Four months ago, Jaheim Whigham's body was shutting down.

The eleven-year-old from Aurora, Illinois, had received a heart transplant four years earlier, but his body was beginning to reject it.

In a life-saving operation, cardiologists at Ann and Robert H. Lurie Children's Hospital in Chicago implanted a specially designed artificial heart.

Jaheim is one of the youngest people in the world - and the smallest ever - to receive such technology.

Doctors hope that the temporary device buys him enough time while they look for a new heart.

Miraculous: Jaheim Whigham, 11, from Aurora, Illinois, (pictured with nurse Catherine Theis) is one of the world's youngest people to undergo an artificial heart transplant after his body rejected the first heart he received in 2012

Touching: Jaheim (sitting) hugs his younger brother, Raheim, 8, as his parents Michael and Lakim look on. Jaheim was born with a congenital heart defect that made the left side of his heart unable to pump blood properly

Jaheim was born with a congenital heart defect called hypoplastic left heart syndrome.

This means that during pregnancy, the left side of the heart does not form correctly and therefore cannot pump blood to the body properly.

When he seven-years-old, Jaheim under went his first heart transplant. During a routine check-up, doctors found that his transplanted heart was failing. His body was beginning to reject the organ.

Doctors tried to treat him with medications, but they weren't working. Then, Jaheim's kidneys began to fail.

Then doctors told Jaheim's parents about a potential new option called the Syncardia.

The SynCardia temporary Total Artificial Heart (TAH-t) replaces both failing heart ventricles and the four heart valves, and restores blood flow to the body and vital organs.

Two small tubes connect to an external power supply known as a driver. Once the patient is stable, they can be switched from the external hospital driver to the Freedom portable driver which fits in a backpack and provides more mobility.

Jaheim's father Michael told Daily Mail Online: 'They told us about it around Thanksgiving. We were pushing to get it done and they did it really quickly.'

The 70 cubic-centimeter TAH-t would have been too big to fit in Jaheim's chest, so cardiologists chose to implant the the 50cc TAH-t, originally designed to fit women.

Success: The team at Lurie Children's Hospital in Chicago chose to give Jaheim (sitting, right) a SynCardia, a temporary artificial heart that replaces the heart ventricles and the four heart valves

Medical marvel: A 50 cubic-centimeter (cc) version had to be placed in Jaheim's heart instead of the traditional 70cc version which would have been too big to fit inside his chest

Smiling: Jaheim (pictured with nurse Catherine Theis) is recovering well and his father Michael said he is starting 'to look like his old self'

On December 1, Jaheim underwent the 15-hour surgery and is now one of only 40 people in the world to have this implant.

Dr Carl Backer, head of cardiovascular surgery at Lurie's Hospital, said the procedure was tricky because Jaheim's previous operations made re-entry difficult.

So far, recovery has been going well. Dr Backer says Jaheim's organs are recovering, he is now breathing on his, walking around the ICU and the small tubes from the SynCardia have been switched to a portable driver that he can wear like a backpack.

In the meantime, Jaheim is on a donor list waiting for a new heart. While the waiting time was three to seven months for his first transplant, this time he'll have to wait six to nine months.

Michael said: 'It's nice to see him back to his old self. He's not wiped out on a lot of medication, the skin has closed around where the tubes were.

'But the most important thing to him is that he gets home, he wants to go home.'

Waiting: Jaheim (pictured right with his mother Lakim) is now on a waiting list for a new heart. Doctors suspect that he will have to wait anywhere between six and nine months

And he still hasn't lost his sense of humor.

'During the press conference, I said I was going to ask him what his favorite baseball team was, and it's the St Louis Cardinals,' Dr Backer told Daily Mail Online.

'So during the conference I asked him, and he said the Chicago White Sox.

'Later he told his dad that he couldn't tell a bunch of people from Chicago that his favorite team was the Cardinals.'