Tell us about your EP program. What types of procedures do you most commonly perform? What is the case volume?
I’ve been at Northwestern for 10 years. We have seven faculty members, six of which are independently performing atrial fibrillation (AF) ablation, and four fellows. We have three labs, and our cardiovascular program is ranked among the top 10 in the country for cardiology and heart surgery. Our lab is equipped with advanced electroanatomical mapping systems and intracardiac echocardiography (ICE). There are very few things we don’t have access to in our lab.
We perform approximately 700 EP procedures and 700 device implantations per year. Most of our EP procedures are ablations; I would estimate we perform about 350 AF ablations in a year. Other than AF ablation procedures, it’s about an even split for other EP procedures.
How long have you been using a radiofrequency (RF) needle for transseptal? What prompted you to transition from mechanical alternatives?
I have been using a RF needle for transseptal puncture since before joining Northwestern. Another EP had referred me a patient with a difficult transseptal puncture for a left-sided ablation, and it was at this time that I began using an RF needle (NRG® Transseptal Needle, Baylis Medical). I was pleased to learn later that this case was the first-ever transseptal puncture using this RF needle.
Since then, I have become more interested in powered transseptals. One can make the argument that they are only useful for difficult cases, such as for a thick or redundant septum. However, we have started using them for all transseptal punctures, and now everyone in our program uses the same approach.
I felt it was a very logical change from mechanical needles. During the mid 2000s, we started to see more challenging procedures and have more redo procedures. With additional redo procedures, we realized there was a need to try something other than the standard needle. It seemed unnecessary to struggle with the outliers using a standard needle when we could routinely use the RF needle.
What was the learning curve with the RF needle?
It was extremely easy to use in that first experience. It has a trivial learning curve. It’s a little duller than a standard needle. It also doesn’t have end holes, just side holes. This would make it difficult to stain the septum with contrast, but I don’t think many of us use contrast anymore given advancements in technology.
What are your biggest challenges when crossing transseptal? How does this device impact the case outcome?
The RF needle allows cases to be more predictable. It can be difficult to predict which cases are going to be challenging. The transseptal puncture is a critical part of the procedure, and although we trivialize it, there are many difficult cases. I prefer to simplify the transseptal part so that I can focus on the rest of the procedure.
The needle almost always goes through with the first delivery of RF. Sometimes, we want to strategically target a part of the septum that is thicker. For example, I recently had a left atrial appendage closure case where we wanted to make a very low transseptal puncture for a second attempt, and we went through a pretty thick area. This would have been much more difficult with a standard needle.
What would you say to colleagues who don’t currently use the NRG Transseptal Needle?
A lot of times, it comes down to cost. I’m sensitive to that; our value analysis committee at Northwestern would have had to approve this if we hadn’t already started using the technology many years ago. I would tell other EPs that it’s a very low additional cost, and I think it’s worth it to have an RF needle that is predictably effective. I feel fortunate to be able to use it.
What are the benefits of RF compared to mechanical alternatives?
There are two main reasons. Number one, it predictably penetrates areas that are otherwise very challenging to cross with a standard needle. Sometimes you can encounter a really thick lipomatous septum that can be hard to cross. Other times when doing a redo procedure, the fossa may not look thick on the ultrasound, but in reality, it’s very difficult to penetrate. This is because redo procedures can mean there are scars that are not immediately evident on ultrasound.
Second, the mechanical effort required to cross is much lower using the RF needle — one is much less likely to go too far. The biggest concern with the mechanical needle is that you’re pushing and pushing, and then as soon as it gives, you lunge forward. I view it as a safety feature of the NRG needle to not have to push too hard. You don’t get into a scenario where you end up overshooting with the tip of the needle.
Off-label transseptal puncture techniques are out there, potentially at the expense of patient safety. What would you say to the physician community about transseptal crossing options?
There are some who are more selective about which procedures they use the NRG Transseptal Needle with, or who will only use it when the mechanical one doesn’t work. Oftentimes, they end up having to hook up a Bovie [electrocautery generator]. I recently published a paper showing that this type of procedure can end up with “coring” [of septal tissue].1 What this means is that when you electrify the open sharp end of a regular mechanical needle, a piece of tissue can be cut out and expelled into the left side of the heart. Honestly, when you see it, it’s very difficult to ignore. Even if an operator has never seen a patient have a stroke from coring the septum, this technique should still be avoided. Based on what we saw in our study, I would not recommend the use of a Bovie technique.
Disclosure: Dr. Bradley Knight is a consultant for Baylis Medical on clinical topics and medical education. He is financially compensated for providing the expertise, training, and consultation.
About Dr. Bradley Knight
Dr. Bradley Knight is the Chester C. and Deborah M. Cooley Distinguished Professor of Cardiology at Northwestern University, and has been the Director of Cardiac Electrophysiology at the Bluhm Cardiovascular Institute at Northwestern Memorial Hospital since November 1, 2009. He earned his BSPH at the University of North Carolina in Chapel Hill, and his MD at the Ohio State University. After completing his training in Medicine, Cardiology, and Cardiac Electrophysiology at the University of Michigan, he joined the Michigan faculty in 1997. He later served as the Director of Cardiac Electrophysiology at the University of Chicago from 2002 to 2009.
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This article was published with support from Baylis Medical.
- Greenstein E, Passman R, Lin AC, Knight BP. Incidence of tissue coring during transseptal catheterization when using electrocautery and a standard transseptal needle. Circ Arrhythm Electrophysiol. 2012;5(2):341-344.