Atrial fibrillation is the most common heart rhythm disorder, affecting around half a million people in Britain alone each year. It is caused by abnormal rapid firing in the upper chambers of the heart which sends electrical signals to make the heart beat at an irregular pace.

While some patients have no symptoms, for others, it can be very alarming and cause palpitations, lethargy, breathlessness and even chest pain.

However, in the majority of cases, it is not in itself life-threatening.

Some experts claim a third of new cases are caused by alcohol, rising to two-thirds among the under-65s.

Others suggest it is responsible for between 5 and 10 percent of new cases of the condition.

Atrial fibrillation is also responsible for 20 percent of strokes, and 1 percent of the U.K.'s NHS budget is spent treating the complications, which include heart failure. It is one of the fastest growing areas in cardiac medicine, with demand for treatment increasing by 50 percent a year.

The reason why patients develop atrial fibrillation with time is unknown. However, it is more common among the over-60s and those who have valve or structural heart problems or high blood pressure.

Women are slightly more likely to develop the condition than men, but this is only because they live longer.

Dr Anthony Chow, a heart rhythm specialist at The Heart Hospital, University College London, says: "It can be triggered by binge-drinking. However, there are many other triggers, including acute illness, increasing age, existing heart conditions and aggressive sporting activity.

"It may be a one-off episode and not a concern, but if it is a recurrent problem then the structure of the heart starts to change and a large number of patients may get longer and longer episodes of atrial fibrillation -- until at some point the heart doesn't stop fibrillating at all."

Atrial fibrillation is difficult to treat. A cocktail of drugs is usually prescribed at first.

If this doesn't keep the condition under control then a cardioversion, where an electrical impulse is applied to the chest wall under a general anaesthetic, jolts the heart back into a normal pattern. However, while this immediately corrects the problem there is a 50-50 chance the condition will return within a year.

A treatment which is becoming increasingly popular is catheter ablation. This uses high-frequency radiowaves to cut the irregular electronic circuit in the heart. Tony Blair received this treatment when his heart condition, atrial flutter -- a more simple rhythm problem and different from atrial fibrillation -- returned in 2004.

Dr Chow says: "Catheter ablation for atrial fibrillation is a highly complex procedure and is done by relatively few specialists. "It can cure the problem in 80 to 90 percent of cases of intermittent fibrillation and the risks are low. It is not suitable for everyone, but is a good option in cases of recurrent symptomatic fibrillation where medication has not worked."

Trudie Lobban, founder and chief executive officer of the Atrial Fibrillation Association, says: "This treatment can restore patients to full active life with no medication. If you treat these patients, it would ... prevent deaths from stroke."

For John Jarvie, 57, from Southwest London, this pioneering surgery has transformed his life. John was just 42 when he first started having atrial fibrillation attacks.

He was healthy -- he had never been into hospital -- didn't drink heavily, smoke or suffer from stress.

"It started off on a very small scale. It was in the early hours of the morning -- about 4 a.m. -- and I woke up and my heart was missing beats. It felt like it was a machine gun firing.

"It is a very noticeable and strange sensation -- you feel a clunk in the heart and the shock of it makes you catch your breath. It lasted only a few minutes but I was petrified." Over the next 14 years, the atrial fibrillation episodes became more frequent until it was almost a permanent condition. His heart would be fibrillating for three weeks at a time, the condition would go away for a week and then start again.

Although he learned to live with the condition and continued working, it was uncomfortable.

Prescription drugs failed to keep it under control, so his doctor sent John to a specialist at Bart's Hospital in London -- one of the U.K.'s leading cardiac centers. Doctors there told him that by undergoing catheter ablation he had an 85 percent chance of curing the condition.

Sedated and semi-conscious, John underwent the procedure where up to five catheters are fed through the neck, collarbone and groin to the heart and with electronic frequencies seek out, then ablate the abnormal tissue. "It's been a year since the surgery and it has been fantastic. I take no more drugs and my life has been transformed," he says.

Source: Mail on Sunday; London (UK). Provided by ProQuest Information and Learning. Powered by Yellowbrix.

Get expert advice on atrial fibrillation.

Learn more about atrial fibrillation.

From flirting to dating to marriage ... Our Relationships & Love newsletter has the best advice for your relationship.