By Bo Gregers Winkel and Jacob Tfelt-Hansen
Until now, knowledge on sudden cardiac death in children (1–18 years of age) has been sparse. Due to small studies, crude numbers have been low and as such difficult to interpret on. Hence, deaths in children have often been pooled together with adolescent deaths to describe the burden of sudden cardiac death in the young (below age 35–40 years). Therefore, knowledge on the incidence of sudden cardiac death in children, the causes of death and symptoms prior to death are sparse.
In recent years, our understanding of the mechanisms of sudden cardiac death on a molecular/genetic level has greatly expanded. Not only the primary arrhythmogenic cardiac diseases like Long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia are better understood, but also cardiomyopathies are linked with many genes known to cause or modify phenotypic traits. Hence, many cardiac diseases known to cause sudden cardiac death may be inherited. Our general understanding depicts that the younger the age of phenotypic onset of cardiac disease, the higher the possibility that the disease is inherited meaning that family members potentially are at risk of sudden cardiac death too.
Knowing the burden and the causes of sudden cardiac death in children is the key in optimising the prevention of these deaths in the future. Hence, we took on the course of retrospectively describing sudden cardiac death in children (1–18 years) nationwide in Denmark in a seven-year period (2000–2006).1
In total, there were 87 sudden cardiac deaths in children during the period studied (7.78 million person-years). By including all deaths, the reported incidence rate of sudden cardiac death in children (1.1 per 100.000 person-years) stands as a very reliable figure. About 6% of all child deaths were sudden cardiac death, and most sudden unexpected deaths were in fact sudden cardiac death. Male deaths accounted for two thirds of all sudden cardiac deaths in children just like in older populations. Strikingly, 45% of children experienced antecedent symptoms prior to sudden cardiac death (days, months or years). Most common antecedent symptoms were seizure/syncope, chest/arm/stomach pain, and dyspnoea. Combining with prodromal symptoms (hours before death), a total of 59% of sudden cardiac deaths experienced symptoms prior to death.
Sudden cardiac deaths in children most often had a blank autopsy (29%), depicting the possibility of a primary arrhythmogenic cardiac disease. The most abundant structural heart disease was myocarditis (9%). Adding all the potential familial causes of sudden cardiac death in children a total of 49% could have an inherited trait.
Sudden cardiac death in children is a rare occurring event, but extremely devastating when it strikes. An autopsy should be performed in all cases of sudden unexpected death in which the deceased was not known with congenital heart disease prior to death. This will help the subsequent familial cascade screening to elucidate and treat potential inherited cardiac diseases in first degree family members. About half of families experiencing a child sudden cardiac death may have an inherited cardiac disease running in the family. Attention on cardiac symptoms is pivotal, as more than half of children suffering from sudden cardiac death did in fact experience symptoms prior to death. A standard examination of a child with cardiac symptoms should as a minimum include a thorough history taking including a family history, a physical examination, and an ECG.
References
1. Winkel BG, Risgaard B, Sadjadieh G, Bundgaard H, Haunsø S, Tfelt-Hansen J. Sudden cardiac death in children (1-18 years): symptoms and causes of death in a nationwide setting. Eur Heart J. Online first, Dec 15, 2013. PMID: 24344190
Bo Gregers Winkel and Jacob Tfelt-Hansen are with the Department of Cardiology, Rigshospitalet and Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark