Sudden Cardiac Death in the Young: The Molecular Autopsy and a Practical Approach to Surviving Relatives

Christopher Semsarian; Jodie Ingles; Arthur A.M. Wilde

Disclosures

Eur Heart J. 2015;36(21):1290-1296. 

In This Article

Abstract and Introduction

Abstract

The sudden death of a young, apparently fit and healthy person is amongst the most challenging scenarios in clinical medicine. Sudden cardiac death (SCD) is a devastating and tragic outcome of a number of underlying cardiovascular diseases. While coronary artery disease and acute myocardial infarction are the most common causes of SCD in older populations, genetic (inherited) cardiac disorders comprise a substantial proportion of SCD cases aged 40 years and less. This includes the primary arrhythmogenic disorders such as long QT syndromes and inherited cardiomyopathies, namely hypertrophic cardiomyopathy. In up to 30% of young SCD, no cause of death is identified at postmortem, so-called autopsy-negative or sudden arrhythmic death syndrome (SADS). Management of families following SCD begins with a concerted effort to identify the cause of death in the decedent, based on either premorbid clinical details or the pathological findings at postmortem. Where no cause of death is identified, genetic testing of deoxyribonucleic acid extracted from postmortem blood (the molecular autopsy) may identify a cause of death in up to 30% of SADS cases. Irrespective of the genetic testing considerations, all families in which a sudden unexplained death has occurred require targeted and standardized clinical testing in an attempt to identify relatives who may be at-risk of having the same inherited heart disease and therefore also predisposed to an increased risk of SCD. Optimal care of SCD families therefore requires dedicated and appropriately trained staff in the setting of a specialized multidisciplinary cardiac genetic clinic.

Introduction

Sudden cardiac death (SCD) is a tragic complication of a number of cardiovascular diseases and affects all ages.[1–3] The death is often unexpected, and has a devastating impact on both the surviving family and the community. Sudden cardiac death is defined as a death occurring usually within an hour of the onset of symptoms, due to an underlying cardiac disease. The prevalence of SCD is significant, with up to 350 000 cases each year in the USA,[4] translating to ~950 deaths per day or one death every 1.5 min. Furthermore, the impact and public health burden in terms of life-years lost due to SCD in the young is greater than all individual cancers and most other leading causes of death.[5]

The incidence of SCD specifically in the young varies depending on the population studied and the methodologies used. The best estimate of the incidence of SCD in the general population aged 20–75 years is 1 in 1000 individuals that accounts for 18.5% of all deaths.[6] In the 1–40 years age group, the incidence is 1.3–8.5 per 100 000 person-years, and up to 4.5 per 100 000 per annum amongst male US military recruits.[7–11] Sudden cardiac death in children is at the lower end of incidence rates (1.3 per 100 000) while the higher incidence of SCD (8.5 per 100 000) is often amongst the older age groups closer to age 40 years, where outcomes are influenced by early coronary artery disease. Although relatively uncommon in terms of numbers, SCD of a young person is a tragedy and often perpetuated by both the sudden and unexpected nature of the event, and the victims often being apparently fit and healthy individuals with no history of symptoms or disease.

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