Stem Cells Show Early Promise for Heart Problems

At one year, the procedure proved safe and, the study authors said, resulted in improvements in pumping function and better quality of life.

The study, however, was not "blinded," meaning that any improvements could be due to a placebo effect. Decreases in the heart's size were minimal, Bonow said.

"This doesn't lead anywhere right now," Bonow said.

The study was funded by Mytogen Inc., a biotech company developing cell-based therapies.

The final study, which involved injecting patients' own stem cells into heart scar tissue, found that it did not affect heart muscle functioning.

"It was safe but didn't improve systolic function, didn't reduce infarct size and didn't influence global left ventricular function," said study lead author Dr. Manuel Galinanes, professor of cardiac surgery at the University of Leicester in England.

More information

Basic facts about stem cell therapy are provided by the U.S. National Institutes of Health.

SOURCES: Robert Bonow, M.D., immediate past president, American Heart Association, and Goldberg Distinguished Professor, Northwestern University Feinberg School of Medicine, and chief, division of cardiology, Northwestern Memorial Hospital, Chicago; Nov. 7, 2007, presentation, American Heart Association annual meeting, Orlando, Fla., with Heikki Huikuri, M.D., professor of medicine and director of the cardiology sector at the University of Oulu Hospital, Oulu, Finland, and Manuel Galinanes, M.D., professor of cardiac surgery, University of Leicester, U.K.