Australian researchers have successfully transplanted and reanimated a dead heart in a world-first surgery dubbed "the biggest breakthrough in a decade".

For the first time, patients have received a successful transplant from hearts that had stopped beating for 20 minutes before being resuscitated and implanted.

The groundbreaking operations were carried out at St Vincents Hospital in Sydney.

One patient, Michelle Gribilar, said she "felt 40 again" after the procedure.

The 57-year-old Sydney woman said prior to the operation, she had not been able to walk 100 metres without trouble.

Now she walks 3km and climbs 100-120 stairs every day.

"I'm a different person altogether," she said.

In the procedure, the heart is brought back to life and placed in a machine before being injected with a ground-breaking preservation solution developed by the Victor Chang Cardiac Research Institute and St Vincent's Hospital.

The heart is preserved in a special device, the ex vivo organ care system. (Supplied)

The solution reduces the amount of damage to the donor heart, makes it more resilient to transplantation, improves heart function once it starts beating again, and limits damage taken from a lack of oxygen.

Surgeon Kumud Dhital said after the heart had been properly preserved, it only needed "volume" moving through it to restart its movement.

"Sometimes we have to kick-start it with a little electric shock," he said.

The solution took 12 years to perfect.

It is believed the new breakthrough will save the lives of 30 percent more heart transplant patients.

Until now, donor hearts have been exclusively retrieved from brain-dead patients whose hearts are still beating.

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