It makes a huge difference to the patient because they don't have a prolonged hospital stay

Royal Brompton Hospital spokeswoman

Until now patients have had to choose between open heart surgery, which requires weeks of recuperation, or swallowing a 1.5cm diameter camera.

Before this treatment was developed, doctors have had to look into the heart through cameras in the chest or oesophagus.

Pioneering

Mrs Wonnacott, of St Albans, Hertfordshire, underwent an operation which lasted 30 minutes and was able to talk and ask questions throughout.

She told the BBC: "In a way I don't feel I've had an operation. It felt 'pleasant' - I wasn't in pain.

Consultant cardiologist Dr Mike Mullen, now works at the Royal Brompton after working in Toronto, Canada for a year.

Dr Mike Mullen who carried out the innovative procedure

The technique, which was licensed in Europe two weeks ago, has been used in the US and Canada for six months.

It uses a device called an Intra Cardiac Echo (ICE),in which a camera is inserted into the heart so the surgeon can see exactly what he is doing.

The camera works by sending a sonic signal that bounces off the tissue of the heart and is fed back into a computer to produce an ultrasound image.

Plug

Patients receive a local anaesthetic in the groin two hours before the operation, and have a catheter inserted.

Then, the sonic imaging equipment and the probe are pushed up to the heart.

At the end of the probe is a clam-shaped plug. When it reaches the site if the problem, it can be detached by operating a spring mechanism, and it fills the hole in the heart wall.

The procedure lasts at most 40 minutes and there are rarely any side effects. Patients can usually go home the same day.

It costs half the �10,500 price of open heart surgery.

Forty years ago, just one in five babies born with a heart defect reached infancy. Now over 80% survive into adulthood.

Dr Mullen said: "The really revolutionary advance with this is its size, so we are able to get the ultrasound probe right in the heart.

"We are able to see more precisely and more accurately."

A spokeswoman for the Royal Brompton Hospital said patients undergoing the treatment are unable to feel anything because the camera is so tiny.

She added: "It makes a huge difference to the patient because they don't have a prolonged hospital stay."

The NHS also benefits because beds are freed up for other patients.