Doctors in Montreal have implanted an experimental heart valve into an ailing 64-year-old woman without opening her rib cage.

The woman, whose name was not released, needed a new aortic valve. But poor health from severe pulmonary fibrosis and aortic stenosis cut her lung capacity by more than half in recent years, ruling her out for regular open heart surgery.

Breathing was a chore and affected her every move, said the woman's daughter, Mary Luongo.

"It was very difficult for her to move around the house," Luongo told a news conference Tuesday. "Going to the washroom was difficult. Taking a bath was difficult. She couldn't do anything for herself."

To save her, doctors at the Montreal Heart Institute tried an experimental implantation for the first time in North America.

On Dec. 6, doctors pierced her skin, inserted a catheter through a femoral artery and pumped an expandable pig valve into her beating heart.

Within hours of the procedure, the patient was breathing on her own. Her cardiologist, Dr. Raoul Bonan, is pleased with her progress.

"For the time being, she seems to improve, and the cardiac condition shows improvement," Bonan said. "The contraction is better than what it was, more than double."

The valve's manufacturer said the technique eliminates the need for open heart surgery in a cardiac operating room, may reduce the risk of infection and could lead to quicker recovery.

The medical team said the expandable heart valve could become common for others who aren't good candidates for surgery in about five years.