semi-automated way create these two-dimensional contours by tracing the endocardial geometry. And then as you sweep that image through, then you build successively more of these two-dimensional slices, and the system will interpolate a three-dimensional geometry. So I'm going to let this play, and you'll see the catheter sweeping. Now we're looking kind of up at the RV freewall and clockwise rotating, the imaging fan comes down along the freewall of the RV. As we get lower, we'll start to see the moderator band insertion on the freewall here, RV apex, septum, intraventricular septum here, LV, papillary muscles, and then we're back up, now we're looking up at the outflow tracks. So these types of images provide a rich context if you're doing focal ablation or focal mapping, can be obtained with a minimum of fluoroscopic use for the procedure, and are useful in that regard. Here's another example of imaging the outflow track, again, this is a whole hour sub-lecture, but basically now looking up at the outflow track, showing the position of the ice catheter and the fan, and as you track through, you're able to regenerate and visualize the relationship between the RV outflow tracks and LV outflow tracks, which are mutually perpendicular. So you see one in short axis, you see the other in long axis, but being able to lay out these anatomical relationships non-fluoroscopically is a real strength of intracardiac echo. For atrial ablation, this is when we're ablating around pulmonary veins, there are a number of complications that can occur. Characterizing pulmonary vein anatomy at the onset of the procedure is helpful to get a sense of your approach, whether it's a balloon-based approach or a catheter-based approach. Also, patients that have redo procedures, looking at Doppler characteristics, color Doppler and pulse Doppler, to get a sense of whether there might be areas of stenosis from previous ablation. Here's an example of a pulse Doppler signature pre-ablation and post-ablation in the same patient. You see a marked increase in systolic flow velocity from the pulmonary veins, and when you start to see levels that are over 100 centimeters per second, you worry long-term that this may result in some stenosis of the PVs. This is an example of, again, using the marriage of intracardiac echo and electroanatomical mapping to help guide ablation in the left atrium, specifically here, looking at the ridge between the left pulmonary veins and the left atrial appendage. In addition to, and this view here is kind of a cutaway view in the left atrial appendage here and the left pulmonary vein here, here's the ridge in between. Looking at this live echo view, you can see the projection of the ablation catheter is shown with a little green circle. As we sweep that catheter here on the vein side of the appendage and then here on the appendage side of the ridge, rather, you can localize that catheter in real time, obviously avoiding inadvertent complications, but also in a more precise way, defining where those more complex three-dimensional structures are to design your ablation strategy more effectively. There's a separate talk on transeptal catheterization, so I won't belabor it, but here are six different patients that are undergoing AF ablation with six different abnormalities of the intraatrial septum. PFO, ASD, lipoma, dyshypertrophy, patient with a double intraatrial septum, where you may want to target, you know, you'll want to go through that more complex region. This patient has an AMPLATS ASD closure device and we're tenting below, and then here a patient with a very thick mobile intraatrial septum that tends almost all the way over to the left pulmonary veins. So, using ice to guide your transeptal puncture, anticipate anatomical complexities of the fossa or the intraatrial septum, and facilitate the procedure and maximize safety. Throughout the talk, there'll be a few board-style questions that are interspersed. This is the first such question, so I'll just read the question and give you some time to consider the response. So, this is a 45-year-old woman who undergoes cryoablation for paroxysmal atrial fibrillation, and the lead-in is, which of the following is the best next step? Number one, advance the balloon distantly using the sheath. Number two, reposition the balloon approximately. Number three, initiate fronting nerve pacing. Four, increase the balloon inflation. Five, proceed with ablation. And you can see the echo clip here on the right, and I'll give you a few seconds to consider the response. So, we'll go on to the answer. Feel free to pause if you like. So, the correct answer here is to proceed with ablation. So, what the image requires you to know is where the balloon is located, and in this case, the balloon is located in the left inferior pulmonary vein. So, here we have the ice imaging catheter in the right atrium. We're imaging through the fossa valus. We're imaging through the in the left inferior pulmonary vein. So, here we have the ice imaging catheter in the right atrium. We're imaging through the fossa valus, and we see the left pulmonary veins in the far field. You also need to know what this red flow is, what it represents, and you notice it's broad laminar flow. So, this is flow from the left superior pulmonary vein. So, this is normal left superior pulmonary vein flow that is being displayed, not what you worry about with balloon position, which is the potential of a leak associated with the inferior pulmonary vein. And so, the correct answer here would be to proceed with ablation. The distractors advancing the balloon distally, inflating the balloon position are incorrect. The position of the balloon is really at its equatorial point in the left inferior pulmonary vein, so the balloon position is adequate. Initiating phrenic nerve pacing would be relevant for the right pulmonary veins, not the left pulmonary veins. Here, we're showing a fluoro image with the balloon catheter in the left inferior pulmonary vein. We're doing a contrast injection showing no reflux contrast around the balloon. The contrast, this is a balloon, slightly different balloon position, slightly more proximal. And now here you see a high velocity jet that is wrapping around the superior aspect of the balloon. Subsequent contrast injection here showing a leak on the superior aspect of the balloon. So contrasting these two images. Cabotricuspidismus ablation can be a very unforgiving procedure, largely related to the anatomical constraints of the CTI. So you can have ridges and deep pouches along the CTI. The gestation valve is often anatomically complex. And so how you being able to anticipate these types of anatomical limitations help you design your ablation strategy more effectively. And so when you have intracardiac echo, sometimes the echo can give you insight into these abnormalities. So here's an example of a patient with a very thick prominent gestation valve. You can see it extends up almost like an intracavitary structure, kind of similar to the valve that you see here and really helps to inform how you approach this with catheter positioning rather than trying to approach it directly. You loop the catheter back alongside in order to lay parallel to the tissue. Here's another patient. Again, using echo to manually contour the location of the CTI. And you can draw these in along that contour. So here we're showing, this is sort of an LAO caudal view. So we're looking up at the CTI. This is the IVC aspect. This is the tricuspid valve aspect. You can see kind of here in the septal plane with the projection of the hiss catheter more vertically. And so you look at this and you say, well, how am I going to design this line? Maybe this line would be the best because this is shortest in septal. But if you look in a different projection, now this is an RAO view. Now you see that the more septal aspects are complicated by this large pouch. And the lateral aspect, albeit longer, is much more flat. Here's how that looks on echo. So you can see here the septal view and the mid CTI view has this really deep pouch. In order to ablate this, you're really going to have to wedge the ablation catheter inside. And you always worry in that case that you're more likely to cause complications and get steam pops. And then you compare that here to the lateral aspect, which is more flat, which is the line that we ended up choosing for this particular patient. Ablating around the sinus node is increasingly commonly encountered in clinical practice. This is a patient that's undergoing sinus node modification where here we've mapped the location of the sinus breakout. In other patients, either focal atrial tachycardias or in the context of atrial fibrillation ablation where we're isolating the SPC, knowing the location of the sinus node is important. Also, parenthetically, the location of the sinus node and also parenthetically, the location of phrenic nerve, which is delineated here with the black dots where we capture phrenic nerve from the endocardium. The three-dimensional maps here make this plane look fairly flat and uninteresting. And if you look at ice, what it shows you in this region of the arcuate ridge, which is this ridge where you fall out of the SPC into the right atrium, is that it's a much more complicated three-dimensional structure. In many ways, it's really an intracavitary structure because it projects into the middle of the cavity. And it turns out that the vast majority of sinus node breakouts, certainly the autonomically-driven sinus breakouts, map to the arcuate ridge, this ridge here kind of at the SPC-RA junction. So being able to tag this on your electroanatomic maps is important, particularly if I'm doing an SPC isolation to know where this is and use that to design your level of ablation can be very helpful. For sinus node modification also, since this is often the target of ablation, looking at not only the edema that you get with ablation, which is shown here on this echo image, but the presence of epicardial edema, which suggests that you've ablated transneurally and affecting the epicardial aspect of the sinus node is correlated with the achievement of heart rate slowing and P wave modification in these patients. So ice can be a very useful adjunct with this procedure specifically. There is gathering momentum for the use of intracardiac echo in left atrial appendage occlusion cases. There has been a real steep increase in the number of left atrial appendage occlusion cases. They've doubled over the last 12 months. However, at this point, the vast majority of procedures are done with combination of general anesthesia and transesopageal echo. Over the last year, only about 6% of implants were ice guided. There are obviously inherent limitations in using anesthesia and TE workflow. Many centers don't have access to anesthesia. Often the anesthesiologist, if they're not cardiac anesthetist, may not be skilled in doing ice. And so you may need a third party involved, a general cardiologist or non-invasive cardiologist to do the imaging. You have to turn the probes over. So if you don't have a redundancy of probes, you may be limited by TE capacity. And some patients just frankly have contraindications to TE. Also, we're learning that even small leaks, leaks that historically we would not worry about are associated both with thromboembolic events and the potential for leak progression over time. So the fidelity of your imaging in the EP lab is critical because you wanna be able to see the appendage in multiple views so that you're not missing a leak. So if you only look in one view, you may miss a leak in a complementary view. As I've mentioned previously, one of the limitations of two-dimensional ice is that you have a single two-dimensional plane and that imaging plane is governed by the location of the catheter. Because the left atrial appendage is in the left atrium, the right atrial imaging planes are often inadequate to fully characterize it. So you have to move the catheter. So as opposed to TEE, which provides you omniplane function where you can have the TEE transducer in one location and you can vary the angle of your transducer from the vertical plane to the horizontal plane, you don't have that luxury with ice. You actually have to move the imaging transducer to get the view that you want. Here are a series of different field planes of view of the left atrial appendage. The top image here is the right atrial view. These are a series of 2D echo slices. And again, we're showing the position of the catheter here and the echo fan. So this is the perspective of the catheter looking at the left atrial appendage. In this case, in the relative far field, right atrial imaging plane through the fossa looking at the left atrial appendage. And you see, it's really a poor view. We're imaging at low transducer frequency in order to see it. And you really can't make much out in terms of the structure of the appendage here. Sometimes you get beautiful views from the right atrium, but it's a very inconsistent location. You can take the imaging transducer here and put it in the RV outflow tract. And now we're looking up at the appendage. So here we're looking through the aortic valve and seeing the left atrial appendage in the far field. Here, we've taken the ice catheter and placed it in the left atrium. And now we're imaging directly either from the pulmonary vein or directly from the appendage looking at a more on fossa view. And then here, lastly, we've taken the imaging transducer much like in the RV and placed it in the left ventricle. And now we're looking up at the left atrial appendage. So what I'm showing you here are these four different imaging planes. What you notice is, by and large, they're vertical imaging planes. They're like 90, almost all of them are 90s, direct 90s, or we're kind of looking up in a vertical plane from the RV or LV. So one of the limitations of standard RA and LA imaging planes for the appendages, it's very difficult to get a horizontal view as zero with ice. You just can't get the transducer to flatten in order to get that orthogonal view. One way to do it is the pulmonary artery. The pulmonary artery is a similar height to the left atrial appendage when you're in the main pulmonary artery. So in this way, you can get that fan flat and look at the ostium in a true zero, depending on the particular patient and the orientation of the outflow tract, how dilated it is. It's not an easy view to get, but it's probably the most reliable. But as you can see, in order to image the appendage, it's multiple views and sometimes views that are a little more technically challenging. There are a number of different three-dimensional, four-dimensional ice probes that are coming to market. This is an example of the Siemens probe, which is built on the Accuson catheter platform. So it would be familiar to many operators because the handle is identical to the Accuson catheter. It provides 2D imaging capabilities and 4D imaging capabilities. So a three-dimensional volume that changes over time and time is that fourth dimension. It also, like the 2D probe, provides pulse Doppler and continuous wave spectral Doppler and color Doppler in the 2D mode. Also, 4D color Doppler, which is nice if you're looking for leaks for a left atrial appendage occlusion device, has an adequate working length, 12 and a half French. Catheter design, the transducer design is different than the standard two-dimensional linear array. And the difference is that the transducer array is oriented in a helical fashion. So each transducer element is offset from the previous by about 10 degrees. And what that produces is a series of 90-degree sectors that are offset from each other. And the system will integrate these different two-dimensional slices into a three-dimensional volume. And that's what this looks like. This is this three-dimensional volume. And the volume has different dimensions. It has a height, it has a depth, and it has a width. It is not symmetric in the sense that the primary view is a 90-degree sector, which is shown here, this red arrow. The orthogonal view, which is a 90-degree offset, is only a 50-degree sector. So, and we'll show you some examples of how that looks, but it's not perfectly symmetrical. What you can do in these particular cases, and here's an example of how this looks in the sort of XYZ plane, where you have a right-to-left view, your front-to-back orthogonal view, which again is a 50-degree view, so it's narrower than your 90. And then the mutually perpendicular sort of cross-sectional view, which can be adjusted. So, for left atrial appendage imaging, you start with your basic view of the left atrial appendage. This is obtained with the imaging catheter in the left atrium, looking directly at it, so kind of like your TEE90 view. And then you enter the NPR mode, the reconstruction mode. And the reconstruction mode gives you that initial 90. You do notice, by the way, some degradation in image quality when you go from 2D to 4D. Your 90-degree view here, and then your orthogonal zero-degree view, which is the side view. So, this is your 90, and this is your zero. And what you'll see is, when we do the reconstruction, what we're going to do, as I let this play, is you're going to adjust your area of interest. So, we're looking at the landing zone where we want to land the device. We're adjusting it in the 90, and then we turn and adjust it in the zero, where we anticipate the location to be. And that gives you a cross-sectional view here in the blue box. That cross-sectional view can then be contoured manually. You can see here multiple different measurements showing the oval structure at the location of the landing zone. You can also contour the perimeter as well. And this is very useful in making a decision about device sizing. Here's an example of imaging the device once it's deployed. So, you can see here a 2D, 4D image, and then color doppler here in multiple views, showing no leak around the device. It's also nice because you can sort of see the device when you do your tug test and kind of see the device in multiple planes. So, it's a very rich anatomical context. And for certain patients in certain centers, this might be a suitable alternative to using transesophageal echo for these procedures. Second ward-style question, we're going to shift to ventricular ablation. 72-year-old man undergoes ablation of idiopathic PBCs. Data is shown from the earliest RV mapping site. Which of the following is the most likely site of successful ablation? So, responses are RV outflow tract, pulmonic cusp, right coronary cusp, left coronary cusp, parahysium region. We have the clinical PBC and corresponding pace map here at the site, where the catheter is oriented in the RV. You can see the electroanatomic activation map, and you see the local electrogram. And I'll give you a few seconds to consider. So, the correct response here is the right coronary cusp. And when you integrate the data that you have, first of all, you have a left bundle V4 transition PBC with a left inferior frontal plane axis. So, this is a typical outflow tract morphology. Here, you have the position of the ablation catheter oriented inferior to the pulmonary valve plane with a broad early area of activation. The timing down at the hiss, which is one of our distractors, is late. And so, obviously, option number five is eliminated. And so, really, it's a question of saying, we have a suboptimal pace map that doesn't fully replicate the clinical PBC. You have a broad area of early activation. You have an electrogram, local electrogram, which is sharp and presystolic, but has a unipolar, corresponding unipolar with a little initial R wave and less steep dvdt. And so, this is all pointing you to say, we're close to the area of interest, but not quite there. So, you need to know what is close spatially to this particular region. And the answer is the right coronary cusp. And intracardiac echo is very helpful in demonstrating these types of anatomical relationships. Here is the same patient, same map, now with a activation point in the right coronary cusp. You see the geographical proximity of these two structures. You see the local electrogram that we get in the right cusp, much earlier presystolic. You can see on the echo image here, earliest right coronary cusp activation, earliest RV alpha tract activation in blue, and you see the proximity. So, this area in between is ventricular myocardium. So, these arrhythmias often originate from the superior portion of the interventricular septum, and we can get at them from multiple different areas. Sometimes one is more favorable or closer to the actual site of origin, as in this case, the right coronary cusp. Outflow tract ablations, there are different orientations to view the outflow tract. When we look at this particular view, which is obtained again from the RV inflow tract looking up, here you see the RVOT, the pulmonary valve, left pulmonic cusp, aortic root, looks very much like an anatomical specimen. So, you see here the interposed muscle in between and connecting the aortic root and the pulmonary valve apparatus, and this is the common area, the alveosteum, common area of origin for ventricular arrhythmias. And so these particular regions, the region in between the right cusp and the rv alpha tract and the region in between the left pulmonic cusp and the junction of the right and left coronary cusps are areas to, you know, to always consider in these types of patients to map in between, which is more proximate to the site of origin. This view, which is a right atrial view now, we're seeing the aortic root to the level of the sinus tubular junction and long axis and almost a short axis view of the pulmonary artery is the complementary view. So positioning catheters, in this case with the ablation catheter, prolapsed through the aortic valve and dragged back to the commissure. Here's a patient where we mapped again that area in between the left pulmonic cusp, which again is the position of the ablation catheter here, which is prolapsed, almost retrograde approach, where we go through the pulmonic valve, bend the catheter and pull it back against the pulmonic valve plane. And the proximity between this location and the complementary location at the junction of the right and left coronary cusps, you can see the electrograms for this clinical PBC, which are almost mirror images of each other and very similar activation times. Obviously, the characteristics of the bipolar and unipolar electrograms are more favorable on the LV map here on the bottom with the catheter kind of wedged in between the commissure. But ECHO highlighting the proximity of adjacent structures and facilitating your mapping technique. Sometimes ECHO can give you important insights into why procedures fail. So this is a case of ablation in the RV outflow tract and kind of at the level and above the level of the pulmonic valve. You can see here multiple lesions given, you can see the position of the ablation catheter, which is also in this case placed through the pulmonic valve and then looped back and pulled down against the valve plane from the superior aspect. You see the type of electrogram, sharp electrograms, which are characteristic of the PA type electrograms that you get in this area. You get good force. But when you look at ECHO, what you see is the catheter tip itself, which is highlighted here in green, is not against muscle. It's against the valve. So you can get far field electrograms, even when you're not in contact with myocardium and you get contact force, but you're nowhere near where you need to be. So ECHO can be very useful in guiding positioning of the catheter to avoid unintended complications in this area. Papillary muscle ablation is greatly enriched with the use of intracardiac ECHO. When you look at this type of anatomical specimen of the left ventricle, which is a sort of a lateral view with the mitral valve apparatus intact, and you can see the chordae of the posterior and anterior papillary muscle. And you look at the complexity of the papillary muscle structures, the trabeculations that connect the dominant papillary muscles. And you consider that ventricular arrhythmias could really originate inside any of these little strands, which often contain Purkinje material. It's really a wonder that we're successful in these ablations at all. But using, leveraging the imaging to facilitate the procedure can be very helpful. And as you see in this image here, again, this is an image which is a reversed image just to kind of line up the imaging planes to make them complementary with the anatomical specimen. You can really highlight very easily the structure of the dominant papillary muscles. In this case, they can be contoured independent of the endocardial geometry and really gives you a platform on which to perform your detailed mapping procedure. Similar, in similar fashion for the right ventricle here, anatomical specimen showing the supraventricular crest, the parietal and septal bands, moderator bands, septal papillary muscle structures. Almost as complex as you get in the left ventricle, arrhythmias can arise from any of these structures. So using the ICE image to highlight and manually contour regions of interest, as well as using it to verify that the catheter is opposed to the tissue of interest in real time is of paramount importance in these particular procedures. Here's an example of ablation of a posterior papillary muscle PVC from the left ventricle. And here we're showing the echophans sweeping through the posteromedial pap muscle, wire diagram of the endocardial contour separating it, type of electrogram that we get here on the the lateral aspect, the more septal aspect, and here the more infralateral aspect. So really using discrete data points and treating the area, the geometry of interest as a separate three dimensional structure can help facilitate mapping these complex structures. Next board style question, 58 year old woman with hypertrophic cardiomyopathy undergoes VT ablation. Which of the following findings is most likely? Number one, normal bipolar and unipolar voltages. Number two, focal VT mechanism. Number three, basal septal bipolar low voltage. Number four, need for epicardial mapping. Number five, dynamic LV outflow track gradient. I'll give you a few seconds to consider. So the correct answer here is need for epicardial mapping. And what we're highlighting with the echo image is the nature of the hypertrophic cardiomyopathy. So what you notice is that the thick region and the area of obstruction is really mid-cavitary. It's not your traditional basal septal HOCUM phenotype where you're likely to get outflow track gradients and septal scar. This is the type of HOCUM phenotype which produces apical aneurysms and apical dysfunction. As you can see here, you see hypokinesis, akinesis of the LV apex. What we're highlighting here is echo intensity. And that echo intensity is non-endocardial. So this is the endocardial aspect here at the infra apex. And this area of echo intensity, which essentially what that means is you have a large confluent region that differs in its echo texture with the surrounding myocardium has increased density. And that's what you see with scar tissue. So you have non-endocardial scar in this particular area, presence of an apical aneurysm. So these types of patients of HOCUM patients tend to have reentrant VTs that involve the apex. They tend to have large areas of bipolar, voltage attenuation, multiple VT morphologies, often require the combination of endocardial and epicardial mapping in order to eliminate their arrhythmia. May need repeat procedures, but are substantively different than your typical patient with basal outflow track obstruction and dynamic outflow track gradients. Other types of cardiomyopathy patients, particularly non ischemic cardiomyopathy patients, have a predilection for intramural substrate, and that intramural substrate can be very challenging from a therapeutic perspective. So being able to define that in a, in a real easy online manner in the EP lab can be very helpful. This is a patient, again, that has, you know, fairly normal LV function. Has fairly normal, completely normal signal characteristics on the endocardium and epicardium, but has an area of echo intensity in the mid wall that corresponds to a large area of unipolar voltage attenuation along the lateral wall. And so knowing where this area is can help guide your ablation approach, be it from the endo or be it from the epi, in order to eliminate these patients' tachycardias. Next question, a 64-year-old man undergoes a fibroblation, during which there is an acute decrease in blood pressure to 70 or 40. Which of the following is the best next intervention? Option number one is LASIX 20 milligrams, two, phenylephrine 100 micrograms, three, pericardiosynthesis, four, percutaneous LVAD, five, stat surgical consultation. So the important part of this particular case is recognizing the mechanism of hypotension. And in this particular case, we have dynamic LV alveolar tract obstruction. So you can see systolic anterior motion of the mitral leaflet and obstruction of systolic flow through the LV alveolar tract. There is a clear space, a pericardial clear space here, which is much more prominent in systole, is less prominent in diastole, is close to where the left atrial appendage sits. This is a common clear space that you see, which is augmented by volume contraction and dynamic LV function. For pericardial effusions, they tend to be circumferential. They tend to be, you know, you would not just see it here, you would tend to see with this magnitude, you should see it in other areas, see it more around the apex. So this is LV alveolar tract obstruction, which is treated with fluids or afterload increase with phenylephrine to increase pressure and increase cavity size. The other options would be incorrect. For the reasons stated. Characterizing mechanism of hypotension, whether it's an atrial ablation or ventricular ablation, is one of the most powerful benefits of using real-time echo imaging. These things can happen very quickly and being able to know what the mechanism is so that your first intervention is the appropriate intervention is very empowering, because treating one patient with a certain intervention, one of these four patients with LASIKs may be the appropriate intervention for other patients, may facilitate their hypotension and make the patient worse. So you want your first intervention to be an informed intervention, an appropriate intervention to mitigate harm, and echo can really provide you almost immediate feedback and insight into what that mechanism is. Management of thrombus. In this case, this is an example of using ice to prevent a complication. So this is a patient that's undergoing transeptal puncture and here is your transeptal apparatus. And here is the large mobile thrombus that's present on the sheath, on the transeptal sheath. Often these occur, not at the tip of the sheath, but at the intersection between the sheath and dilator. It can be quite large. In this particular patient, they were on triple anticoagulation in addition to heparin with an ACT over 300. So the formation of these clots can sometimes be a little idiosyncratic. And so being able to see this before you translocate it to the left atrium is very very powerful. And in this case, you wire it, pull the sheath out, clear the thrombus, and then proceed with the procedure. Catheter-associated clots. Here's an example of a circular mapping catheter and a mobile thrombus are managed differently, usually by trapping the thrombus and then pulling it back to the right atrium. Tissue-associated clots, like in this particular case, where we're ablating around the right pulmonary veins and you get a little piece of thrombus here, are best treated with avoidance and continuation of anticoagulation so we don't disrupt it mechanically. So each of these is managed a little bit differently, but it's the recognition that's the important part, and thereby recognizing it can be managed more effectively and you can prevent the downstream consequence. Management of pericardial effusion, as we've mentioned. Seeing it early and doing screening assessments, and I try to do this when I do a fib ablation, when we're checking an ACT, I just take a quick look with the catheter in the left ventricle, in the right ventricle rather, looking for small areas of fluid, and you start to see early areas of separation between the pericardial layers. Sometimes it's merely due to ablation. In this particular case, this is just a patient that had very extensive ablation along the posterior wall, and you start to see epicardial edema, and that epicardial edema separates the endocardial layer and the tissues around the esophagus. In this particular case, on the bottom left here, you start to see a clear space that develops between the visceral and parietal pericardium. So this is an early effusion that was picked up, and again, you pick it up and you can reverse anticoagulation, and in some cases avoid having to tap the patient. In this particular patient, this is a more dramatic patient that was undergoing structural heart PT ablation with RV ablation, and here you see a large intramural hematoma that's contained within the inferior margin of the right ventricle and associated pericardial effusion. This is a patient where you want to get control early on in case this area might rupture. You might involve cardiac surgery on the sooner end in the event that the patient ends up having a free wall rupture and needing to go to the operating room. So cluing you into the presence of a complication and the severity of the complication so you can plan more effectively. And then here, another patient that's getting pericardial access and has developed a pretty large area of thrombus within the pericardial space between the pericardial sac. You can see here a guide wire on this bottom right view. The guide wire is in the pericardial space, but it's surrounded by thrombus. So this is a surgical emergency, a patient that needs to go to the operating room. So recognizing this is paramount importance because really the clock is ticking. So in summary, ICE is a very versatile, I would say the most versatile imaging platform that we have in electrophysiology. It can demonstrate the anatomy very clearly and also variance in anatomy is useful in pulmonary vein ablation, ablation of intracavitary structures, and has an emerging role in left atrial appendage occlusion cases. The catheter positioning is of critical importance for intracavitary structures, moderator band, papillary muscles. Characterization of arrhythmia substrate, particularly in your patients that have intramural substrate where we're trying to make sense of the signal characteristics that we get with our electroanatomical mapping and using that to manually contour and target regions that are less accessible to catheter mapping. And lastly, being able to detect early and even in some cases prevent procedure complications with the ICE imaging is very empowering for the operator. That's all I have. I thank you for your attention and best of luck in your studies.

intracardiac ultrasound

ICE

electrophysiology

imaging concepts

catheter design

atrial ablation

ventricular ablation

electroanatomical mapping data

patient safety