The University of Iowa Explores Opportunities with a New Technology: Paving a New Path for Heart Rhythm Management

The University of Iowa Cardiology Department recently acquired the Stereotaxis Laboratory System, a magnetic guidance system which allows for precise navigation to hard-to-reach vessels and helps to treat rhythm problems in the chambers of the heart. In fact, they are only the eleventh in the world to have this technology. In this article, the authors also describe their experience and goals in using this system. Matt Howard, Chairman of Neurosurgery at the University of Iowa, had a vision over a decade ago. He hoped to find new ways to move catheters inside blood vessels robotically. His hopes are now being realized after years of development. The concept was that manual manipulation of catheters inside blood vessels was possible, but an intricate network of non-linear three-dimensional anatomy could be too challenging to navigate. Using a magnetically guided approach, Howard and colleagues hypothesized that magnetically active guides could be placed anywhere in the body, no matter how complex the path. Magnetic catheter guidance was born, and the concept has become a reality. The company Stereotaxis was founded in 1990 to further develop the pioneering work in magnetic instrument guidance by researchers at the University of Virginia, University of Iowa, and the University of Washington. Now catheter manipulation can be performed with millimeter accuracy through some of the most complex anatomy imaginable. Those who shared his vision realized that there might be potential opportunities in cardiac electrophysiology and interventional cardiology. The University of Iowa Hospitals and Clinics shared Matt s vision, and have just completed the eighth Stereotaxis Laboratory System installation in the country. They are the eleventh in the world to have this technology. The University of Iowa laboratory is now completely revamped. The Stereotaxis System is accompanied with a state-of-the-art Siemens fluoroscopic system, providing some of the clearest fluoroscopic images available as part of a fully integrated digital system. In fact, the floor needed to be reinforced to allow for the 8,000-pound magnets to be placed, and the ventilation system needed to be augmented. In addition, a control room with audio capabilities needed to be placed. The laboratory has been operational since the second week of January 2004. The University of Iowa s second-generation Stereotaxis equipment allows for remote navigation of EP catheters and wires utilizing permanent magnets, fluoroscopy and complex computer algorithms. The process for navigation is straightforward with a moderate learning curve. The concept is that movements of a strong magnetic field in three dimensions can position magnetized equipment inside the body. This is proving to be possible with extreme accuracy. The laboratory personnel are becoming acquainted with the concept of a control room that allows the electrophysiologist to perform the majority of the electrophysiology test effectively and with a minimum of fluoroscopy exposure. The control room is a place where all the EP data can be reviewed and programmed stimulation can be performed. It offers the potential for accurate catheter manipulation from a distance, another concept requiring adjustment from prior practices. Support staff have found it easier to learn to use the new hardware and software than commonly used three-dimensional mapping systems. Navigation requires the use of catheters or wires that have a small magnet or series of magnets embedded on the distal tip. Currently, a quadripolar catheter and a line of wires of various lengths and characteristics are FDA approved. Several devices, including ablation catheters and wires to traverse total coronary occlusions, are being evaluated. To navigate in the heart and adjacent structures, a magnetically tipped wire or EP catheter is advanced to the heart chamber or vessel. After obtaining LAO/RAO fluoroscopy images with at least 40 degrees of separation the two permanent magnets, which are about the size of small jet engines and are located on opposite sides of the bed, are rotated into a navigate position snuggling up to the patient. At this point, in utilizing a computer, the tip of the device can be deflected by magnetic guidance in practically any direction. Catheter manipulation is as simple as drawing an arrow using computer skills and a standard mouse on a saved fluoroscopic image displayed on the monitor, indicating the direction the catheter and/or wire is to go. A second arrow is drawn on the complimentary stored fluoroscopy view and the magnets are activated. Then, the two external magnets rotate independently. This alters the magnetic field at the catheter tip, causing it to deflect in the direction of the arrows or vectors. We have used this method with good success for placement of CS leads into branches. Utilizing magnetic guidance, we were able to navigate to multiple CS branches with ease in just less than 20 minutes. The advantages of this technology may be many. All the potential uses are not currently known. Catheters can be placed and advanced from a navigation workstation in the control room and a slave in the laboratory itself. Navigation is real-time and is two- and three-dimensional. The newer system offers an ease of use and operator friendliness. One goal is to develop the system s target-based navigation capabilities. The goal is not only to use the equipment to place electrophysiology catheters in an open loop format, but to have a closed-loop system with localization feedback for full chamber mapping, and ultimately, catheter placement in any position for ablation and device implantation. The technology is capable of interfacing with CT and MRI images so that in three dimensions, it is possible to navigate a catheter to a place in the heart with accuracy and without concern about the difficulty of the anatomy. Ultimately, this technology may be able to be combined with other electro-anatomical approaches. A template map can be used to direct catheters based on accurate reconstructed or otherwise obtained three-dimensional images. The potential uses to consider include placement of leads for biventricular devices and for completion of complex ablation procedures. We do not yet know the distinct advantages of this system. It is not yet clear if this technology will offer increased safety and/or efficacy or will minimize fluoroscopy time, procedure time or decrease risk to patients. We are planning to design and contribute to collaborative protocols to explore uses of this new technology. The University of Iowa team is excited about the possibilities and the opportunities it will bring to electrophysiology and interventional catheter procedures. University of Iowa researchers from the Neurosurgery Department and Pulmonary Division are looking at ways this technology may be applicable, effective, and useful. The new technology is greeted with excitement and anticipation but the transition to a new approach has also been a challenge. The staff is expecting a steep learning curve, and there is some resistance in giving up tried and true approaches to ablation and lead placement. The use of magnetic robotic guidance is not yet established for any one procedure with certainty. The room setup is much different with two active and large magnets. The advancements in electrophysiology in the past decade are nothing short of astounding. New technological possibilities may augment to almost exponential growth in therapeutic advances in cardiac electrophysiology. Perhaps one of the greatest long-term challenges will be to change the vision of electrophysiology from standard, known and accepted treatment approaches that require human technical expertise to a new automated horizon at which new therapeutic ideas presently only imaginable can become manifest on a large scale. This new technology may require new ways of thinking to accomplish old tasks and those that have not been possible up to now.