Then came the terrifying news. Doctors at Loma Linda University Medical Center Children's Hospital told the Arnolds their daughter's heart was failing.
"Her case is pretty rare in that there is no left coronary artery at all," said Rick Arnold, a paramedic with the San Bernardino County Fire Department.
Since then, he and his wife have been at Paisley Mae's side.
"My crew has taken care of shifts for me and other firefighters have volunteered to work for me, so scheduling hasn't been a problem and I'm able to be here," he said.
Firefighters at Station 302 in Hesperia also began raising money for the family after learning about Paisley Mae's condition. They are having T-shirts and stickers made, along with organizing a 5K run.
"Having this burden on their shoulders is difficult enough without having to worry about every day bills and medical bills, so our hope is to just lessen that for them," said Blake Berg, a firefighter at Station 302.
In a six-hour operation on Monday, doctors implanted a device to help Paisley Mae's heart get the oxygen it needs. The device sits outside the baby's body. It will be the first of many procedures she is going to need, but her parents say she will ultimately need a new heart.
"The hope this will be a bridge to maintain her kidneys, her brain, her liver profusion until she receives a human heart," said Dr. Anees Razzouk, chairman of medical center's Department of Cardiovascular and Thoracic Surgery.
The device, known as a Berlin Heart, will hopefully buy the time Paisley Mae she desperately needs.
"She's just a very special little girl and we're both looking forward to seeing her grow up, God willing," the father said.
Anyone interested in donating to her fund can do so online at www.gofundme.com/24qipk or in person at a Wells Fargo bank branch under the Paisley Mae Arnold Medical Fund.
For updates on Paisley Mae, visit www.Facebook.com/ChangeofHeartforPaisleyMae.