The Way Into An Arrhythmic Heart

EACH YEAR, SOME 250,000 Americans are struck down by ventricular tachycardia--an unexpected erratic beating of the lower, blood-pumping chambers of the heart. Using a single electrode probe to locate the source of the tachycardia during an episode may take hours, and that delay can threaten the patient's life.

But that may change with a new device scheduled to begin clinical trials soon in the U.S. The Arrhythmia Mapping System from Cardiac Pathways Corp. of Sunnyvale, Calif., is guided via a catheter through the aorta and into the heart's left ventricle. Once inside the chamber, its eight arms spread into the shape of a lemon-sized whisk, and 32 pairs of electrodes almost instantly measure how electrical impulses are being distributed throughout the heart.

Linked to a computer, the whisk locates damaged tissue, a cause of tachycardia, by detecting the tissue's abnormal electrical patterns. Doctors then insert another catheter that destroys the faulty tissue with heat generated by radio waves. Cardiac Pathways has conducted successful trials on four patients in the Netherlands, and the company recently received approval from the Food & Drug Administration for a preliminary study on 10 American patients, says Donald J. Santel, Cardiac Pathways' director of technical marketing. The U.S. tests are expected to continue for at least a year. The final product could be available in two years, says Santel.

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