Hopes of a breakthrough in the treatment of asthma sufferers were raised yesterday when Scottish scientists revealed that inserting mini heaters into the lungs helps cut asthma attacks.

Hopes of a breakthrough in the treatment of asthma sufferers were raised yesterday when Scottish scientists revealed that inserting mini heaters into the lungs helps cut asthma attacks.

A trial led by experts at Glasgow University found feeding special heating devices into the chest significantly improved the health of asthma sufferers.

Researchers said the unusual procedure, called bronchial thermoplasty, could offer a new alternative to people with severe asthma who do not respond well to existing treatments.

Glasgow University's professor of respiratory medicine Neil Thomson, author of the study, said: "There is no doubt that some patients clearly have felt a considerable benefit in their asthma control and what they are able to do, following this therapy."

Asthma is one of the most common medical conditions, affecting more than five million people worldwide, and Scotland has among the highest rates of the disease in the world.

In sufferers, the tubes that carry air in and out of the lungs are particularly sensitive and easily become swollen. The condition is usually treated with inhalers, which deliver medicine directly to the lungs, causing the muscles in the airways to relax and open up.

However, for some patients these and a range of other medications fail to keep their asthma under control.

Severe asthma patients have more smooth muscle around their airways than non-asthma sufferers. This is the muscle which narrows the air passages when it contracts.

Bronchial thermoplasty, which has been in development for 10 years, delivers thermal energy to the airway walls and reduces the amount of smooth muscle.

Patients are put under light sedation and a thin, flexible tube is inserted through the nose or mouth into the airways. At the end a basket expands toward the airway walls and emits the heat.

Patients receive the treatment over three separate sessions, each covering a different area of the lung and each lasting less than an hour.

The results of trials suggest the benefits continue for at least a year.

Professor Thomson said: "What was interesting in this study was the benefits were still present a very long time after treatment. There was no evidence of the benefits lessening as the year went on."

More than 112 patients in four countries took part in the Glasgow-led trial, the largest to date.

Half of the patients received bronchial thermoplasty on top of their usual treatment regime, and all were monitored.

The scientists found the thermoplasty patients experienced around 10 fewer asthma attacks in the year, were free of their asthma symptoms an average of 86 additional days and required significantly less rescue medication.

Asthma UK welcomed the latest trial results and called for more research into the long-term effects of the treatment.