Doctors are using a patient's own stem cells to repair his damaged heart.

It's an experiment being done at Cedars-Sinai Heart Institute in Los Angeles. A 39-year-old man has received injections of his own heart stem cells after he had a major heart attack.

Researchers developed the specialized stem cells from a small piece of his heart tissue, and then injected them back into his heart to repair and re-grow healthy muscle.

This patient is the first of 16 people to undergo the procedure.

In other health news, a new study looking at Medicare patients who suffered cardiac arrests shows the odds of anyone surviving such an attack are slim. That’s even for those who make it to the hospital.

According to the study, only about 18% of cardiac arrest patients who get CPR in a hospital live long enough to go home.

Researchers found that the numbers have not improved in the 13 years since they began tracking cardiac arrests in Medicare patients.