Sudden cardiac death: six possible causes

Sudden cardiac arrest is most often caused by coronary heart disease.Sudden cardiac arrest is most often caused by coronary heart disease.

It happens within a few seconds, usually without notice. A diseased heart is often the cause. Why sudden cardiac death occurs and how you can protect yourself.

Sudden cardiac death, also known as instantaneous cardiac death, is the most common cause of death outside of hospitals. Over 65,000 people die from it in Germany every year . The immediate trigger is almost always a life-threatening cardiac arrhythmia as a result of heart disease. It leads to cardiac arrest within a few minutes.

Older men belong to the risk group

The frequency of sudden cardiac death clearly depends on age and gender: men over 65 are particularly affected. The death rate for men over 79 is twice as high as that for women in this age group.

The likelihood of certain heart diseases causing sudden cardiac death also depends on age. “By far the most common cause in patients over 40 is coronary heart disease and the resulting heart attack, followed by heart failure , cardiomyopathies and myocarditis as well as heart valve diseases,” says Professor Thomas Voigtländer, CEO of the German Heart Foundation, on the occasion of the nationwide heart weeks.

It can also affect younger people

Although the risk of sudden cardiac arrest is higher in older people, younger people are not immune. In the under 40 age group, athletes are particularly at risk.

Suddenly and unexpectedly, they usually experience cardiac arrest without any previous symptoms. The most recent prominent example is the Danish professional footballer Christian Eriksen, who survived a cardiovascular arrest during the European Football Championship in 2021 thanks to immediate resuscitation.

The most common causes of sudden cardiac arrest before the age of 40 are congenital heart muscle disease, some forms of genetic heart disease, myocarditis and drug addiction.

Sometimes there are warning signs

In most cases, sudden cardiac death occurs suddenly and unexpectedly. It is not uncommon for it to attack those affected while they are sleeping. However, sometimes there are warning signs in advance that allow patients to seek help in a timely manner.

The majority of patients who have survived a sudden cardiac arrest after successful resuscitation report heart palpitations, shortness of breath, chest pain, attacks of dizziness, brief loss of consciousness or blackening of the eyes.
The causes of sudden cardiac death can be very different. The German Heart Foundation has summarized the most common ones.

Cause number 1: Coronary heart disease (CHD)

In Germany, around five million people are known to have CHD. As a result, circulatory problems in the heart and calcification of the coronary arteries (arteriosclerosis) often occur. They are one of the main causes of sudden cardiac death.

The tricky thing about CHD is that, unnoticed by the patient for years, plaques made of calcium, connective tissue and cholesterol can develop on the walls of the coronary arteries, which only become noticeable when the narrowing of the arteries has reached a critical threshold of 70 to 80 percent and there is a reduced supply of oxygen and nutrients to the heart muscle.

This leads to chest pain, chest tightness (angina pectoris) or shortness of breath during physical exertion. “You should go to a clinic immediately,” warns Voigtländer. If the symptoms occur at rest and last longer than five minutes, there is a suspicion of a heart attack, which can turn into ventricular fibrillation at any moment and thus trigger cardiac arrest. Those affected should then immediately call the emergency services on 112.

  • Further information : Coronary heart disease often remains undetected for decades

Effective medications are available for the treatment of CHD against the underlying and accompanying diseases such as high blood pressure, high cholesterol and diabetes mellitus. In addition to medication, stent therapy (stent = vascular support) or bypass surgery are often used to treat vascular narrowing. Therapy requires lifestyle changes through regular exercise, a balanced diet, quitting smoking and weight control.

Cause number 2: heart failure

Sudden cardiac death often occurs with heart failure (heart failure) that has developed as a result of a heart attack, valve disease or heart muscle disease. “That’s why the early detection and treatment of these heart diseases is so important in order to prevent heart failure or delay its progression,” says Voigtländer.

In heart failure, the heart is no longer able to pump enough blood to supply the body with sufficient oxygen and nutrients. In patients with severely impaired pumping capacity of the left ventricle, the risk of sudden cardiac death is usually due to the occurrence of malignant rapid arrhythmias from the ventricle. It may therefore be advisable for them to have a cardioverter defibrillator (ICD), or “Defi” for short, implanted.

With the help of medication, usually in combination of several substances, the heart’s pumping performance often improves significantly. In addition to therapy, measures for a healthy lifestyle through regular exercise, a balanced diet and weight control are essential.

Cause No. 3: Inflammation of the heart muscle

Young and older people can be affected by inflammation of the heart muscle (myocarditis), which often involves the pericardium (perimyocarditis). They account for five percent of deaths due to sudden cardiac death.

Inflammation of the heart muscle is often caused by viruses, bacteria or fungi. An exception is autoimmune myocarditis, in which immune cells attack the heart muscle from the inside rather than from the outside.

  • Further information : What makes myocarditis so dangerous

“The ambiguous symptoms of viral myocarditis are a problem because those affected by a viral infection attribute tiredness, fatigue or shortness of breath to the infection without thinking that the heart is involved,” explains Voigtländer. “Pain behind the breastbone and a racing heart can, but by no means have to, occur.”

A study of young athletes who died due to myocarditis shows that almost all of them had previously experienced an upper respiratory tract infection. Heart specialists therefore advise athletes to always take enough care of themselves if they have an infection and to only resume training when they are completely healthy again and feel fit.

Cause #4: Heart muscle disease

Heart muscle diseases (cardiomyopathies) are present in around 15 percent of patients who die from sudden cardiac death. A distinction is made between pathological expansion of the heart muscle (dilated cardiomyopathy, short: DCM), pathological thickening (hypertrophic cardiomyopathy, short: HCM) or stiffening of the heart muscle (restrictive cardiomyopathy).

Gene mutations make it difficult to identify those at risk early. The causes are usually genetic, for example in the case of HCM and DCM. Factors such as long-standing high blood pressure, diabetes, excessive alcohol consumption or inflammation can also damage the heart muscle cells and even lead to cardiomyopathy.

“Due to the hereditary component, anyone with a history of sudden cardiac deaths in the family, especially those under the age of 40, should be alert and have this diagnosed quickly at a specialized center,” advises Voigtländer.

Cause #5: Heart valve disease

Patients with heart valve defects also have an increased risk of premature cardiac death. Mitral valve prolapse, which occurs frequently and is mostly harmless, can in rare cases be associated with cardiac arrhythmias that can be life-threatening.

It is not yet known why sudden cardiac death occurs with a mitral valve prolapse. Among other things, it is assumed that there is an interaction between tissue changes in the heart muscle and an increased tendency of the heart to develop arrhythmias.

Cause #6: Congenital heart defects

Thanks to advances in treatment, over 90 percent of patients with a congenital heart defect now reach adulthood. In Germany there are around 330,000 people.

  • Further information : What living with a heart defect means

Although they are a very heterogeneous group of patients due to the different clinical pictures, there is also an increased risk of sudden cardiac arrest. How high the individual risk is depends on the type of malfunction, which can have different effects.


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