The mystery connected with why people die from sudden cardiac arrest during sleep has been solved by scientists at The University of Manchester.

The pioneering research, using detailed computer models, could help save lives through preventative treatment of those most at risk from a form of heart rhythm disorder called sick sinus syndrome.

This occurs when the activity of the heart's pacemaker, the sinoatrial node, is impaired. Up to now, no-one has been able to work out why this happens.

But groundbreaking research by Professor Henggui Zhang at The University of Manchester shows how gene mutation and activity of the nervous system can combine to seriously disrupt the heart's normal rhythm.

This research means it would be possible to identify those most at risk of suffering sudden cardiac death, which can affect people of any age but particularly the healthy elderly and well-trained athletes.

It could then be possible to control the risk by using drugs or a pacemaker.

"Previously, we did not know why some people with sick sinus syndrome would die suddenly, but now we do know why risk can increase at night during sleep. Our findings may be an important step towards ways of preventing this," Zhang said.

The research, carried out with scientists from The University of Bristol, has been published in the leading journal Circulation Research.