Sudden death in young people: Heart problems often blamed

Sudden death in young people is rare, but those at risk can take precautions. Find out more about the risk factors, causes and treatments.

By Mayo Clinic Staff

Sudden death in people under age 35, often due to hidden heart defects or overlooked heart abnormalities, is rare. When these sudden deaths do occur, it's often during physical activity, such as participating in a sporting event.

Millions of elementary, high school and college athletes compete every year without incident. Fortunately, if you or your child is at risk of sudden death, there are screening tests for heart defects and precautions you can take.

How common is sudden cardiac death in young people?

Nearly 360,000 sudden cardiac arrests occur outside of hospitals each year in the United States alone. Of those sudden cardiac arrests, very few occur in young people, and only some of those young people die of sudden cardiac arrest. Most deaths due to sudden cardiac arrest are in older adults.

What can cause sudden cardiac death in young people?

The causes of sudden cardiac death in young people vary. About two-thirds of the time, death is due to a heart abnormality.

For a variety of reasons, something causes the heart to beat out of control. This abnormal heart rhythm is known as ventricular fibrillation.

Some specific causes of sudden cardiac death in young people include:

  • Hypertrophic cardiomyopathy (HCM). This is a disease in which the heart muscle (myocardium) becomes abnormally thick, making it harder for the heart to pump blood.

    Hypertrophic cardiomyopathy, while usually not fatal in most people, is the most common cause of heart-related sudden death in people under 30. It's the most common cause of sudden death in athletes. HCM often goes undetected.

  • Coronary artery abnormalities. Sometimes people are born with heart arteries (coronary arteries) that are connected abnormally. The arteries can become compressed during exercise and may not provide proper blood flow to the heart.
  • Long QT syndrome. Long QT syndrome is an inherited heart rhythm disorder that can cause fast, chaotic heartbeats. The rapid heartbeats, caused by changes in the part of your heart that causes it to beat, may lead to fainting. These irregular heartbeats can be life-threatening.

    In some cases, your heart's rhythm may be so erratic that it can cause sudden death. Young people with long QT syndrome have an increased risk of sudden death.

Other causes of sudden cardiac death in young people include structural abnormalities of the heart, such as unrecognized congenital heart disease and heart muscle abnormalities.

Other causes include inflammation of the heart muscle, which can be caused by viruses and other illnesses. In addition to long QT syndrome, other abnormalities of the heart's electrical system, such as Brugada syndrome, can cause sudden death.

Another rare cause of sudden cardiac death that can occur in anyone, though it's usually heard about in young people who play sports, is called commotio cordis. It occurs as the result of a blunt blow to the chest, such as being hit by a baseball or hockey puck, at just the right time. The blow to the chest can trigger ventricular fibrillation if the blow strikes at exactly the wrong time in the heart's electrical cycle.

Are there symptoms or red flags parents, coaches and others should be on the lookout for that signal a young person is at high risk of sudden cardiac death?

Many times these deaths occur with no warning, but symptoms to watch for include:

  • Unexplained fainting (syncope). Sudden and unexplained fainting that occurs during physical activity could be a sign that there's a problem with your heart.
  • Family history of sudden cardiac death. The other major warning sign is a family history of unexplained deaths before the age of 50. This obviously isn't a physical symptom like fainting, but deaths like this in your family should prompt you to pay close attention and perhaps talk with your doctor about screening options.

Shortness of breath or chest pain may also be a sign that you're at risk of sudden cardiac death, but these aren't common and may be a sign of other health problems in young people, such as asthma.

April 14, 2014