Nationwide study of sudden cardiac death among children and young adults in Iceland

Abstract Introduction Sudden cardiac death (SCD) in children and young adults is a devastating event. Ischemic heart disease is the predominant cause of sudden cardiac death in older persons. Whereas among persons 1–35 years of age, SCD is more often caused by structural heart disease or purely arrhythmogenic causes. In studies on SCD in the young up to 40% of all autopsies show no cardiac abnormalities. Which raises suspicion of underlying arrhythmogenic causes. Many of these arrhythmogenic causes of SCD have an underlying genetic basis and are inherited. Purpose In Iceland, the true impact of SCD in children and young adults is unknown. The aim of this investigation is to study the incidence and causes of SCD in persons aged 1–35 years in nationwide settings. Methods This is a nationwide retrospective population-based study in Iceland. All deaths in persons aged 12–35 years in 1974–2015 and all deaths in persons aged 1–12 years 2005–2015 were included. Death certificates, autopsy reports and medical records were reviewed to confirm SCD. Medical records were also reviewed for medical history and circumstances of death. Individuals that were resuscitated after cardiac arrest but died later in hospitals were included. Individuals that fulfilled the criteria of SUDEP (sudden unexpected death in epilepsy) were excluded from the study. Results We found 73 (68% male) cases of SCD, of which 64 (88%) were autopsied. The most common find in autopsy was structurally normal heart (16%), myocarditis (16%), hypertrophic cardiomyopathy (16%) and ischemic heart disease (16%). Death occurred during daily activities in 36% of cases, sleep in 27% cases and physical activities in 19% of cases. Incidence rate was 1.4 per 100.000 in 1–35 years old in the years 2005–2015 and 1.6 per 100.000 for 12–35 years old in the years 1974–2015. Conclusion Incidence of SCD in the young in Iceland is similar as for other nations. Post-mortem diagnoses are often difficult to establish. Because of the possibility of unrecognized underlying inherited cardiac disorder it is important to consider genetic analysis as a part of the post-mortem examination. Majority of SCD in the young occurred related to normal daily activities or during sleep or at rest. This raises many questions about the connections between any underlying cause of SCD and behaviour. It is important to discuss and study further the connection between sudden unexplained death in epilepsy (SUDEP) and SCD. SUDEP is most often unwitnessed events with cases found deceased in bed. SUDEP is characterized by an absence of any identifiable cause of death post-mortem, which can suggest underlying arrhythmogenic cause. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2