Magnetically guided catheter aids radio frequency ablation treatment of heart

21 April 2006

A remotely-controlled catheter device guided by magnetic fields provides a safe and practical method for delivering radio frequency ablation treatment in the hearts of patients with atrial fibrillation, according to a new study in the April 4, 2006, issue of the Journal of the American College of Cardiology.

“Based on our experience with remote navigation and ablation technology, a new era in interventional electrophysiology is beginning as magnetic, very soft catheters can be navigated in the heart more precisely and safely than manual catheters without risk of major complications, even in less experienced centers,” said Carlo Pappone, M.D., Ph.D. from the Department of Electrophysiology, San Raffaele University Hospital in Milan, Italy.

Atrial fibrillation is an abnormal heart rhythm in which the upper chambers of the heart flutter, and do not pump blood normally. If the condition cannot be managed with medications, some patients are treated with radio frequency ablation. The technique uses a high energy pulse to destroy a small area of heart muscle cells, in order to prevent them from conducting nerve signals that trigger fibrillation.

Typically the radio frequency pulse is emitted by from the tip of a catheter threaded through blood vessels into the heart until it is positioned next to the target area. Conventional catheters are somewhat stiff, so they can be pushed and pulled through blood vessels, and their tips can be curled and pointed by an operator standing by the patient. The device tested in this trial uses a very soft, limp tip that has a magnet on the end. Rather than manually pointing the catheter tip, the operator of this device uses a computer to control a magnetic field that robotically moves the catheter tip. The principle is the same as a compass needle pointing to magnetic north; allowing this device to steer the magnetic catheter in three dimensions to a target visualized on 3-D scans of the patient's heart.

“Catheter ablation for atrial fibrillation is now an important treatment for this common disorder, but the current strategy of manual catheter manipulation is highly operator-dependent, with a long and variable learning curve and a great potential for both inefficacy and complications in inexperienced hands. Robotic navigation may increase the ability of inexperienced operators to perform this procedure easily and safely, as it is most dependent on a well-trained team rather than on a single operator,” Dr. Pappone said.

Since catheter procedures of this type require frequent use of X-rays to track the location of the target and the catheter tip, another advantage of remote navigation is that the operator can work from a shielded control room, rather than having to stand next to the patient for several hours while wearing protective lead aprons.

This first trial of the robotic magnetic navigation system in patients with atrial fibrillation involved 40 participants whose conditions were not adequately controlled by medication. After encountering some difficulties in the first three patients, the researchers said the remaining procedures went smoothly. In all, the catheter tip was successfully guided by magnetic navigation to the target and radio frequency ablation was applied in 38 of the 40 study participants. There were no reported complications during the procedures.

“Based on our results, we believe that incorporation of remote navigation and ablation in the electrophysiology laboratory may represent a true revolution regardless of age and experience of the operators leading to a seismic change in electrophysiologic paradigms for many laboratories worldwide. People always have had a love/hate relationship with robots, but this psychological barrier must be overcome. After performing more than 10,000 procedures with manually deflectable catheters, I have become enthusiastic for this emerging field,” Dr. Pappone said.

Further information : The full study is available on the ACC website

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