A Perfect Fit for Patients and Clinicians: Improving Quality of Care With Stereotaxis and the EnSite® System Navigation

A Simple, Straightforward Combination

We began using the two systems together in January 2006, when the Stereotaxis catheter was approved for use. Both the EnSite Array non-contact catheter and EnSite NavX navigation and visualization technology have been in use at the Minneapolis Heart Institute/Abbott since the products were available. The EnSite System and Stereotaxis have worked together seamlessly from day one, providing a great union of clinical accuracy, improved safety and procedural efficiency. Due to their inherent stiffness, traditional electrophysiology catheters can stretch tissue and cause distortion of cardiac structures. This can cause false space when creating chamber geometry. One of the unique performance characteristics of the Stereotaxis catheter is that it's a very floppy, forgiving catheter. It has become evident that the geometries created by magnetic manipulation are actually more demonstrative of the atrial structure because the softer catheters reduce the potential for tenting of the atrial tissue.

Better for Patients, Better for Staff

Stereotaxis catheters depend on magnets to move rather than internal wires, so they do not have the same requirements for catheter pushability and torqueability to achieve and maintain position. With this new method of magnetic catheter manipulation, we can access difficult areas of the chamber quickly, safely and easily, which helps create a clearly defined chamber model. Preset and memory features of Stereotaxis navigation also allow for quick access and return to difficult locations. The combination of a catheter with less potential for perforation and the ability of the EnSite System to quickly capture anatomic detail has also allowed us to achieve a reduction in overall procedure and fluoro time. In our practice, using traditional catheters and standard mapping techniques, the average ablation patient required approximately 60 minutes of fluoroscopy time. However, the combination of the advanced systems has allowed us to reduce fluoro time to approximately 15 minutes per patient. Most of the fluoro time is comprised of initial catheter placement and transseptal puncture. Once ablation begins, we rely entirely on the EnSite System model. This is a tremendous benefit to our staff, dramatically reducing their total fluoro time, especially when you consider that we are often performing 1 - 2 atrial fibrillation ablation procedures per day. Along with a reduced reliance on fluoro, multiple EnSite System monitors allow all members of our staff to view the procedure. At a minimum, catheter movement is being observed by the physician on the Stereotaxis controls, the EnSite System operator, and the person manning the RF generator. More eyes on the catheter mean less chance of ablating in an inappropriate location and less risk for the patient.

New and Unique Capabilities

Both Stereotaxis and the EnSite System offer unique capabilities to facilitate more efficient and effective procedures. For example, the Stereotaxis system offers a bulls eye feature, where at the push of a button the catheter will spin in a programmable radius to define a chamber or pulmonary vein. The EnSite System can also gather mapping points continuously as the Stereotaxis catheter progresses on its radial path around the vein ostia, rather than capturing only the 10 points provided by a traditional circular mapping catheter. This feature allows us to better map and isolate the ostia of the pulmonary veins, in many cases making it possible to avoid using an additional catheter, a second sheath, and performing a second transseptal puncture.

Things to Remember

When bringing together remote navigation and 3-D mapping, begin by using typical views. It's challenging to tell the computer where to go if you haven't orientated your geometry within the navigation system in a way that corresponds well to the mapping system. Begin by orienting the EnSite System to real RAO and LAO, then orient the Stereotaxis system in the same manner. This way, when you move the Stereotaxis navigation to the right, the catheter moves to the right. By adding the esophagus to the 3-D geometry, it is possible to monitor catheter proximity to the esophagus without significant use of fluoroscopy. It can also prove very useful to create a model of the esophagus using an EP catheter, enabling you to add this structure to your 3-D geometry. We then place a temperature probe in the esophagus and monitor for temperature increases when nearing the esophagus. Because we can depend on the detail of the map to show clearly when we're approaching the esophagus, this has also contributed to a significant reduction in flouro use. Finally, understand that there is a learning curve to working with these systems. It takes time in the beginning, but there is a payoff. In less than one year of use, our team has reduced the average atrial fibrillation ablation time by 1 hour.