Sudden arrhythmic death syndrome (SADS)

Cardiac arrest line

Sudden arrhythmic death syndrome, or SADS, is when someone dies suddenly following a cardiac arrest and no obvious cause can be found. This affects around 500 people in the UK every year. 

We know that, in many cases, this is caused by an inherited heart condition and the person’s immediate family should be referred to a specialist genetics centre for assessment.

What’s the difference between sudden cardiac death and SADS?

Sudden cardiac death (SCD) is a sudden death, usually caused by a heart condition, and can be confirmed with a post-mortem examination.

If the death cannot be explained, even after a post-mortem, and no cause can be found, this is called sudden arrhythmic death syndrome (SADS). In this case, testing family members for inherited heart conditions may confirm whether this was likely to be the cause of death.

How is SADS diagnosed?

If someone passes away following a cardiac arrest, the coroner (someone who is responsible for investigating deaths) will usually ask for a post-mortem to be carried out to find out the cause of death. This will usually happen within two to three working days. Hospital bereavement officers can offer support while this takes place and be your main point of contact.

During the post-mortem, a pathologist (a doctor trained in the study of disease) will look for conditions like coronary heart disease that may have contributed towards someone’s death. If obvious signs of death can’t be found, they may:

  • look at organ tissue
  • test for medications or drugs in the body
  • ask for an assessment by an expert heart pathologist.

The coroner will then decide on a cause of death. SADS is declared if the death is still unexplained after these tests. When this happens the coroner should recommend that family members are screened for inherited heart conditions.

How do they test for inherited heart conditions?

Immediate family (parents, siblings and children) of the person affected should be referred to an inherited heart conditions clinic, usually based at a hospital or specialist genetics centre.

During your appointment you’ll be asked about your health, family history and whether you have any symptoms. It’s helpful to bring information about any family who have passed away earlier than expected or been diagnosed with heart and circulatory diseases.

What causes SADS?

If you have a heart condition, you can experience arrhythmias (abnormal heart rhythms) which may cause a cardiac arrest.

Inherited heart conditions which may cause cardiac arrest if undetected and untreated include:

Download or order Life with Sudden Arrhythmic Death Syndrome booklet for more information.

Thanks to research, we now know that these conditions are caused by faults (or mutations) in one or more of our genes. We can sometimes detect these changes with genetic testing for family members, known as cascade testing. In some cases, this is the only way of telling if someone has an inherited heart condition.

Emotional support

If someone you love has been passed away due to SADS, this may be an extremely difficult time for you. It’s understandable to be confused about what’s happened and wondering if there were symptoms that were missed. You might also be concerned about your own health, or the health of other close family members.

Some people don’t feel ready to go to a specialist genetics centre for assessment straight away but the earlier you’re seen, the sooner a heart problem can be ruled out or diagnosed. If you have an inherited condition, you condition can be monitored and you’ll be given treatment if you need it.

Whatever you’re feeling, there is support available and it can be helpful to talk to family, friends and support services. 

Beating heartbreak caused by heart disease

We’ve made vital discoveries into tests and treatments, but more needs to be done.

We’re currently funding research into the genes and proteins that control the spread of electrical currents across the heart. That research is helping us understanding the heart rhythm disturbances that cause SADS.

With research we hope to diagnose people before it’s too late.


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