The biggest thing is getting used to not having a heartbeat - I have a whirring sound

Robert Tools

He went on closed circuit television to explain why he took the step and describe how he felt.

It may have given him a lease of life of only a couple of months, but Mr Tools had no regrets.

Take any chance

For Mr Tools, the whirring sound of the device in his chest has taken some getting used to but the main thing is being alive.

"I had a choice to stay home and die or come here and take a chance," said the frail-looking former schoolteacher.

I realize that death is inevitable, but I also realize that if there's an opportunity to extend it, you take it

Robert Tools

"I decided to come here and take a chance. I asked for it because I knew I had no more chances to survive."

It has been a long haul for the man with the new heart.

A diabetes sufferer, he moved to Kentucky from Colorado five years ago in the hope of getting an implant.

At the time, he was so weak he could barely cross the street.

Doctors told him he would have 30 days at most with the new heart but he has proved them wrong.

He cannot return home just yet as he has to gain nine kg (20 lb) in weight as well as undergo physiotherapy and get fully used to his mechanical heart.

No more tubes

The AbioCor artificial heart, a titanium and plastic device, is self-contained, with internal and external batteries.

No wires or tubes protrude through the skin, which reduces the chance of infection.

Instead, Mr Tools wears battery packs which hang from his shoulders and power the device inside his body.

The artificial heart is the size of a softball

The chairman of the Massachusetts company that created AbioCor, David Lederman of Abiomed Inc., says Mr Tools' progress is encouraging.

"It is too early to claim success, but we are today more confident than ever that we will succeed," he said.

Four other patients are now also due to receive the devices.