Costco Wholesale pledged to donate $10 million to help Children's Hospital Los Angeles better care for heart patients from infancy -- and sometimes even before that -- to adulthood in what the hospital called its largest single corporate gift.

The donation will benefit the areas of the hospital most in need, including the open-heart surgery institute where doctors have performed surgeries on babies before birth. Children's Hospital Los Angeles has performed heart surgery on a 25-week old baby while in utero.

Doctors in the video said the baby's heart was the size of a walnut at the time.

Costco's donation was so significant that the hospital, founded in 1901, planned to rename the second floor the "Costco Wholesale Floor." The second floor at Children's Hospital Los Angeles is home to the Heart Institute where pediatric heart surgeries take place.

Eileen Garrido, a 15-year-old heart patient at Children's Hospital Los Angeles, has been on that floor before. She was just one month old when she underwent open-heart surgery at the hospital for a congenital heart condition.

In June, she had a third successful heart surgery, and is expected to speak during a ceremony Wednesday announcing the donation.

"I want to make sure every child has a healthy beating heart," Garrido said in a news release.