laboratory at Westmead Hospital.

The magnetic guidance catheter uses powerful magnets to guide a catheter through blood vessels to

precisely locate tissue which causes blockages of the heart.

Westmead is the first hospital in the southern hemisphere to use the US-developed procedure to treat adults and children.

Cardiology department head, Professor Pramesh Kovoor, said electricity normally flowed through a heart in a regular pattern that contracted the heart muscle, but when blocked caused an irregular heartbeat (arrhythmia).

``For some patients, their arrhythmia can't be improved through lifestyle changes or medication,'' he said.

``The most effective treatment for such patients is called cardiac ablation, which uses heat from radio frequency energy to destroy the malfunctioning tissue which may only be a few millimetres wide.

``Using this new technology, magnets guide a catheter along a pathway mapped by a computer.

``The surgeon is able to very precisely target the area of malfunction in the heart itself.

``The procedure not only increases accuracy and improves recovery times [and] because constant X-rays are not required, the patient is subjected to less radiation.''