Sudden Cardiac Arrest
Non-Genetic Cause
There are a number of conditions that can lead to sudden cardiac arrest, that are not directly caused by a known genetic condition.
Coronary artery disease (CAD)
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CAD is caused by narrowing and hardening of the arteries around the heart.
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The narrowing is caused by a build up of fats, cholesterol and other factors and it develops over many years.
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Unfortunately, coronary artery disease is very common.
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The chance of developing coronary disease increases in all people as we age.
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The chance of developing coronary disease can also increase in an individual through risk factors such as high blood pressure, high cholesterol levels, smoking, high fat diet, low activity, depression, among others.
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If the coronary disease gets worse over time, it can lead to a heart attack, which in turn can lead to a cardiac arrest.
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Most people who experience a heart attack after the age of 60 years do not have a genetic condition.
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If coronary disease is diagnosed in younger people, a genetic cause (like familial hypercholesterolaemia) may be suspected.
Spontaneous coronary artery dissection
(SCAD)
Occurs when there is a tear in one of the layers that make up the coronary arteries. This can reduce blood flow to the heart, which in turn can cause a cardiac arrest.
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Some cases of SCAD occur in people who have a rare genetic syndrome, such as Ehlers Danlos, Loeys Deitz, or Marfan Syndrome.
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However, most people who experience SCAD do not have a recognisable genetic syndrome, nor do they have any family history of SCAD.
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The underlying cause for most cases of SCAD is largely unknown.
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More research is needed to better understand why SCAD happens.
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Valve Disease
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The heart contains four valves that ensure the blood travels in the right direction.
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These include the aortic valve, the mitral valve, the tricuspid valve and the pulmonary valve.
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When heart valves don’t work properly, they can be narrow or leak, this leads to extra strain on the heart.
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Over time, this can lead to the development of arrhythmias and increases the risk of sudden cardiac arrest.