Injecting pure alcohol into the walls of the heart brings the attack on and relieves symptoms of a form of hypertrophic cardiomyopathy.

The disease is the most common form of sudden death among young athletes and affects approximately one person in every 500 in the general population.

The new treatment offers an easy way to treat hypertrophic obstructive cardiomyopathy, which would usually require open-heart surgery.

The condition causes heart tissue to become thicker and stiffer, and this in turn causes an obstruction to blood flow.

People who have it experience fainting, chest pain and shortness of breath to the point where many cannot walk at a normal pace or climb stairs.

Improved conditions

The treatment, which was developed by Dr Ulrich Sigwart at London's Royal Brompton Hospital, is now being used by more than a dozen specialist centres worldwide.

The heart becomes enlarged

One US centre, the Baylor College of Medicine in Massachusetts, published its results for the procedure in the American Heart Association journal Circulation.

They found that all patients treated this way showed some improvement and concluded that a third of all sufferers could benefit from the treatment.

Dr William Spencer, who led the Baylor study, said: "It is not a procedure that is to be undertaken lightly because it has its hazards. Proper training and experience are necessary."

Ethanol - pure alcohol - is injected into the ventricular septum, the wall that separates the two chambers of the heart known as the atrium and the ventricle.

Toxic reaction

In patients with hypertrophic obstructive cardiomyopathy the septum is abnormally overgrown - hypertrophied - and obstructs the blood flow from the left ventricle, the main pumping chamber, to the aorta and the body.

Pure ethanol is toxic to the heart muscle and so injecting it into the heart causes a major heart attack, Dr Spencer said.

This produces scar tissue, which shrinks the obstruction, allowing blood to flow through normally once again.

During the procedure, temporary pacemakers are inserted to keep the heart beating properly.

Amazing results

The doctors reported that six months to a year after the treatment, the obstruction appeared to have been cut away with a knife.

"It is phenomenal," said Dr Spencer. "All these people are so much better."

The study looked at the treatment of 33 patients with an average age of 52, all of whom were being treated with drugs.

All patients reported improvement, although seven needed to continue on medication.

After six months five were completely without symptoms and 11 required a permanent pacemaker.