From Transesophageal Echocardiography to 4-Dimensional Intracardiac Echocardiography: Redefining Imaging in Structural Heart Disease

Podcast Discussion With Nassir Marrouche, MD, and Karim Al-Azizi, MD

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EP LAB DIGEST. 2025;25(12):Online Only.

Interview by Jodie Elrod

This podcast includes a demonstration of the use of a medical device.  The steps demonstrated with respect to the use of any medical device in this presentation may not be the complete steps of the procedure. Individual physician preference and experience, as well as patient needs, may dictate variation in procedure steps. Before using any medical device, review all the Instructions For Use with particular attention to the indications, contraindications, warnings and precautions.

Nassir Marrouche, MD and Karim Al-Azizi, MD are compensated by and presenting on behalf of Biosense Webster, Inc., and must present information in accordance with applicable regulatory requirements.

In this episode of The EP Edit podcast, 2 leading voices in electrophysiology (EP) and interventional cardiology (IC) discuss the future of imaging ownership, the impact of pivotal trials like OPTION and CHAMPION, and how technologies such as NUVISION NAV^™ Ultrasound Catheter (Johnson & Johnson MedTech) 4-dimensional (4D) intracardiac echocardiography (ICE) are reshaping operator confidence, procedural efficiency, and clinical outcomes for structural heart procedures like left atrial appendage occlusion (LAAO) and tricuspid valve interventions. 

Can each of you start with a brief introduction about yourself?

Nassir Marrouche, MD: My name is Nassir Marrouche. I am the director of the Heart and Vascular Institute at Tulane University and director of the EP program as well. Happy to be here.

Karim Al-Azizi, MD: I am Karim Al-Azizi. I am an interventional cardiologist and structural heart disease specialist at Baylor Scott & White The Heart Hospital - Plano. I am the medical director for the cath lab and program director for the structural heart disease fellowship. Happy to be here.

While ICE adoption has continued to expand, LAAO still heavily leans on transesophageal echocardiography (TEE). What will it take for EPs and ICs to fully own LAAO imaging, and how do you see trials like OPTION impacting that shift?

Nassir Marrouche, MD: Let me start with that question. In the last 12 years, most of us in the US and Europe have been very involved in LAAO procedures, specifically with the Watchman (Boston Scientific) and other devices. Moving to exclusively ICE-based procedures in our practice has been a major shift for the better. Our volume has increased threefold—and in some cases fivefold—compared with when we were using TEE only. That was helped with the OPTION trial data, but let's focus on TEE versus ICE. As an electrophysiologist, to schedule procedures in my clinic, I need an imaging specialist to be available to perform TEEs in the EP lab. Depending on how fast you are and how complicated the case is, the procedure can take up to an hour or be only 15 minutes. We moved completely to ICE last December / early January, so we are now a completely ICE-based hospital and university using ICE to implant LAAO devices.

Finally, it feels like we are free. Every time I used to schedule a procedure, it was a big hassle just putting it together. For the first month, there was an initial learning curve, but it has now become the standard of care for us and there is no going back. I believe this adoption will hopefully begin taking place everywhere else and that our colleagues will start using it on a routine basis as well once the data start coming out. My partner on the podcast today, Karim, will be sharing his experience as well. Once EPs start recognizing its success and how easy the flow is—particularly during ablation procedures—TEE is unlikely to have a continued role in their practice for these cases. 

Karim Al-Azizi, MD: I share the same sentiments about the idea of using ICE. Our journey with ICE guidance and LAAO started a couple of years ago and with the launch of 3D and 4D ICE. It is not new to us in the structural heart space. We have used it for patent foramen ovale (PFO) and atrial septal defect (ASD) cases, just like our EP colleagues use it for transseptals and guiding ablations. Using ICE, at least from the structural side or IC perspective, gives us freedom. What we used to rely on—an imager, an anesthesiologist to set up the room, an anesthesia technologist to bring in the case and the cart—we no longer need to rely on any of that. We no longer need to intubate the patient or take the patient to the post anesthesia care unit (PACU).

We have emerged and have essentially evolved to a minimalist LAAO program, although we are not yet 100% because we have a variety of implanters. We perform over 400 appendages a year between our structural ICs and EPs. From a cath lab perspective, what I care about most is quality and volume. We do not have specific LAAO days, so it is just another case or add-on that we would put on the list. If it is truly a moderate sedation ICE-guided LAAO case, all I need in the room—in addition to my Lean team in the cath lab—is an echo tech and echo machine, and I can complete the procedure. Depending on the complexity of the case, for an ICE-guided LAAO and crossing into the LA, the shortest time that we have recorded so far is anywhere between 20 to 25 minutes.

It has definitely given us the freedom to essentially not rely on other services and perhaps reserve specialists for other critical needs in the hospital—for example, anesthesiologists for other major procedures and imagers for complex structural interventions, whether in the operating room (OR) and other settings.* So, it gives us flexibility. In addition, with the growth of cases in our facility, we have increased our time to doing elective scheduled cases beyond additional working hours. That means that what used to be only a left heart cath or percutaneous coronary intervention (PCI) that can be done at 6 PM or 7:00 PM, I can actually add an ICE-guided LAAO since the patient will be spending the night; especially if it is that late, we would do that and keep the patient overnight and they would still go home the next day. So, it has definitely widened the scope of how to treat those patients beyond the traditional times that we have always done. The biggest obstacle that remains for us is the cost of the catheter, which I expect will hopefully decline over time as efficiency improves, treatment volume increases, and advances in technology enhance its potential for reusability.

Nassir Marrouche, MD: I agree. The cost is an issue, but if you think about the efficiency and take it all over a period of time, you are really saving money, because you are adding procedures and shortening your lab time by a significant amount. As you know, Karim, this has a major impact on the hospital system. But as you said, and it is a very important point, you can now add a Watchman case without having to call 6 or 7 people to be available, such as the echo tech, imaging specialist, etc. Those times are over. 

The future is happening now. Since OPTION, the majority of my cases are now concomitant LAA closure plus ablation procedures. But for Karim, this perspective reflects ICs who have the option for TEE, since they do not perform atrial fibrillation (AF) ablations and can continue to use ICE as a primary imaging modality. So, that speaks volumes, highlighting the ease of integration and the efficiency and ability to perform procedures at any time with speed. By the way, do not underestimate the added invasiveness of placing an esophageal probe, whereas with this approach—already within the atrium—only an additional catheter is required. Taken together, this represents the future and hopefully more than 70% to 80% of labs will be adopting it.

Concomitant cases are rising—are we at a tipping point where EPs will take over more structural procedures such as LAAO, or will ICs continue to hold ground given the anticipated volume? How might CHAMPION trial results influence that balance? 

Karim Al-Azizi, MD: Yes, happy to. In a concomitant procedure, where EPs can ablate and implant, it is a huge plus. It becomes more of a step for ICs, who really should appropriately think about ablation first before we start putting in devices. But nonetheless, volume and demand for LAA closure have been increasing and will continue to increase significantly. Right now, there is direct-to-consumer advertisements for both the Watchman and Amulet (Abbott) devices. 

So, we have the CHAMPION-AF study, which is looking at LAA closure in patients who are not high bleeding risk outside the current indication for nonvalvular AF, and we have the CATALYST study, which is also enrolling for the Amulet device for the same indication.

If the data shows it is superior to anticoagulation or as good as anticoagulation, preventing stroke minus the bleeding risk, the community is in trouble, because the demand for these devices will exceed the current levels of what we can do. If we are already saying that we can achieve this much, we are trying to think about ICE and moderate sedation and expanding procedural hours, we very quickly will be seeing people who perhaps were not structurally trained, such as ICs who maybe did not spend time in structural heart training. We know the NCD requires 25 transseptals over a 2-year period. This is eventually attainable in many interventional fellowships. Obviously, this is in the realm of EPs, so there will be a very high demand on their end, but there will also be an increase in demand everywhere beyond the capacity of what we have right now.

Nassir Marrouche, MD: I agree with Karim as well in terms of ICs still having a stake in implanting devices. However, the patients that we deal with are AF patients and this usually starts with the EPs. As you know, Karim, the guidelines have recently been changing to ablation as first-line therapy more and more in different patient populations. We started with heart failure, but patients now have the option to undergo ablation as a first-line therapy. Since we are ablating these patients, we are able to put in these devices. In my opinion, the OPTION trial, led by Dr Oussama Wazni and colleagues at the Cleveland Clinic, has had a major impact on the field. For those of us who have been treating this disease for decades, the number one challenge we have dealt with is how to manage our patients on warfarin. Remember that drug? This was followed by the subsequent bleeding risks with NOACs and so on. To have that elevated risk taken away, it is a big deal, let alone the cardiologists and ICs who manage these patients. So, I believe that, as EPs, we will increasingly see patients, perform ablation, implant a device in most cases, and discontinue drug therapy—establishing this as the emerging trend. A smaller subset of patients who have already undergone, or do not require, AF ablation may instead be managed by ICs or structural heart specialists, if they have capacity alongside procedures such as valve repair and TAVR.

But specifically after OPTION, we have seen the integration more and more in EP procedures. It used to be 50/50 but is shifting now to almost 60/40 for that reason. There has been a CPT code for this since October 1st to support these combined procedures, so that has helped the adoption. 

I also want to mention the reason why this became standard of care for us. Using NUVISION NAV^™ Ultrasound Catheter for this procedure has changed the way I do things. I can look at the device from 2 different views in 4D, which is a major help for improving adoption for me, as I do not think I would be as fast. I tried a couple of cases with regular ICE and was not as satisfied. So, that has helped to shift as well. Karim, I am curious about your experience. Did you do 2D ICE versus before you started?

Karim Al-Azizi, MD: I do not think that 2D ICE is capable of completely assessing the device and assessing for peri-device leak. Our promise to these patients is that this is intended as a “seat belt” against strokes and if we are going to put in a device that enables them to stop anticoagulation, whether at the time of or even days later, we really need to make sure that we do not leave any leaks behind, because even though the IFU for some of the devices is up to 5 millimeters, we know that less than that has been linked towards worse outcomes and stroke events. So, I do think that the ability to do multiplanar reconstructions or multiplanar imaging, where you are able to digitally steer from a single location or perhaps 2 locations of the ICE catheter within the LA, has basically revolutionized the whole aspect of being able to assess the appendage and the leaks around the device, to ensure not only that the device is stable, but that there are no leaks around the device.

Going back to the idea of closure and ablation, I shared the same thing with you. I think rhythm treatment first is very important for those patients and to follow with the device. But from the perspective of an IC, now that we are seeing the growth of pulsed field ablation (PFA) and how rapidly AF ablations are happening as well as the ease of the procedure, I think more and more we will be seeing patients, if they are not treated at the time of the ablation, they may have been ablated and they may be staged later on for a LAA, especially if they did not meet the current indication for coming off anticoagulation. So, it will be very interesting to see in the next few months to years how clinical practice changes. In my opinion, it is an EP procedure unless ICs start to do AF ablation, since PFA looks very easy. But other than that, I think it is an EP procedure until proven otherwise.

For tricuspid procedures, use of ICE is expected in 65%-100% of cases. What is your take on the limitations of TEE in these procedures, and how do you see 4D ICE, like NUVISION NAV^™ Ultrasound Catheter , changing that landscape?

Karim Al-Azizi, MD: Yes, thank you for this question. This is an important question, especially in the tricuspid space. We have been part of the tricuspid clinical trials since the beginning of early feasibility and now the pivotal and commercialization, and there are more devices that are coming into play that come in forms of whether it is edge-to-edge repair, a replacement, or even in the form of annuloplasty or some sort of structural repair to that area in order to reduce the burden of tricuspid regurgitation. What we know is that from the therapy that we have, the best you can get is reduction in heart failure hospitalization, as seen by the 2-year data of TriClip (Abbott) as well as improvement in quality of life as seen by both the transcatheter replacement therapy with the EVOQUE Valve (Edwards Lifesciences) and the TriClip.

It is the same—I treat or look at it as an LAAO. First and foremost, the goal is to ensure a safe procedure^#—one that improves quality of life, even though a mortality benefit has not yet been demonstrated. So, when we talk about this, especially in the tricuspid space, the imagers are typically moving the TEE constantly from a mid-esophageal view to a transgastric view to improve the imaging quality and be able to acquire the images that they need, which we know can be linked to esophageal injuries. As Nassir highlighted, a TEE is a TEE, but a TEE can sometimes not be benign, especially in patients with tricuspid regurgitation who may have hepatic congestion or congestive hepatopathy and may have some degree of variability of their esophagus.

So, going back and forth may cause some degree of an issue. This has been seen and published. There was a recent JACC publication as well as a few years ago highlighting the degree of potential esophageal injuries just with TEE manipulation. But what we have also learned from the clinical trials is that while TEE is important, TEE alone is not enough. So, the way we have addressed this and adopted the ICE algorithm and part of the TEE algorithm is performing tricuspid transcatheter edge-to-edge repair (TEER) procedures, which in my opinion, are the toughest to date, because you are at the mercy of the image that you are trying to get. As we know, the tricuspid valve is an anterior structure. You are having to image from the esophagus all the way forward. If you have a mechanical mitral valve, you are definitely shadowing over the septal leaflet.

If you have a lead, you may be shadowing as well. Or, the device or guiding catheter itself may be shadowing over as well and you are not able to see. So, to address this, we have applied a hybrid algorithm where the TEE sits in the stomach to give us an idea of the orientation of the device looking at the anatomy of the tricuspid valve, and then the ICE is partly in the right atrium looking over the tricuspid valve to give us an idea of where the device is sitting in relation to the leaflets and what we would consider getting ready to capture the leaflets. So, between that and switching back and forth using the same console, I think has improved our efficiency in treating patients for tricuspid valve regurgitation. But actually, in my mind, and I think this is just anecdotal evidence, because it has not been published yet, you are more likely to see the regurgitation and be able to act on it, as opposed to if you do not see it, you do not know it and hence you do not treat it.

So, by the time you follow up on these patients, they may not have had significant improvement in the regurgitation, because we may have missed the regurgitation at the time of the procedure. Therefore, I do think it improves efficiency when you deploy it in a way where it is truly an algorithm and it is deployed from the beginning of the procedure, and not when a team is in trouble or 2 hours into the procedure. We have seen changes in our procedure from 3 and 4 hours down to 45 minutes. Also, I think it is probably better for patients once we get more data and get more comfortable with navigating the ICE catheter and applying the idea of what we call 3D navigation to deploy tricuspid TEER devices. It tends to be easier with replacement devices, as they are more likely to conform to the annulus depending on which device we are talking about, especially investigational devices.

Finally, annuloplasty devices that are still in clinical trials—for example, the Cardioband (Edwards Lifesciences)—use multiple anchors deployed under ultrasound guidance, either with TEE and/or ICE, to encircle the annulus and mimic a surgical annuloplasty, followed by cinching. There are times during the procedure when there are blind spots where perhaps ICE has become very useful in shedding light on that area. So, I think the purpose and the use of ICE in tricuspid interventions is key. However, it is on the community, industry, and societies to actually implement these educational areas to ensure that all heart teams are now being approached to use these commercially available devices and are able to understand and use 3D or 4D ICE at the time of treating their patients.

Dr Marrouche, your thoughts?

Nassir Marrouche, MD: I really believe the tricuspid clip procedure will not be possible without 4D ICE^# as an established procedure. It will instead be considered a boutique procedure because of the issues that Karim was mentioning. There is no way to establish this with all the things that he mentioned. I do not do them, but I am aware of the anatomy of the tricuspid annulus since we ablate it and they fix it. We perform ablations for cavotricuspid isthmus (CTI) lines and implant pacemaker leads, but insufficiency of the tricuspid annulus has become a clinical concern. There is a large number of patients who need to be treated, but without the availability of 4D ICE or at least ICE in general, this would be almost impossible for massive adoption, in my opinion. 

How has NUVISION NAV^™ Ultrasound Catheter changed your approach to LAAO or tricuspid procedures—in terms of procedural efficiency, operator confidence, or clinical outcomes?

Nassir Marrouche, MD: The capability of the 4D ICE catheter with multidimensional imaging has helped a lot. I think my team and other EPs share these same thoughts and experience. With standard positioning of the catheter, one in the left superior pulmonary vein and one in the mitral valve, you are done. By the way, placement of the procedure is becoming more and more ICE-guided step by step. I do not use any dye or angiograms to assess or locate positioning pre and post procedure, which is a major advantage. I have not used it in the last 8 months since adopting this approach with ICE.

In my opinion, EPs are discussing this widely—at every meeting, our colleagues concur that it has become the standard of care in clinical practice. People are slowly but surely adopting this into their practice. I anticipate that by end of the year, perhaps sooner, every EP performing ablation will be using ICE; and when implanting a Watchman device, they will routinely wait for the imager to perform a TEE and take advantage of that catheter. Johnson & Johnson MedTech is integrating this into the mapping system. It is not there yet, but hopefully soon—we were promised it would happen this year. It will be a major advantage to have it all in one, as it has been very helpful for the whole procedure.

Karim Al-Azizi, MD: Yes, I believe one of the things that people do not realize about the NUVISION NAV^™ Ultrasound ICE catheter, which is compatible with the GE system, is that it connects to a platform that allows integration with CT and the potential fusion of ICE and CT images, which is an important advantage that we can continue to build on. Just thinking about how you can fuse different imaging modalities is key. From a structural IC perspective, one thing I want to highlight is the importance of the cardiovascular or interventional structural imager. Tricuspid cases tend to be lengthy, resulting in substantial radiation exposure for physicians. Reducing procedure time decreases radiation exposure, lessens fatigue, and lowers the risk of injury. 

Whereas ICE was once thought to replace the imager, the opposite has proven true—it fosters a common language and shared visualization, allowing us to apply consistent imaging principles and ultimately treat more patients. So, from a tricuspid space, we are still learning, but I feel that the momentum is there to propel the use of ICE, because it is truly enabling. ICE can be considered as an enabler for these therapies and may potentially improve outcomes, although supporting evidence is not yet available. 

I also want to address the safety of these procedures and about LAAO specifically. From my perspective, when I speak with a patient, I describe this as a seat belt. This is a preventive therapy, so it needs to be a safe procedure. This is not a chronic total occlusion PCI, transcatheter aortic valve implantation (TAVI), severe mitral regurgitation, mitral TEER, or mitral edge-to-edge repair.

So, how can this be safe? There have been questions about the sole use of ICE and LAA closure, and multiple papers that have retrospectively looked at the use of ICE and LAAO guidance. There is substantial evidence of both efficacy and safety, demonstrating that it is safe to use, with a modest initial learning curve. A recent study, based on a larger registry, suggested caution and indicated a wait-and-see approach. 

Our program was highly interested in this and is conducting the first prospective, randomized trial comparing ICE guidance with TEE guidance in all LAA closures. We aim to assess not only the procedural safety at the time of intervention, but also the detection of residual leaks at 45 days, including patient-reported outcomes.

Patients were given anesthesia questionnaires to evaluate their experiences, including whether the procedure was uncomfortable, how they felt during and after the procedure, and their perception of resource use. This is particularly relevant because ICE is not reimbursed in LAAO cases, despite offering advantages that extend beyond current practice. 

I do think that operator confidence and efficiencies increase. Anecdotally, I believe that clinical outcomes improve once the learning curve is overcome, particularly in tricuspid therapy and when imaging poses challenges. However, additional data are needed to demonstrate these findings more broadly and support potential reimbursement efforts.

Finally, how do you see ICE evolving your practice in the next 1 to 2 years, and what shifts do you expect in physician ownership, collaboration, or preference for ICE over TEE?

Nassir Marrouche, MD: The majority of EPs in the US already use ICE in their practice. This came to me when we were talking about cost. It is standard of care in AF ablation procedures in the US. I think more than 90% of EPs now use ICE. OPTION demonstrated that in patients undergoing ablation, we can safely and efficiently implant a Watchman device. This procedure is increasingly becoming routine, as patients elect this pathway to avoid repeat interventions, discontinue blood thinners, or address bleeding complications. We also now have a CPT reimbursement code to back this up. Therefore, use of a 4D catheter is an obvious choice for procedures that combine ablation with closure device implantation.

From the EP perspective, I believe that the use of ICE in the EP lab will hopefully be happening within the year. It will be the standard of care, because most patients will have access to 4D integration. 

Having said that, there is something else we should mention. With NUVISION NAV^™ Ultrasound Catheter, improvements in lesion prediction are notable; when assessing lesion durability during ablation, which is very important, PFA is very fast. Are we sure that the lesion is forming? Is it good enough to move on to the next spot? The NUVISION NAV^™ Ultrasound Catheter will have some algorithms to help us differentiate the size^#.

This is happening soon—it is in research and may be in action next year. So, it is beyond just placement of the closure device. We have talked already about the structural changes, including change in the atrium, volume, flows, and assessment of the valve during a procedure—and having the freedom to move with ICE. We have not talked about these advantages because we are already impressed with TEE. The other stuff is coming to make us dependent, especially with lesion formation and structural changes during and after ablation. It will be visible on the mapping system—integration with the 3D mapping system in EP. So, I cannot see us not adopting this as standard of care in every procedure going forward, especially when these additional features become available, let alone the need for closure device placement in almost the majority of EP procedures so far.

Karim Al-Azizi, MD: I completely agree. With the nature of adoption, I think EPs have lived with ICE since their training days and continue to do so with 2D ICE and now 4D ICE. But the reality is that because of the cost of the catheters and the current inability of reusing or repurposing them for a second use, it has become an obstacle to adopt this nationwide and in many programs. When we meet with our EP and IC colleagues at society meetings, this seems to be the general consensus. The proposed number that people are using ICE as their only imaging modality in a LAA closure is somewhere between 20% to 25%. 

These are numbers that will continue to change, but I think there are a couple of things that we need to highlight. The first is highlighting the potential advantages of a minimalist LAAO procedure. It is advantageous to the program and patient. Actually, many patients have now been requesting not to go under general anesthesia or TEE for whatever reason in order to get these procedures, although they tend to be shorter procedures. In general, the moment that CHAMPION or CATALYST is positive, and these 2 devices and more become available, I think that there will be increasing demand that will force a lot of teams to adopt minimalist approaches to meet those increasing demands. As these procedures get increasingly beyond the hospital into ambulatory surgical centers (ASCs) outside the hospital, running a Lean team with just an echo tech and ICE catheter is going to be helpful.

It is not just any ICE, but we also must talk about the 4D capability of the NUVISION NAV^™ Ultrasound Catheter,   which is the ability to maintain the position of the ICE catheter in the LA in potentially 2 positions. That is what we typically do to the mid LA or super mitral; you have also heard of the pulmonary vein position, and the rest is done by digital steering from the console. So, that will continue to evolve and be adopted. I do not think that there is an alternative to that moving forward should these trials be positive or seen to be positive.

Thank you both for your time today!

Karim Al-Azizi, MD: Thank you for having us.

Nassir Marrouche, MD: Happy to be here. 

The transcripts were edited for clarity and length.

Footnotes:

*With the compatible CARTO™ 3 EP Navigation System.

# - Compared non-ICE guided procedures.

Disclosures: Drs Marrouche has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Marrouche reports grants or contracts from Abbott, Medtronic, Johnson & Johnson MedTech, Siemens, GE HealthCare, Boston Scientific, Sanofi, and Samsung; consulting fees from Johnson & Johnson MedTech, Boston Scientific, and AtriCure; payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing, or educational events from Abbott, Johnson & Johnson MedTech, Sanofi, and AtriCure; and is the founder of Marrek, Inc. Dr Marrouche is also named in a patent issued for MRI fibrosis imaging. Dr Al-Azizi reports that he serves as a consultant and advisory board member for Philips, Johnson & Johnson MedTech, and Abbott.

This content was published with support from Johnson & Johnson MedTech.

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This podcast is sponsored by Johnson & Johnson and its affiliates. The information contained in this podcast, and findings and conclusions expressed are those reached independently by the authors.

Important information: Prior to use, refer to the instructions for use supplied with this device for indications, contraindications, side effects, warnings and precautions. Caution: US law restricts this device to sale by or on the order of a physician.

© Johnson & Johnson and its affiliates 2025 

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