A 75-year-old Frenchman was feeding himself and chatting to his family, more than a week after becoming the first person to be fitted with an artificial heart made by French biomedical company Carmat, one of his surgeons said.
"He is awake, feeding himself and talking with his family. We are thinking of getting him up on his feet soon, probably as early as this weekend," Professor Daniel Duveau, who saw the patient on Thursday, told Le Journal du Dimanche newspaper.
A more detailed account of the patient's health would be made public on Monday, the paper wrote.
Heart-assistance devices have been used for decades as a temporary solution for patients awaiting transplants, but Carmat's bioprosthetic product is designed to replace the real heart over the long run, mimicking nature using biological materials and sensors.
It aims to extend life for patients suffering from terminal heart failure who cannot hope for a heart transplant, often because they are too old and donors too scarce.
The artificial heart, which can beat up to five years, has been successfully tested on animals but the December 18 implant in a Paris hospital was the first in a human patient.
Three more patients in France are due to be fitted with the device. The next operation is scheduled for the first weeks of January, the newspaper reported.
In this first range of clinical trials, the success of the device will be judged on whether patients survive with the implant for at least a month.
The patients selected suffer from terminal heart failure - when the sick heart can no longer pump enough blood to sustain the body - and would otherwise have only a few days or weeks to live.
Artificial hearts thus fuel huge hope amongst patients, their families, and investors. Shares in Carmat have risen more than five-fold since floating on the Paris exchange in 2010.
Duveau told the JDD that Carmat's first patient was very combative and confident with his new prosthetic heart.
"When his wife and his daughter leave him, he tells them: 'See you tomorrow!' All he wants is to enjoy life. He can't wait to get out of the intensive care unit, out of his room, and out of uncertainty."