MIAMI -- A patient is recovering in Miami after a procedure in a study that uses stem cells to heal patients' hearts.

In a new procedure, stem cells are harvested from a patient's bone marrow and then carefully separated and prepared. Six weeks later, the cells are injected into the patient's own heart during surgery.

This is part of a federally funded clinical trial that began this week at the University of Miami's Jackson Memorial Hospital.

"This is an absolutely astonishing accomplishment by our doctors and nurses at the University of Miami and Jackson Memorial Hospital," said Dr. Pascal Goldschmidt, the dean of the University of Miami Miller School of Medicine.

Rodolfo Hernandez, 56, recovered in intensive care after being the first of 45 patients to be enrolled in the study, funded by the National Institutes of Health.

"There will be three groups of 15 patients. One group will receive a placebo. One group will receive a low dose of their own … stem cells and the other group will receive a high dose," said UM cardiovascular Chief Dr. Joshua Hare

Candidates for this trial are patients who need coronary bypass surgery or have had a previous heart attack with damage to heart tissue affecting its ability to pump.

MRI scans will be used to measure whether study participants demonstrate improvement in heart function over 18 months.

"The MRI images will allow us to look very specifically to see whether or not we've regrown new heart muscle or not," Hare said.

This is one of three studies being launched this year looking at different ways adult stem cells might be used to regenerate the human heart.