We’re all aware that heart disease is a major problem in the UK, and things like smoking, obesity and high blood pressure are linked with an increase risk of heart attack. But how familiar are you with sudden cardiac death?
Sudden cardiac death is an umbrella term to describe death that results from the heart stopping suddenly – known as sudden cardiac arrest, which is not the same thing as a heart attack.
A US study was recently published in the Journal Of The American Heart Association, which, for the first time ever, estimates the lifetime risk of sudden cardiac death.
The research, led by Dr Donald Lloyd-Jones and his team at Northwestern University Feinberg School of Medicine, found one in nine men and one in 30 women will die from sudden cardiac death before they reach 70.
While the study in question was carried out in the US, sudden cardiac death is a huge concern in the UK too. Here, Christopher Allen, a British Heart Foundation senior cardiac nurse (www.bhf.org.uk), explains some of the key points…
What is sudden cardiac arrest and how’s it different to a heart attack?
“A heart attack is an interruption of the blood supply to the heart muscle,” explains Allen. “When you block the blood supply to any part of the body, that tissue starts to die because it’s not getting oxygen; that’s what happens when you have a heart attack.
"But a cardiac arrest is what you need CPR for. Your heart stops beating altogether, it’s not pumping blood around the body, and without CPR you will die.”
What causes sudden cardiac arrest?
While, as Allen explains, heart attack and sudden cardiac arrest are two different things – a heart attack can sometimes lead to cardiac arrest, which is why heart attacks are a medical emergency. However, they’re not the only cause, and sudden cardiac arrest can often be the result of an inherited condition.
Muscle problems and electrical disorders
There are a number of inherited conditions linked with sudden cardiac arrest, some far rarer than others. Allen explains: “These can be either a muscle problem; due to a certain condition the heart muscle can become damaged in some way, and may become very thick or stretched, and that can lead to life threatening abnormal heart rhythms.
"There are also electrical problems. The heart works on an electrical circuit and if it doesn’t follow the prescribed pathway, or if there’s something wrong with that pathway, it can sometimes lead to cardiac arrest.”
These muscle related conditions include hypertrophic cardiomyopathy, dilated cardiomyopathy and ARVC (the condition which caused former England cricketer James Taylor to retire earlier this year), and electrical conditions include Long QT syndrome and Brugada syndrome.
Is sudden cardiac arrest always fatal?
Remember the amazing case of footballer Fabrice Ndala Muamba, who collapsed mid-game from a sudden cardiac arrest? His story showed it is possible to survive – but also that time is of the absolute essence; appropriate treatment has to be delivered urgently. This is why CPR really can be life-saving, and having access to a defibrillator can also make a significant difference to survival rates.
“Less than one in 10 people who suffer a sudden cardiac arrest in the community (ie, while not already in hospital) will survive,” says Allen. “This is why we think it’s so important that people learn how to perform CPR, and that defibrillators are adequately available in public places.”
What can I do to reduce the risk?
As mentioned, sudden cardiac death can sometimes be triggered by a heart attack.
In this sense, overall risk of sudden cardiac death can be reduced via the same steps you’d take to reduce your risk of heart disease – managing your weight, blood pressure and cholesterol, not smoking, keeping alcohol intake moderate and eating a healthy, balanced diet with plenty of fruit and veg and fish, and avoiding less healthy processed foods.
In terms of inherited conditions, it entirely depends on whether the relevant genetic mutations are passed on.
What about inherited conditions?
“Often, if a parent has one of the gene mutations, with each pregnancy there’s a 50% chance of passing it on,” says Allen.
"However, not everybody with the gene mutation will develop the condition.” Families might not always be aware they carry these genes – until tragedy strikes and a sudden cardiac death occurs, alerting doctors to check whether other family members might be at risk.
There might be symptoms which are often vague, such as palpitation, dizziness and blackouts. Allen stresses that symptoms like palpitations don’t usually mean anything serious – but you should always get them checked with your GP just in case.
“And if any family members have a sudden cardiac arrest, especially if it occurs at a young age, that should ring alarm bells,” Allen adds.
Tests can determine whether other family members have inherited the faulty genes, and if they are found to be affected sometimes procedures – including implanted defibrillators and pace makers – can help manage the condition and reduce the risk of sudden cardiac death.