MIAMI – In a U.S. first, University of Miami doctors on Thursday injected potentially healing adult stem cells into a patient’s heart via catheter, rather than by open-heart surgery.

Sitting in a chair in his hospital room on Friday, patient Max S. Eaton, 66, was sounding chipper.

“I don’t want to be famous, I just want to be a healthy guy.”

If the early-stage research bears fruit, it could make repair from heart attacks much simpler, and more widely available and cheaper, possibly replacing open-heart surgery and heart transplants with an outpatient procedure, said Dr. Joshua M. Hare, the cardiologist who performed the procedure.

“Of course, the stem cells have to work,” he said.

The cells have worked in animals in early testing, but need to be tested in humans. That testing and required FDA approval would take at least five years, said Hare, who is chief of the cardiovascular division and director of the Interdisciplinary Stem Cell Institute at the University of Miami Medical School.

Eaton had a heart attack eight years ago and had started feeling short of breath recently, was awake and having dinner on Thursday an hour after the procedure, doctors said.

Cardiologist Alan W. Heldman used a long needle to extract bone marrow from Eaton’s hip, then injected the stem cells from the marrow into his heart through a catheter. The catheter, similar to that used in angioplasty or heart-valve repair, had a tiny, corkscrew-like wire at the end.

Heldman made an incision in Eaton’s groin and fed the catheter up the aorta into the heart, then steered it to the heart’s left ventricle, and into scar tissue caused by the old heart attack. He injected stem cells into 10 locations in that area.

“You steer it with the guidance of X-rays, and you screw it directly into the heart muscle,” Heldman said.

The cells used were bone marrow mononuclear cells. They are not the controversial embryonic stem cells, but immature adult cells that are believed to be able to divide, or differentiate into new heart tissue once they reach the heart’s damaged area. Other theories say they spur growth of blood cells into the heart.

“That’s one of the things we’re trying to learn in the study,” said Heldman, who is clinical chief of the Cardiovascular Division at the UM medical school.

Eaton is the first of eight patients who will be given the mononuclear stem cells in a run-up to a full trial designed to test the safety of the procedure.

The full trial will start as soon as the run-up testing is complete.

Sixty patients will take part in the full study.

with some getting the mononuclear cells, others getting mesenchymal cells – immature adult stem cells that are considered better at differentiating – and others will get placebo.

Hare and Heldman have successfully used the technique in animal trials; it is being tested in a handful of human patients in Argentina – with no conclusions yet. Eatonvolunteered for the study after reading about it on the Internet.

“I had a heart attack eight years ago, and recently I had been feeling bad again,” he said.

In a related study, Hare and Heldman in April injected stem cells directly into the heart of a Miami patient who was undergoing open-heart bypass surgery. They hope the new catheter procedure can replace the more severe open-heart surgery.

Heldman sees the new research as groundbreaking.

“When I was in med school, we were taught that once a heart was scarred from a heart attack, it was irreversible. In the last five years we’re starting to believe in regeneration.”