A 40-year-old father has become the first person in the UK to receive a total artificial heart that will enable him to go home.
Matthew Green had been critically ill, suffering from end-stage failure of both chambers of his heart.
But today he was preparing to return home after undergoing the ground-breaking surgery at Papworth Hospital, near Cambridge.
Doctors at the hospital have previously implanted a total artificial heart but this is the first time a patient has been well enough to leave hospital and go home.
The operation - which has also been completed successfully in the United States and parts of Europe - could help cut transplant waiting times in the future.
Mr Green said: "Two years ago I was cycling nine miles to work and nine miles back every day but by the time I was admitted to hospital I was struggling to walk even a few yards.
"I am really excited about going home and just being able to do the everyday things that I haven't been able to do for such a long time such as playing in the garden with my son and cooking a meal for my family.
"I want to thank all the wonderful staff at Papworth Hospital who have been looking after me and who have made it possible for me to return home to my family."
During a six-hour operation last month, surgeons replaced Mr Green's damaged heart with the device which will serve the role of both ventricles and heart valves.
It provides a blood flow of up to 9.5 litres, eliminating the symptoms and effects of severe heart failure.
The artificial heart will be powered by a "freedom portable driver", worn like a backpack or shoulder bag.
The transplant team at Papworth, led by Steven Tsui, consultant cardiothoracic surgeon and director of the transplant service, underwent training in Paris and was assisted by Latif Arusoglu, an expert total artificial heart surgeon from Bad Oeynhausen, Germany.
Mr Green suffered from arrhythmogenic right ventricular cardiomyopathia, a heart muscle disease which results in arrhythmia, heart failure and sudden death.
Mr Tsui said: "At any point in time there may be as many as 30 people waiting for a heart transplant on our waiting list at Papworth, with one third waiting over a year.
"Matthew's condition was deteriorating rapidly and we discussed with him the possibility of receiving this device, because without it he may not have survived the wait until a suitable donor heart could be found for him.
"The operation went extremely well and Matthew has made an excellent recovery. I expect him to go home very soon, being able to do a lot more than before the operation with a vastly improved quality of life, until we can find a suitable donor heart for him to have a heart transplant."
Mr Green received a SynCardia total artificial heart.
Papworth Hospital is the only centre in the UK currently allowed to implant this type of device.
In November 1986, a patient received a Jarvik-7 artificial heart and was supported for two days before undergoing a heart transplant.
Professor Peter Weissberg, medical director at the British Heart Foundation, said: "For some patients with severe heart failure transplantation is their only hope of long-term survival, but donor hearts are not always available.
"Previous versions of the mechanical heart have supported only the left side of the heart - the side that does most of the work - but the total mechanical heart replaces both sides and so can be used for anyone with severe heart failure.
"Patients with mechanical hearts must remain permanently linked to a power supply via tubes that pass through the skin, which is a potential source of infection.
"With this artificial heart, the power supply is small enough to fit in a shoulder bag so patients can walk around and go home."
Mr Green said he was looking forward to returning to his home in London with his son Dylan, five, and wife Gill.
He said: "Dylan's glad he's got his dad back."
In the long term he hopes to return to his job as a research scientist for a pharmaceutical company.
He said: "My movement will still be limited but at least I can return home to be with my family. That means the world to me."
Mr Tsui said that although implants had been carried out in the past, patients were until now hospital-bound.
The creation of the portable device last year made it possible for patients to return home.
An alarm on Mr Green's portable driver sounded several times as he was interviewed by journalists.
"It doesn't like it when I get nervous," he said.
He added: "It's an enormous relief. My background as a research scientist meant I could understand how it worked and perhaps made me less nervous.
"But it's a miraculous bit of technology and it's given me my life back.
"I can't stress enough how important this development could be for people like me. The freedom to be at home and live something close to an ordinary life is important and will help with my recovery in the long-term."
Mr Tsui said that the device cost £100,000 to install and about £20,000 a year to maintain. Because of the size of the replacement heart, it can only be fitted on people with large heart cavities.
He said: "We have not fitted artificial hearts frequently in the past as the patient would have to stay in hospital and that limited its usefulness.
"Now the portable console allows patients to return home so it makes it a much more viable option.
"It would not be possible on all people but, when suitable, it is a medium-term solution which buys us time when looking for a transplant.
"We're delighted this has been a success and we are delighted Matthew and his family will be able to return to something close to normality."