This study will enroll people who are on the waiting list to receive a donor heart and who are undergoing LVAD implantation surgery. Before the surgery, participants will be randomly assigned to one of two groups. One group of participants will have MPCs injected into their heart during LVAD surgery and the other group of participants will have a control solution (placebo) injected into their heart during the surgery. A portion of heart muscle removed during the surgery will be analyzed. Participants will be monitored by study researchers and blood samples will be collected 12 hours after the LVAD surgery and at 1, 7, 21, 60, and 90 days after the surgery. After that, a medical history review, physical examination, and blood collection will occur every 60 days until a heart transplant occurs or until 12 months after the LVAD implantation, whichever comes first. Heart function testing, which will include an echocardiogram, neuronal function testing, and a 6-minute walk test, will occur 60 and 90 days after the LVAD implantation, and every 2 months thereafter until a heart transplant occurs or until 12 months after the LVAD implantation, whichever comes first.