A heart pump the size of a pencil eraser that made medical history by saving the life of a 62-year-old man could prevent the deaths of 150,000 people suffering acute heart failure or awaiting heart transplants each year, doctors said.

Surgeons at Texas Heart Institute announced Tuesday that the tiny Hemopump cardiac assist device kept the man's heart beating for two days last month while powerful drugs stopped his body from rejecting his transplanted heart. Tests now show the patient's heart is working normally."I've been in this medical center 20 years, and I think it's the most remarkable thing I've seen and experienced to date. That a device this small could take over the function of the human heart is really incredible," said Dr. O. Howard Frazier, director of the institute's cardiac transplant program.

"Miraculous is a strong word, but that's about what it is," Frazier said.

The Hemopump was implanted in a second Texas Heart Institute patient, but the man died of an irreversible heart condition. The Houston hospital now is the only facility using the device, but tests soon will begin at Mercy Hospital in Des Moines, Iowa, and Humana Hospital in Louisville, Ky., Hemopump inventor Dr. Richard Wampler said.

Wampler, who hopes to get federal approval to market the Hemopump in about 18 months, said it has the potential to save the lives of 150,000 patients suffering acute heart failure or awaiting human heart transplants each year.

Advantages of the Hemopump over other heart assist devices are its small size, the ease with which it can be implanted - it does not require major surgery - and it does not need an already beating heart in order to work effectively.

The pump was implanted April 26 in the left ventricle, or main pumping chamber, of the heart of the Colorado man, whose name and hometown were withheld at his request, and it was removed two days later.

Frazier said the rejection of the patient's transplanted heart was so great it no longer was functioning on its own before the implant.

The device, developed at Nimbus Medical Inc. of Rancho Cordova, Calif., is placed in the heart with a catheter inserted into the femoral artery through a small incision in the groin area. A tube that extends from the leg is hooked to a small, boxlike coupler that, in turn, is attached to a pumping mechanism.

The small pump rotates at 25,000 rpm to pull blood from the ventricle and send it to the rest of the body.