In this interview, EP Lab Digest® speaks with William H. Spear, MD, FACC, FHRS from Advocate Christ Medical Center (ACMC) in Oak Lawn, Illinois about his use of the recently acquired Stereotaxis technology Vdrive™ with V-Sono™.
How did you become interested in EP?
I became interested back in medical school. I was really interested in the physiology of cardiology and especially with the technology involved in electrophysiology. I have a passion for utilizing technology to make people’s lives healthier and better. I think that is what specifically attracted me to EP.
How long has Stereotaxis been installed at ACMC? Describe the different Stereotaxis technologies available there.
We’ve had Stereotaxis since 2008. We started with the Niobe® Remote Magnetic Navigation system, and recently updated to the Epoch™ solution, which brings a number of features to the table that weren’t previously available. First, the new system moves the catheter faster and with continuous motion; before, you had to move the catheter relatively slowly with segmented movements, and now it’s a very fluid motion of the catheter. In addition to the Epoch solution, we just recently installed Vdrive with V-Sono — there are only a couple of labs in North America that currently have this installed. We were the first in North America to launch this technology.
How many cases do you perform each week using Stereotaxis? Approximately how many Stereotaxis cases have you performed to date? What types of arrhythmias are treated?
I perform 4–8 cases a week using robotic technology. To date, I have performed close to 600 robotic ablations.
Where Stereotaxis robotic technology really excels is in the area of complex arrhythmias. There are great benefits in utilizing robotic technology for the treatment of atrial fibrillation (AF) and ventricular tachycardia (VT), in that you can actually exceed the results that you might get using a manual approach. It can be used for other types of arrhythmias as well — SVTs such as accessory pathways or AV nodal reentry — but it’s not absolutely necessary for those procedures. However, when it comes to the treatment of complex arrhythmias, I really think it gives you an advantage over a manual approach.
Tell us about the newly approved Vdrive with V-Sono. How does it work, and what has been your initial experience with it?
The Vdrive is a robotic arm that attaches to the table and is able to control the ultrasound catheter robotically. Essentially, you place the ultrasound catheter into the right atrium just as you would during any other case, but then you connect the handle to the robotic arm and snap it in. Once you leave the room to control the ablation catheter, you’re also able to control the ultrasound catheter using the joystick. In the past, when you placed an ultrasound catheter, the only time you could control it was when you walked back into the room, which kind of negated the robotic benefits of being comfortably seated in a control area and performing the ablation. Now, we’re able to visualize true catheter-to-tissue contact during a robotic ablation, which is important, because when you’re doing a robotic versus a manual ablation, you lose that feel for the contact with the catheter tip. We can visualize whether we’re in contact with the tissue and whether our ablation lesions are going to be effective or not. It has added a dimension that we didn’t have before. By combining remote magnetic navigation and a mechanical arm to control the ultrasound catheter, we’re one step closer to making the entire procedure robotic.
How did you utilize the ICE catheter before V-Sono? Has it differed since adding V-Sono?
Absolutely. Prior to adding V-Sono, we would place the ICE catheter at the beginning of the procedure, and utilize it for the transseptal; it is very important which location you choose to cross into the left atrium. After the transspetal, the ultrasound catheter would just sit there, and whenever we’d adjust the Lasso catheter, we’d manually move the ICE catheter to confirm we were in a particular vein. If we ever had a question about a complication, we’d have to go back into the room and make sure there was no pericardial effusion. That has changed quite a bit, because now as soon as we place the ultrasound catheter into the robotic arm, we’re able to get very stable ultrasound images without having to hold the catheter. Therefore, it assists in the transseptal as far as catheter stability and keeping the area of the septum visualized. During the procedure, it allows us to assess the adequacy of the lesion formation by looking for the catheter-to-tissue contact during the ablation, and we can also monitor real time for complications such as pericardial effusion or thrombus formation on any of the catheters during the procedure. So, how we utilize the ultrasound catheter has changed quite a bit, and I think it’s actually made us more efficient. Prior to V-Sono we may have been ablating in areas where we did not actually have tissue contact, specifically near the right inferior pulmonary vein. Now, we can see if we’re in contact; if we’re floating, we’ll immediately come off of RF and reposition, or adjust the sheath to make sure we have appropriate contact so we’re not wasting RF. It’s made us more efficient in the way we approach the right-sided pulmonary veins.
Do you have preference for a specific ICE catheter to use with V-Sono?
I’ve switched to Biosense Webster’s 10 French SoundStar Eco catheter; I believe I’ve been getting slightly better imaging quality with the 10 Fr SoundStar and it is more environmentally friendly.
Can you share some data points on how V-Sono has improved clinical procedures? What positive aspects surprised you?
When we moved from Niobe to Epoch, we saw a considerable amount of time savings, in part because we were able to change the way we did our mapping. Prior to the Epoch solution, we were mapping with either the Lasso FAM or Biosense Webster’s CartoSound. In switching to the Epoch solution, we are now able to create maps using the 3.5 mm irrigated tip catheter and continuous motion of the catheter, thus recreating the anatomy fairly quickly. The accuracy of this type of mapping is incredible. It creates MRI-quality imaging of the left atrium. This costs us a couple of minutes in time in mapping, but it decreases our total procedure time by 45–60 minutes depending on the type of ablation, whether it is for paroxysmal or persistent AF.
In using V-Sono, we’ve further improved our ablation times and have seen decreased RF times; I believe this is because we’re wasting less ineffective RF, especially near the right-sided pulmonary veins. Instead of ablating in areas where we thought we were in contact, we are assessing true contact, coming off RF and repositioning the catheter, and making more effective lesions. Furthermore, we have been able to reduce our fluoroscopy time because of the accuracy of our maps; using a 3.5 mm tip catheter, we can create MRI-quality maps without the need for radiation or fluoroscopy, and because of this, we rarely have to step on fluoroscopy. When we went from Niobe to Epoch we were able to reduce our radiation time by about 64 percent, or about 3–5 minutes. Now with V-Sono, once again we’re able to reduce it slightly, but we’re already so low that we’re seeing minimal gains of about 1 minute. So, in a procedure what may have taken us anywhere from 3–4 minutes of fluoro might now take us 2–3.
How has V-Sono changed the way you approach a procedure?
V-Sono gives you an advantage in the robotic procedure because it allows you to monitor real-time catheter-to-tissue contact and complications. Intraprocedurally this has changed how I approach a procedure in general, since we’re now able to monitor more closely during the procedure, so it has increased the overall safety.
Was adding Vdrive with V-Sono a natural step?
Absolutely, the V-Sono is the next step in the progression to making these procedures completely robotic. We need to have control over all of the catheters that are frequently moved, such as the ultrasound, Lasso and ablation catheters — and I think we’re close to getting to that point, where once we place the catheters, the need to go back into the room to reposition catheters is going to be very minimal.
Describe the improvements Stereotaxis has provided in areas of clinical approach, patient care and outcome.
A great example for improved clinical approach is in the treatment of VT. I prefer to do complex arrhythmias such as ischemic VT robotically versus manually — it has made me better at approaching these arrhythmias because of the ability to be comfortable during the procedure, to take the time to analyze electrograms, pacing maneuvers, etc., and it has improved our outcomes for VT ablation. In regard to patient care and outcome, there’s really no argument on whether catheter ablation with a Stereotaxis system is safer than a manual ablation — we see much smaller perforation rates with the remote magnetic technology than we do in manual cases. We can get the equivalent and in some cases better results with robotic technology, and it’s safer for patients, especially in reducing their cumulative radiation exposure. This is important as we continue to increase our volume of complex ablations.
What are the key aspects that have contributed to the success of your robotics program? Have you had patients travel from afar to seek out your leadership in EP robotics? What about attracting new fellows?
One of the key reasons why we’ve been successful is that we’ve established a very strong reputation for safety in regard to our procedures. Our safety record is probably one of the best in the country because we’ve utilized Stereotaxis, and this has helped to drive future referrals to our program. Secondly, our outcomes are excellent as well, so this has driven further referrals to the program and helped things grow tremendously. We’ve had referrals from across the country from patients coming in to have ablation procedures, specifically because of our strengths in robotics, and I think as the word spreads, patients will realize the importance of these factors. As far as attracting new fellows, we just started our fellowship program for cardiac EP, so I would imagine that this will draw fellows who are interested in robotics.
For those physicians who are contemplating the Stereotaxis Epoch platform, what would you say to them?
It’s absolutely a game changer in regard to the way you approach complex ablation. If you have a high volume of ablations, it’s definitely a beneficial way to approach it versus the manual approach of having to stand at the bedside for multiple hours every week. If you’re seriously considering starting or growing a complex ablation program, I think robotics is the way to go.
Disclosure: Dr. Spear reports consultancy with Stereotaxis.