Image caption Sevket Gocer, right, was the first patient in the UK

A pioneering operation to improve the function of failing hearts while they are still beating has taken place in the UK for the first time.

Patients with heart failure struggle to pump blood around the body and mild exercise can leave them breathless.

Surgeons used a form of "cardiac sewing" to remove scar tissue and reduce the size of the heart so it pumps more efficiently.

The operation took place at King's College Hospital in London.

One common cause of heart failure is when the arteries which nourish the organ become blocked, leading to a heart attack. Heart muscle dies and is replaced by hard scar tissue which does not beat.

Over time, the scar tissue can stretch so chambers of the heart become larger, meaning the organ has more blood to force out with each heartbeat.

The overall effect is a weaker heart, less able to do its job, transforming simple day-to-day tasks like climbing stairs into extreme exertions.

In the operation, surgeons used a wire with anchors at both ends to pierce two sections of heart muscle. When the wire was tightened, the walls of the heart were "remodelled".

Image caption Scar tissue, in grey, is "sewn out"

The scar tissue was effectively removed and the volume of one of the chambers of the heart was reduced by a quarter.

Sevket Gocer, 58 and from Bromley in south-east London, was the first patient to be treated in the UK. His heart function is said to have "improved significantly" after the operation.

A similar procedure used to be performed by opening up the chest and stopping the heart, but it was a very risky operation and fell out of medical practice.

Surgeons hope the less invasive operation, which can be performed while the heart is still pumping, will be a better option for patients.

Mr Olaf Wendler, a professor of cardiac surgery at King's College Hospital, told the BBC: "In the technique we have now used for the first time in the UK, one does not need to stop the heart, one does not even necessarily need to place the patient on a heart-lung machine.

"It's a less traumatic and less invasive type of procedure."

He said the operation was being tested in a trial at hospitals across Europe and that the procedure could make a difference to patients' lives.

He said: "[If successful] it's bringing them on to an exercise level where they're able to look after themselves properly including going to do the shopping and having a social life."

Prof Jeremy Pearson, associate medical director at the British Heart Foundation, said: "The results of this trial will determine if this experimental procedure is safe.

"If the trial is successful, there will be further use of the technology as surgeons gain expertise in the technique. As more people are treated with this procedure, it will become fully clear whether it will have a real benefit for patients."