Thursday, July 24, 2008

New system makes heart procedure safer


By Amy Macavinta
Deseret News
Published: June 22, 2008
Hearts are racing with excitement this week because of new technology for cardiac patients with irregular heartbeats.

At least two Salt Lake area hospitals — Intermountain Medical Center and St. Mark's Hospital — are introducing a new procedure they believe to be safer and more effective, combining robotics, a 3-D mapping system and joysticks.

Dr. Peter Weiss, a cardiologist with Intermountain Medical Center, performed "stereotaxis" in Salt Lake City on a patient with multiple arrhythmias in the lower chambers on Tuesday. The walls of the lower chambers are not as smooth and more difficult to treat, so this case was more challenging than most. Even so, he was thrilled with the results. He did two more procedures Friday.

"The more I think about it, the more excited I am about it," he said. "I plan to use it on every case I can get my hands on, but where it is really likely to shine is in these more complex cases."

Stereotaxis is a robotic procedure that utilizes magnetic navigation and a 3-D mapping system to create a map of the heart, giving the cardiologist a detailed view of the inside of the heart, both anatomically and electrically.

A flexible catheter is inserted near the groin. By placing large magnets on the exterior of the patient's body, the doctor is able to use that magnetic field to pull the catheter to the proper location, using less force than the old method of manually pushing a rigid catheter through the body.

This reduces the chance of damaging heart tissue, a rare but possible complication doctors face with manual ablation therapy. And, because the catheter is more flexible, doctors are able to reach areas of the heart that were previously inaccessible.

All of this is done from a computer control room, just a few feet away from where the patient lies. Weiss said one of the key components to this system is the Odyssey, a flat-panel, high-definition monitor that allows the doctor to view the patients vital signs, ultrasounds, X-rays, real-time EKG data and a 3-D image of the interior of the heart — all on one screen. The cardiologist guides the catheter with a joystick, using those images to determine where treatment is needed.

"It is the integration of all the technology in one place that was the most helpful," he said.

The new technology provides an exciting alternative to traditional methods of treating arrythmia.

The heart beats as a result of electrical impulses that cause the heart to contract in a coordinated fashion, according to Dr. Scott Wall, a cardiologist with The Heart Center at St. Mark's Hospital. The impulses begin in the right, upper chamber then move through the other chambers in an orderly manner.

"In broad terms, an arrythmia is any derangement in that whole process," Wall said.

Arrhythmias are quite common — the heart beats in an irregular pattern — too slow, too fast. In some cases, arrythmia can be life-threatening. By entering the heart and cauterizing small lesions in areas where the electrical system is not functioning properly, doctors are able to bring the heart rhythm back to a normal rate.

Wall believes stereotaxis is especially promising for the treatment of atrial fibrillation, which will be an option available in the near future when an open irrigated tip catheter becomes available.

"This new procedure allows us to have the potential of a much more advanced approach" he said, " one that addresses the need for more advanced technology to deal with different anatomic variations of the heart and the different electrical variations."

Because the procedure is so new, it is not widely available. The electrophysiology lab at St. Mark's is under construction, and is expected to open June 30.