Investigation of Sudden Cardiac Death (SCD) cases in New Zealand

Tragically, sudden unexpected death in otherwise healthy young people (aged 1-40 years) is a relatively common occurrence, with up to 90 such deaths in N.Z. each year.

In many cases, more than half, a cause can be found at autopsy.  Many deaths are not due to inherited conditions, and the family can be reassured that no other family members are also at risk.  However, some of these deaths are due to inherited heart conditions like hypertrophic cardiomyopathy (HCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) which can be seen on an autopsy examination.  When these are found it is vital that the family members see an expert cardiologist to make sure they do not have the condition.

In about a third of cases, no cause is found, leaving the family without an explanation for the sudden tragedy.

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.

What is Cardiac Inherited Disease Group’s (CIDG) role in investigation of sudden explained death in N.Z.?

Since our inception at 1999 CIDG has been working with families of SCD victims to try to establish a cause for these deaths.  One mother described this as there being “so much why”, her mind, and this message is echoed by nearly every family we meet. To understand ‘why’ is a very basic need for families affected by the sudden death of a young person.

When a case is referred to CIDG by the Coroner we go through the same and very specific process with each case to determine if we can add value for the sake of the family.  Typically we do not receive referrals from the Coroner for some months after the death since Pathologists must wait for toxicology and other test results to be completed before a referral can be made.

Case information including hospital and G.P records where applicable are presented to a multidisciplinary group by a lead Clinician with a Pathologist present. These case meetings occur typically twice a month.

Information about how CIDG can assist families can be found on the Coronial Services Website (link to the Coronial Services page CIDG).

Referral Process for SCD cases:

Coroners and Pathologists in New Zealand  are unfortunately are placed under a lot of pressure from families to NOT conduct post mortem examinations in young sudden death victims, since families are often not keen on this intrusion following the death of a young otherwise healthy young person.   CIDG however strongly advocate for and recommend that high quality Coronial Post mortem examinations are undertaken with preservation of small tissue samples and some DNA, since without this detailed examination a direct cause of death can be missed, leaving the rest of the family at possible risk, or not knowing if they can be cleared of risk.

Post Mortem examinations form a vital part of our investigation and understanding about the cause of sudden death in young New Zealanders. Pathologists and Coroners are very sympathetic to the opinions and wishes of the family and understand that families and loved ones do not find this process easy. There is ability for families to remain near to loved ones during the post mortem process and for DNA to be stored also allowing molecular autopsy to look for the genetic causes of these hereditary diseases.

The Ministry of Justice (MOJ; Coronial Services website has detailed information about the post mortem process and they issue a booklet to families at the time when a sudden death is being investigated that also details the process. There is also a factsheet available about the role of CIDG’s involvement (please click this link to read it).

Family Meetings

CIDG arrange for the family to come in to meet with us to discuss the sudden death and we take time to sit with the family and answer any questions related to the sudden death or the post mortem findings.  We take a thorough family history and also a thorough history of the medical history of the sudden death victim.   Through taking this history and drawing up the family tree and providing some routine non-invasive screening ECGs for the family members we can often diagnose the cause of the sudden death.

Molecular Autopsy:

Genetic testing on DNA stored at post mortem examination can also be tested to confirm the diagnosis and the results used to benefit screening in the family and rule out people with no clinical or genetic signs of the condition (this can be very reassuring to parents who have other children who may potentially be at risk).

Cases not referred at the time of Post Mortem or that do not receive a post mortem examination- we are willing to listen and to give advice.

These cases warrant a special mention since some families have never been offered any information or discussion with a qualified Clinician about the death.  They are also unlikely to have had any clinical screening or investigations performed on them.   CIDG does accept referrals from General Practitioners on behalf of families in this position since we are concerned about further risks in these families. If you think that this type of referral may be appropriate in your family please have your G.P. review our SCD information form (download this here), and write a referral on your behalf.   We will contact you and your G.P when we receive the referral to obtain further information and organise to obtain the data so that the case can be reviewed at  a clinical review meeting (we may need to obtain the Next of Kin consent to obtain documentation from the Coroner).  Alternatively you can fill in the contact details information at the bottom of this page and email us about this however it is advisable to discuss this referral with your G.P. and with the next of kin of the deceased person so that the family since their involvement would be required.

First degree family member referrals for clinical screening tests:

If you are a first degree relative (parent, child or sibling) of a sudden death victim we can arrange to see you in one of our regional clinics and book you for the relevant screening tests as appropriate for each case.

Please feel free to contact us via the contact form on this page, or via cidgadmin@adhb.govt.nz, and one of our coordinators will be in touch. Be sure to leave sufficient contact information and a succinct and clear summary of why you wish to speak with us.