A Stem-Cell Prospect for Ailing Hearts

Valentin Fulga dropped out of medicine twice to pursue more-challenging research, but now it looks as though his change of heart could result in saving the lives of thousands--perhaps millions--of cardiac patients. Dr. Fulga, 47, is the scientific brain behind a new treatment for heart disease that is exciting the medical world even though it has yet to undergo full clinical testing.

More than 60 people in need of heart transplants or major surgery have been treated using the new procedure. That's a small number, but the results are nonetheless stunning: all of them improved. That's why TheraVitae, the privately owned company...