Adult "cot death" may explain mystery fatalities

18:04 28 March 03 NewScientist.com news service

A significant number of people could be dying from an adult version of "cot death", suggests a new study.

At least 3500 apparently healthy people collapse and die every year from unexplained causes in England alone, researchers have found. And in about 150 of these mystery deaths no cause can be identified, despite a full post-mortem examination.

Tim Bowker, associate medical director of the British Heart Foundation and a consultant cardiologist, led the study and says anecdotal reports of this type of death had baffled doctors for many years.

The researchers suggest that some of the deaths may occur due to electrical or metabolic abnormalities in the heart. However, this problem can only be identified in a living patient.

But the study shows the mystery deaths are a "real entity", Bowker told New Scientist. "And until one gives it a proper label, it is very difficult to take the science forward," he says.

Life saver

He thinks the deaths should be classed as the adult equivalent of sudden infant death syndrome (SIDS), and called sudden adult death syndrome, or SADS. This would lead to more information being collated and help find a "common thread" between cases, he says.

After cot death was officially recognised as SIDS, the number of deaths was cut by 70 per cent within a decade.

Bowker and his colleagues at the University of London asked coroners to look out for mystery deaths over a four month period, and send post-mortem reports and tissue samples. They specifically looked at white Caucasians aged 16 to 64, with no medical history of cardiac disease.

The team found that 80 per cent of the almost 700 unexpected deaths reported could be attributed to underlying coronary disease. A further proportion could be ascribed to some other kind of cardiac disease. But in about four per cent of cases no cause could be found.


Chaotic rhythms

These inexplicable deaths may be due to various causes, Bowker says: "Clearly the heart has stopped, but the structure is normal, so the first thing one should think about is electrical problems."

The beating of the heart is co-ordinated by electrical impulses generated by the flow of ions into and out of its tissues. In some conditions, problems with this electrical circuitry can mean the heart beats in an unusual pattern. "This may lead to chaotic rhythms in the heart, and so it stops," Bowker says.

But there may be other factors, unrelated to the heart, underlying this kind of mystery death. For example, the control of breathing might be lost.

Journal reference: Quarterly Journal of Medicine (vol 96, p 269)