From outward appearances, Elena Sharp looks like a normal, happy 9-month-old baby.
She crawls, pulls herself up on the arm of a chair to practice standing and squeals when she spots a family cat through the window.
But the eyes radiating joy from her smiling face belie the ordeal that Ellie has been through, as well as the odds she's beaten.
Underneath her shirt is a vertical scar on her chest, a testament to the 14 hours of surgery she underwent last summer to correct a complex, congenital heart defect known as tetralogy of Fallot.
"Unfortunately, our daughter had one of the more severe versions," said her mother, Tara Sharp, 35, of Sebastopol.
In layman's terms, Ellie "was missing one valve, had a hole in her heart and did not have a pulmonary artery connecting the heart and lungs," Sharp said.
Ellie spent weeks in the intensive care unit at Lucile Packard Children's Hospital at Stanford. The first time was in February after her mother, in premature labor, was helicoptered from Santa Rosa's Sutter Medical Center to give birth.
Following exploratory surgery, doctors discovered Ellie was able to breathe on her own, but she still had only a 30 percent chance of survival. She was able to go home for a few months and get to know her parents and sister, Cece, 2.
Ellie returned to the Stanford hospital in July to undergo a marathon surgery with a team headed by Dr. Frank Hanley, known as the world's top expert for her particular heart disease.
The open heart and lung operation was successful, but Ellie will face other procedures as she gets bigger, to replace the valve and pulmonary artery.
"Miracles do happen," said her mother. "We have a lot to be thankful for — thankful that our daughter is alive and living today a mostly normal life."
"Her road is not done," said Ellie's father, Ben Sharp, 42. "The highest risk surgery was the first one, because of her size and immune system. Now, the prognosis is excellent. There are still a couple hurdles for her to jump."
Babies who have the surgery usually do well, according to the National Library of Medicine. More than 90 percent survive to adulthood and live active, healthy and productive lives.
"I have much less fear and concern," Ben Sharp said.
But a year ago, things were looking grim. Six months into the pregnancy, an ultrasound detected something wrong with the baby's heart.
It was then that Tara Sharp found tetralogy of Fallot ran in her family, on her Australian mother's side.
No one in the immediate family had been born with it since 1944.
"Almost everyone had died of it, except one aunt who had a mild version of it," she said. "When I started to research it, it was very alarming, very scary."
But advances in medicine provided hope, including precise laser surgery that can be performed on a heart the size of a walnut.
Tara Sharp's Santa Rosa physicians put her in contact with the Stanford experts to monitor the pregnancy and develop a game plan.
But she went into labor three weeks before the due date and had to undergo an emergency C-section after being airlifted to Palo Alto.