‘Sudden Adult Death Syndrome’: Meaning, Cause, And Symptoms

Until last week, I’d never heard of sudden arrhythmic death syndrome (SADS), sometimes called sudden adult death syndrome.

But the NHS suggests it’s the most common cause of death of under-35s in the UK. It’s believed to affect about 500 people annually in England, Scotland, Wales, and Northern Ireland.

The fatal condition leads to an “unexpected” and “sudden” death.

Here, HuffPost UK spoke to Dr Dominic Greenyer, private GP at The Health Suite, about what SADS is, why it might happen, and some possible warning signs.

Despite its (less accurate, Dr Greenyer said) nickname, SADS is not confined to adults. It can affect children and young people too, the doctor explained.

The term is used when “someone dies suddenly and unexpectedly following a cardiac arrest, but a detailed post-mortem and toxicology investigation cannot identify a clear cause”.

“The heart may appear structurally normal, which can make these deaths particularly difficult for families to understand,” he added.

Dr Greenyer told us that the problem can lie in the electrical action of the heart, rather than a structural issue (like a blood clot during a heart attack).

“An abnormal electrical rhythm can cause the heart to beat dangerously fast or erratically, preventing it from pumping blood effectively and resulting in cardiac arrest,” he said.

Genes may be a factor here, too.

“Sometimes, [SADS] is linked to an undiagnosed inherited condition, such as long QT syndrome, Brugada syndrome or catecholaminergic polymorphic ventricular tachycardia, known as CPVT. These conditions can be very difficult to detect because a person may look healthy, exercise regularly and have no known heart disease,” he shared.

“The most important risk factor is a family history of sudden, unexplained death, particularly at a young age. People should also seek medical advice if a close relative has been diagnosed with an inherited heart rhythm disorder or cardiomyopathy.”

The NHS writes that “fatal arrhythmia may be the first presentation” of the condition. In other words, tragically, it might prove deadly before it shows any other signs.

But Dr Greenyer said there are some symptoms that you should get checked out if you experience them.

“Possible warning signs can include unexplained fainting, especially during exercise or emotional stress; recurrent palpitations; unusual dizziness or seizure-like episodes with no clear explanation,” he said, though the GP stressed that “most people experiencing occasional palpitations or dizziness will not have a dangerous inherited condition”.

Additionally, if you faint during exercise, develop chest pain or severe breathlessness while you’re active, or you have palpitations accompanied by fainting, you should be medically assessed by a doctor who can work out whether further scans and tests are needed.

“It is also important not to create the impression that exercise itself causes SADS,” said Dr Greenyer. “Regular physical activity is overwhelmingly beneficial for the heart. In a small number of people with an undiagnosed electrical condition, intense exercise or stress may act as a trigger, but the underlying condition is the real risk.”

People whose family members have died from SADS may be offered specialist cardiac and genetic assessment, which allows them to receive monitoring and treatment if needed, he ended.

“SADS is frightening precisely because it can affect someone who appears fit and well. However, awareness of family history and taking unexplained symptoms seriously can help doctors identify some of those at increased risk before a catastrophic event occurs.”