The 10 patients (7 men and 3 women, average age 51 years) were in severe heart failure and facing imminent death in intensive care units; they were too small physically to qualify for any of the other bridge-to-transplant left ventricular assist devices, says O.H. Frazier, M.D., lead investigator for the device that has been under development for more than a decade at the Texas Heart Institute.

The study found that the Jarvik 2000 increased cardiac index by 43 percent within 48 hours of implantation, making inotropic drugs unnecessary. Of the 10 patients, 8 underwent physical therapy and improved from severe (New York Heart Association Class IV) to mild heart failure (Class I). Although the study protocol required the patients to remain at the hospital, they were able to resume normal activities such as walking outdoors while awaiting their transplants. The device was used for an average of 84 days.

This article follows a study published in Circulation's May 14 issue in which Frazier and Stephen Westaby, Ph.D., M.S., implanted the Jarvik 2000 as non-bridge therapy in four patients in the United Kingdom who were not eligible for transplant. Three of them are still alive, the first nearing two years after implantation.

"At this early stage, the Jarvik 2000 seems to hold much promise for many patients with heart failure," writes noted heart surgeon Denton A. Cooley, M.D., the founder of the Texas Heart Institute, in an editorial that accompanies the current Circulation article. "This [study] showed that it can safely support patients to transplantation."

The American Heart Association estimates that about 4.8 million Americans live with congestive heart failure and than 50,000 affected people die from the condition each year.

In contrast to the other devices, which require fairly extensive implant operations, the Jarvik 2000 is small enough to be implanted inside the ventricle during a procedure that requires little or no time on a heart bypass machine, Frazier says. The device is made of titanium with only one moving part -- a tiny vaned impeller -- in an attempt to reduce the chances of blood clot formation and bacterial adhesion.

No thrombi were seen in the seven devices that were removed during the subsequent transplant procedures. Nine of the ten patients had received drugs to guard against thrombi. The tenth patient, who had contraindications to the medication, was supported for 244 days without an anticoagulant.

The device presented only three minor technical problems during a cumulative total of 812 days of support. All problems were resolved quickly with no adverse consequences.

The device features electrical wires that thread out of the body and attach to a rechargeable battery pack that fits in a bag that can be worn on the waist or carried on the shoulder as well as a speed control that the patient can adjust to accommodate increased physical activity.

"The Jarvik 2000 was designed to be reliable, easy to implant, and simple to operate," researchers write. "In our series of 10 patients, the device met all of these goals."