Cardiac inherited disease associated with sudden cardiac death
Careful clinical evaluation of the relatives of such young sudden death victims, and genetic testing of the deceased’s DNA can reveal that about a third have familial arrhythmic syndromes, such as Long QT syndrome (LQTS); Catecholaminergic Polymorphic VT (CPVT), Brugada Syndrome (BRS), and Short QT syndrome (SQTS).
This means that every young sudden death must be investigated thoroughly, not only for the diagnosis and explanation for the next of kin, but also because other family members may be at risk. Family members, once identified, can be protected, often with very simple interventions, such as a daily beta blocker.
Although New Zealand has been a leader is such investigations, some sudden death cases in the 1 – 40 year old age group are still not being referred to CIDG. We are very concerned that these families are not receiving the clinical screening and risk assessment that they need. We are hoping to address this need by providing a service to these families so that they themselves or their G.Ps can ask for a review of the sudden death in the family and obtain an opinion from CIDG.
Sudden cardiac death is a tragic, unexpected and unpredictable event that can be attributed to a vast number of possible causes and medical conditions including cardiovascular (primary cardiac causes such as abnormal coronary arteries), metabolic, biochemical, genetic and structural heart disease, and can sometimes be multifactorial i.e. as in the case of a previously undiagnosed cardiac inherited disease. Several abbreviations to describe SCD have arisen in medical literature, such as:
SADS: Sudden Adult Death Syndrome
SIDS: Sudden Infant Death Syndrome
SUDI: Sudden Unexplained Death in Infancy
SUDY: Sudden Unexplained Death in the Young
SUDEP: Sudden Unexplained Death in Epilepsy
Sudden cardiac death (SCD) is indiscriminate and may affect all ages, genders, nationalities and ethnic groups without exception. These conditions are inherited in a manner such that there is a 50% chance of a first degree relative also carrying the at-risk gene. Sudden death most commonly occurs during sleep or during routine daily activities. Less commonly they can occur during emotional stress as well as physical exertion.
A family history of other sudden death in young people, or of recurrent seizures or blackouts can point to a familial condition. Once a diagnosis is made, steps can be taken to protect the affected people in the family to prevent other sudden deaths. Education, medications, minor surgical procedures and sometimes implantable defibrillators can be used depending on the level of risk to the family member.
If you have suffered such a tragedy in your family, we hope that this webpage will provide information and advice to assist you. CIDG is set up to help families in this position, and we can work with you, your local physicians, and the forensic or coronial service to get the information you need and help get family members investigated if it is appropriate.
It is important to note that some sudden deaths have been misdiagnosed in the past. Examples may be unexpected drowning in a strong swimmer in calm conditions, and straight road motor vehicle accident, or death due to epilepsy. Although severe epilepsy can rarely be fatal, it is also true that many cases of long QT syndrome and other cardiac rhythm conditions have been misdiagnosed as epilepsy for many years, and even after death.