Sudden cardiac death (SCD) is a rare but devastating event among children and young adults. SCD in which no obvious cause is apparent despite comprehensive toxicological and histological autopsy analysis is particularly vexing.  The role of genetic testing in unexplained SCD is studied in this prospective analysis of  Australians and New Zealanders 1 to 35 years old.  Between 2010 and 2012 a total of 490 SCDs were identified across the population of 26.7 million (1.3 per 100,000). Seventy-two percent were boys or men. The highest overall incidence was in persons aged 31-35, in whom coronary artery disease was the commonest cause, and the lowest incidence was in children aged 6-10.  Inherited cardiomyopathies were found in 16% of all cases.  Most deaths (65%) occurred either at rest or during sleep, whereas sudden death during or after exercise was relatively uncommon (15%). Following post-mortem, 40% of cases were classified as unexplained. Female sex, younger age and death at night particularly common in this sub-group.  Subsequent genetic analysis was performed in these individuals using commercial panels of 59 cardiac genes including genes for long QT and catecholamine polymorphic ventricular tachycardia. As an alternative, 72 epilepsy genes were also investigated. Among analyzed individuals, 27% were found to have a clinically relevant cardiac gene disorder considered the probable cause of death (only 6% were found to carry an epilepsy gene).

Conclusions

In young individuals with sudden cardiac death, genetic testing in addition to comprehensive post-mortem studies maybe useful in establishing a cause of death. The implicit value of such testing being screening of affected families, not population-based prevention.

Bagnall RD, Weintraub RG, Ingles J, Duflou J, Yeates L, Lam L, Davis AM, Thompson T, Connell V, Wallace J, Naylor C, Crawford J, Love DR, Hallam L, White J, Lawrence C, Lynch M, Morgan N, James P, du Sart D, Puranik R, Langlois N, Vohra J, Winship I, Atherton J, McGaughran J, Skinner JR, Semsarian C. A Prospective Study of Sudden Cardiac Death among Children and Young Adults. N Engl J Med. 2016 Jun 23;374(25):2441-52.

Authors: Hussain Contractor & James M McCabe