In experiments with dogs, Johns Hopkins researchers successfully used a 3D map of the heart and sensor-guided catheter to perform cardiac ablation, a mainstay treatment that stops abnormally fast and potentially fatal heartbeats, or arrhythmias.

The Hopkins findings, to be presented at the American Heart Association's Scientific Sessions 2005 on Nov. 13 in Dallas, Texas, provided information and technology used by the United States Food and Drug Administration to approve the system in March for testing in humans, now under way.

The Hopkins team created their own 3D models of each heart from images obtained by integrating and superimposing CT and MRI scans. Using an upgraded computer software program known as electro-anatomic mapping, the scientists are able to color-code the heart models' structures.

The scientists safely ablated, or destroyed, tiny areas of diseased heart tissue that facilitate rhythm disturbances, guided only by these anatomically precise, reconstructed 3D map.

During the procedure, a catheter containing a magnetic sensor in its tip is inserted through a vein in the dog's leg, then guided to the heart, where it is used to burn off the small part of heart muscle that gives rise to the errant signaling responsible for the arrhythmia.

A magnetic location pad was placed under the operating table and situated directly beneath the animal's body to detect the position of the catheter and compare it to the computer-generated image of the heart displayed on a screen.

"This is a significant improvement for patient safety and the performance of minimally invasive procedures in the heart," says study senior investigator and cardiologist Timm Dickfeld, M.D., Ph.D., an adjunct assistant professor at The Johns Hopkins University School of Medicine and its Heart Institute. Dickfeld
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Contact: David March
dmarch1@jhmi.edu
410-955-1534
Johns Hopkins Medical Institutions
13-Nov-2005