Microwaves are new heart therapy
 17  May 2004

El Microwaving the heart may soon become a routine treatment for heart rhythm disorders, according to Australian researchers.
The microwave device cooks abnormal areas of the heart to 55C to block abnormal rhythms from being conducted.

The University of Technology team, Sydney, says this technique is safer and more accurate than other methods used to destroy tissue.

Their research is published in the Chemistry & Industry Magazine.

In the UK, heart rhythm disorders are commonly treated with lower frequency radio frequency ablation - a procedure used to selectively destroy areas of heart tissue, again by heating them.

But radio frequency waves produce shallow lesions and the temperatures used can be very high.

This can cause blood clots to form which can lead to complications such as stroke.

Microwaves

Microwave treatment has been used before to treat arrhythmias, but generally in combination with other surgical procedures.

WHAT ARE ARRHYTHMIAS
An arrhythmia is an irregular heart rhythm They are common and do not always need treatment A fast heart rate is often due to an extra electrical connection between the chambers of the heart Ablation destroys the extra electrical connection

Mr Hank Chui and his team hope microwave therapy could soon be used as a stand-alone treatment.

Microwaves produce deeper lesions than radio frequency waves and are easier to control and pinpoint for maximum effectiveness, they explain.

"This is exactly the same as the way a microwave oven heats meat...the difference is that the microwave exposure area is controlled much more strictly and localised heating is ensured and monitored," said Mr Chui.

He thinks microwave therapy will become as routine as radiofrequency ablation.

"Microwaves could be made available to a wider spectrum of patients instead of only
the physically fit who can endure open heart surgery," he said.

Wider use

His team are to test two new high-performance microwave devices, which have already proved successful in sheep.

Microwaves could be made available to a wider spectrum of patients instead of only the physically fit who can endure open heart surgery

Mr Hank Chui, an engineer at the University of Technology, Sydney

Prof Martin Cowie, professor of cardiology at the National Heart and Lung Institute at Imperial College London, also thought microwave therapy might become more commonly used to treat heart arrhythmias.

"It would seem a logical thing to try.

"They used to use direct heating but that's very difficult to control - the burns were too large, too deep. They went to radio frequency which is better and it is possible that microwave would be even better still," he said.

Professor Cowie thought it would be relatively easy for technicians to switch to the new procedure.

But Dr Tim Bowker, Associate Medical Director of the British Heart Foundation, said: "Various types of high intensity energy have been tried for treatment of abnormal heart rhythms, without the need for open heart surgery.

"Electrical energy is most often used in humans, and, unless future research suggests otherwise, there is no sign that microwave energy is about to replace this method."