Sudden arrhythmic death syndrome, or SADS, is an uncommon but devastating condition in which a person dies suddenly and unexpectedly, and no definitive cause is identified even after a post-mortem examination. NHS guidance sets out detailed advice on the condition, which is estimated to affect about 500 people in the UK every year.
The condition has come under renewed public attention following the death of Alex Hughes, the 38-year-old son of former Manchester United and Wales footballer Mark Hughes. Alex collapsed at his home in Cheshire on June 19, and an inquest later heard that he died from Sudden Arrhythmic Death Syndrome — sometimes referred to as Sudden Adult Death Syndrome — with the death recorded as being from natural causes. SADS is most often discussed in relation to sudden deaths among younger people and can be especially hard to detect in advance, because some inherited heart rhythm disorders produce few warning signs, or none at all. According to the NHS, some people only learn they may have an inherited arrhythmia after an ECG test or after an episode such as fainting.
There are warning symptoms that can appear in people with inherited heart conditions associated with SADS. However, having one of these symptoms does not mean a person has SADS, and some individuals with potentially serious inherited cardiac conditions may never notice any symptoms.
Symptoms and warning signs to be aware of – full list
It is important to stress that these symptoms are not, on their own, proof of SADS or an inherited heart disorder. NHS advice notes that palpitations, dizziness and similar symptoms can have many different causes, while some people with dangerous inherited conditions may appear completely well.
SADS may be connected to a number of inherited arrhythmia syndromes, including long QT syndrome, Brugada syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia and Wolff-Parkinson-White syndrome. Certain cardiomyopathies, which affect the structure or function of the heart muscle, can also increase the risk of sudden cardiac death.
Family history can play a crucial role, as many of the inherited conditions linked with SADS can be passed down through families. The NHS recommends gathering a detailed family history of unexplained sudden deaths and inherited heart conditions, and relatives may be offered specialist assessment or genetic testing if doctors suspect an inherited cause.
Anyone who has repeated palpitations, dizziness or fainting episodes should seek medical advice, especially if there is a family history of sudden unexplained death or an inherited cardiac condition. The NHS says 999 should be called immediately if someone is unresponsive, not breathing normally or appears to be in cardiac arrest. Urgent medical help is also advised when palpitations occur alongside chest pain, breathlessness or fainting.
The important point is that SADS is not a symptom that can be diagnosed from a list alone. Investigations such as an ECG and specialist cardiac assessment may be needed to identify an underlying rhythm disorder, and finding an inherited condition can allow relatives to be assessed and, where appropriate, treated to reduce the risk of serious complications.
