Causes of sudden cardiac death according to age and sex in persons aged 1–49 years

Background: Knowledge of causes of sudden cardiac death (SCD) according to age is important in clinical decision making and to lower the risk of SCD in family members of the deceased. Objective: The purpose of this study was to report overall and sex-stratified causes of SCD according to age in persons aged 1–49 years. Methods: The study population consisted of all persons in Denmark aged 1–35 years in 2000–2009 and 36–49 years in 2007–2009, which equals 27.1 million person-years. Danish death certificates, discharge summaries, autopsy reports, and data from nationwide registries were used to identify all SCD cases. The SCD cases were divided into 5-year age groups. Results: In the 10-year study period, there were 14,294 deaths, of which 1362 (10%) were classified as SCD. Potentially inherited cardiac disease accounted for a high proportion (43%–78%) of autopsied SCD in all age groups. A significant proportion (19%–54%) of SCD was caused by sudden arrhythmic death syndrome in all age groups. Autopsy rates in both sudden unexpected death cases and SCD cases declined significantly with increasing age (74% in the youngest age group vs 35% in the oldest). Conclusion: The proportion of SCD cases that were identified with a potentially inherited cardiac disease postmortem was high in all studied age groups, while autopsy rates in sudden and unexpected death cases declined markedly with increasing age. Our findings indicate that diagnoses of inherited heart disease are likely missed in some SCD cases, along with the opportunity for treatment and prevention in surviving relatives.