Epidemiology of SCD

SCD is defined as death due to natural causes within an hour of the onset of symptoms, in
the absence of any other cause, and assumed or proven to have a cardiac cause.2,3 Preexisting
heart disease may have been known to be present but the time and mode of death
are unexpected. The death may be witnessed or not witnessed.

There are three sources of information on the incidence of SCD and its underlying causes :

• death certificate and death register data
• post-mortem studies, and
• cardiac arrest registries.

Death certificate data is collected routinely and has the potential to provide information on
trends over time and to facilitate international comparisons. Analysis of post-mortem results
can provide more detailed information on the underlying pathology. Cardiac arrest registries
provide information on the circumstances of the collapse and the underlying heart rhythm,
on the emergency response and on outcomes.