The majority of the approximately 100,000 sudden cardiac deaths each year in the UK are associated with coronary heart disease, but most sudden deaths in those under 30 years of age are caused by inherited cardiomyopathies and arrhythmias. In those aged 16–64 years, a coroner's post mortem examination is unable to identify a structural cardiac abnormality in 4·0%. The cause of death is therefore uncertain. These deaths are termed ‘sudden arrhythmic death syndrome’ or ‘sudden unexpected death syndrome’
