Considerations for Implementing Esophageal Temperature Management During Radiofrequency Ablation for Atrial Fibrillation

EP LAB DIGEST. 2023;23(6):14-15.

In this feature interview, EP Lab Digest talks with Danya Willms, RCES, lead electrophysiology (EP) technologist at Sharp Memorial Hospital in San Diego, California, about her experience with the EnsoETM esophageal cooling device (Attune Medical).

Tell us about your practice, including lab staff, types of patients, average number of radiofrequency (RF) ablations per year, and typical equipment used for ablations.

At Sharp Memorial Hospital, there is 1 EP laboratory and we are looking to open a second EP room soon. We perform roughly 400 ablations per year, and we also perform pacemaker device implantations, laser lead extractions, and Watchman device (Boston Scientific) implants.

We have 4 full-time and 2 part-time electrophysiologists. There are 5 cardiovascular technologists; 3 are dedicated to EP and the other 2 split their time between the EP and cardiac catheterization laboratories. We have 1 radiologic technologist and 2 registered nurses who are dedicated to the EP lab. Our lab uses the Carto system (Biosense Webster, Inc, a Johnson & Johnson company) and EnsoETM esophageal cooling device for every atrial fibrillation (AF) ablation.

What initially led you to try using the EnsoETM during your RF ablation cases? Please share your thoughts on the clinical findings so far, as well as impact on safety, efficiency, and efficacy.

Prior to our use of the EnsoETM esophageal cooling device, we were performing AF ablations using a multi-sensor probe. We were doing everything we could to be careful. For example, we used low power on the posterior wall and would avoid lesions near the esophagus. However, even with use of a temperature probe, we had a patient with an atrio-esophageal fistula. Our goal as a lab was to never see that happen again.

Shortly after that, we met with Attune Medical to explore esophageal cooling during these procedures. Their initial animal studies showed this was a safe option for these procedures, so that is what drew us to begin using active esophageal cooling. We started with Attune Medical in September 2019, and have now completed over 500 active esophageal cooling procedures since then. There is a large body of clinical data on the safety and efficacy of esophageal cooling. We were part of some cohort comparison studies that clearly indicated a decrease in procedure time. Our data show that it was approximately a 23% procedure time reduction. We have also found a double-digit improvement in freedom from atrial arrhythmias at 1 year and a 12% reduction in the need for redo ablations. Therefore, we have experienced great results.

Tell us about the effect on your workflow, including procedural efficiency and procedural efficacy, utilization of fluoroscopy, availability of support, and staff morale.

Attune Medical did the in-service training with both our EP lab staff and anesthesiologists. In our lab, the anesthesiologists place the cooling device. Initially, Attune Medical provided us with clinical support for every case, helping us with any questions. We also shared the study data with the anesthesia department to ensure their buy-in and support for these cases.

It has been a seamless introduction into the lab. When placing the EnsoETM esophageal cooling device, we found there was no increase in time compared to a temperature probe. We have anesthesia place the system for us, so there was no change in staff. Our lab uses a closed-loop solution, so we all know when we should start to actively cool and when to stop post procedure. We all cross-monitor each other to make sure everything is happening at the appropriate time.

With the temperature probe, the scrub tech would have to monitor all temperature changes happening while we were ablating and notify the physician of changes. This was a constant disruption to our lesion placement and tied up one person on the team to only monitoring temperature changes. Freeing up the alarm allows all staff to be fully engaged in the case and shortens procedure time.

Once we began using esophageal cooling, we immediately started to see the benefits, such as case reduction time with the first case. With luminal esophageal temperature monitoring, every time the alarms occurred, we were coming off burning, and we would have to switch to a different part of the left atrium to burn. With the EnsoETM esophageal cooling device, we can do continuous lesions with no stopping. With continuous lesions, we have seen increased efficacy of the lesion set. We have also seen fewer redo procedures due to return of atrial arrhythmias.

Regarding fluoroscopy, we had already switched to a zero-fluoroscopy approach in our lab, and the addition of the EnsoETM does not add the use of fluoroscopy. We can clearly identify the cooling probe with an intracardiac echocardiography catheter and upload those images to Carto, so the location of the esophagus can be defined on our left atrial maps.

Another benefit is that the use of active esophageal cooling has helped us achieve more same-day patient discharge. Since our procedures are shorter, we are able to complete them earlier in the day, which allows us to feel more comfortable discharging those patients home.

Finally, we have noticed fewer post-operative complications with the use of esophageal cooling, including a decrease in chest pain and gastroparesis.

Can you describe the process of implementing the EnsoETM into your lab? For example, discuss use of capital equipment, clinical training requirements, company support, and procedural approval.

We utilized the Blanketrol (Gentherm) system with the EnsoETM, and Sharp already had a number of machines onsite, so there was no capital outlay required. We worked with our other departments to get a full-time machine assigned to EP, which was simple to do.

Clinical training requirements were trivial, since the device is placed like a standard orogastric tube that patients receive under anesthesia. No change to the ablation procedure was necessary.

There has really been no difference in cost between the EnsoETM and the temperature probe that we previously used, so that was an easy sell for us, as we were not increasing our expense for procedures.

The support from Attune Medical has also been fantastic. They provided all the necessary clinical support and representatives were onsite for our initial procedures. Now if we come across something that we do not understand or have a question about, they are only a phone call away. They are very attentive and knowledgeable. There are a number of support staff, so if our direct representative is not available, there are multiple people within their team that can offer support.

Procedural approval involved asking anesthesia for buy-in on the product. Data from the early studies were available when we started, and with the large body of clinical data now available, anesthesia is completely on board. We never had any pushback from them, so it was an easy transition.

What are the primary patient-oriented outcome improvements?

Our clinical data have shown a significant decrease in recurrent atrial arrhythmias within the first year, a shorter procedure time, and a reduction in the need for redo procedures. We have also seen a decrease in chest discomfort, gastroparesis, and pericarditis in our patients, facilitating an increase in same-day discharge and generally improved patient satisfaction.

Did you see secondary improvements in patient symptoms? Do you see any new complaints?

We have not seen any new complaints from our patients postop. It has not negatively impacted patient quality care or added to any complaints from patients, but rather has contributed to improvements in this area.

What do you attribute the difference in the recurrence rates of AF in your ablated patients to when using the EnsoETM?

As mentioned earlier, we have seen a decrease in our patients coming back for redo ablations since we have started with the EnsoETM. A lot of that is attributed to us having that 100% cooling through the entire procedure, so we are able to achieve continuous lesions and get full-thickness burns on all lesions. We attribute much of that success to the EnsoETM.

Are there any other systemic effects that you are seeing at your site?

Yes, since our procedures are shorter in duration, we now have better lab utilization, which has led to an increase in the number of cases that we can provide in our lab throughout the year.  We believe that with the addition of a second lab this year, we will be able to further optimize our utilization and increase our procedure volumes even more efficiently. 

Disclosure: Ms Willms has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. She reports consulting fees, honoraria, and support for attending meetings and/or travel from Attune Medical.