Sudden cardiac death in young people is a rare but alarming occurrence. Doctors define sudden cardiac death as a death resulting from a heart-related issue that occurs within 1 hour of symptoms starting.
In many cases, the underlying heart issues are unknown, making sudden cardiac death even more traumatic for loved ones.
In most cases, sudden cardiac death in young people — that is, people under 35 years of age — is due to a genetic or congenital condition, which doctors may or may not have diagnosed before the time of death.
This article looks at some of the most common causes of sudden cardiac death in people under 35 years of age. It lists the potential symptoms to be aware of and explains how to prevent fatal complications from underlying heart diseases.

Sudden cardiac death is rare in young people, which makes estimating its frequency challenging. Researchers most often study sudden cardiac death in young athletes, as it is the
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The authors of the review note that among athletes, the groups that are most at risk include:
- males
- Black athletes
- basketball players
In the general population, estimates suggest that the rate of sudden cardiac death among people ages 18 years or younger, but excluding infants, is between
In young people, sudden cardiac death is most often genetic or congenital in nature. Acquired forms of heart disease that lead to sudden cardiac death are rare but possible.
These types of conditions affect the structure or rhythm of the heart, which places strain on the heart muscles and affects blood flow.
The most common cause of sudden cardiac death in young people is hypertrophic cardiomyopathy (HCM). HCM is a genetic heart condition that affects up to
In HCM, the muscles of the left ventricle become thickened and enlarged, which can result in a reduced left ventricle volume and impaired activity of the aortic valve. These effects can make it more difficult for the heart to pump blood to the rest of the body, place strain on the heart and lungs, and disrupt typical heart rhythms.
In most cases, HCM is benign, and many people may not even experience symptoms. In some cases, though, heart complications can develop. Sudden cardiac death may occur in up to
Other forms of congenital or genetic forms of cardiomyopathy can also cause sudden cardiac death but are less common. They include:
- arrhythmogenic right ventricular cardiomyopathy (ARVC)
- dilated cardiomyopathy
- left ventricular noncompaction cardiomyopathy
Acquired coronary artery disease is the most common cause of sudden cardiac death in older adults. Although it is rare in young people, congenital conditions that affect the coronary arteries — the blood vessels that supply blood to the heart — can also cause sudden cardiac death in this population.
Other possible causes of sudden cardiac death in young people include, but are not limited to:
- congenital valvular anomalies, such as mitral valve prolapse
- structural abnormalities in the aorta
- inherited or acquired forms of arrhythmia, such as long QT syndrome
- ion channelopathies
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However, in the absence of a previous history of cardiac arrest, predicting sudden cardiac death can be difficult. In many cases, people may not have received a diagnosis of the underlying cause of disease, and they may show no or minimal symptoms without strenuous activity.
The most common symptoms that may present before sudden cardiac death are often associated with abnormal heart rhythms. These typically include:
- a fast, heavy, or fluttering heartbeat, known as palpitations
- chest pain, especially with activity
- fainting
- seizure
People who may be at risk of other forms of heart disease should be aware of additional symptoms associated with those conditions. These may include:
- shortness of breath, especially with activity
- dizziness or lightheadedness
- excessive tiredness
- swelling in the lower part of the body
If a young person is experiencing symptoms consistent with potential heart disease, they should undergo an evaluation by a healthcare professional. They may wish to consider limiting strenuous activity until they have received the results of a cardiac workup.
In most cases, with early intervention and proactive management, it is possible to prevent sudden cardiac death. However, this is reliant on people being aware of any underlying heart abnormalities, or risks for heart abnormalities, for which they can receive appropriate treatment.
Treatment to prevent sudden cardiac death is dependent on the type of underlying disease and may involve medication, surgery, lifestyle changes, or a combination of these interventions.
In people at high risk of sudden cardiac death, research has shown the implantation of an ICD as a primary form of prevention to disrupt potentially life threatening episodes of arrhythmia by up to
Doctors may also advise young people with genetic or congenital heart abnormalities that put them at increased risk of sudden cardiac death to adopt a heart-healthy lifestyle. This may include a heart-healthy diet, smoking cessation, and light physical activity. They will generally discourage intensive physical activity, although this depends on individual risk factors.
The wide publicizing of sudden cardiac death, particularly in young athletes, means that there is increasing interest in proactively screening all young athletes for heart conditions that may increase their risk of fatal complications.
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- a family history of sudden cardiac death
- evidence of left ventricular hypertrophy
- a history of unexplained fainting
- arrhythmias
There is still debate in the medical field regarding whether people with heart abnormalities should avoid physical activity. Among people with HCM, which is the most common cause of sudden cardiac death in young people, most cases are benign. Limiting physical activity in all cases may, therefore, be unnecessary.
A personalized approach to physical activity recommendations may be appropriate. That means that healthcare professionals make the decision on a case-by-case basis depending on the underlying risk of fatal complications and the ability to prevent these events.
The AHA recommends that individuals at increased risk should not participate in strenuous activities if it is not possible to provide effective treatment for the underlying heart abnormality.
While there is no definitive recommendation, experts generally consider moderate-intensity physical activity to be safe for people with heart abnormalities and believe that it may help maintain overall heart health.
Sudden cardiac death in young people is rare but often alarming and traumatic. Although these tragedies may seem unpredictable and unavoidable, proactive screening and care can help prevent sudden cardiac death in many people with underlying heart abnormalities.
If a young person is experiencing any symptoms of cardiac dysfunction, especially during physical activity, they should consult a doctor right away to assess their heart health.