An estimated 1 to 3 per 100,000 apparently healthy young athletes develop an abrupt-onset heart rhythm abnormality and die suddenly during exercise. Males are affected up to 10 times more often than females. Basketball and football players in the United States and soccer players in Europe may be at highest risk.
Causes
Generally, the causes of sudden death during exercise are very different in young athletes than in older athletes. However, in all athletes, asthma, heatstroke, and the use of performance-enhancing or recreational drugs may cause death due to sudden abnormal heart rhythms.
Young athletes
In young athletes, the most common cause of sudden cardiac death is
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Undetected, abnormal thickening of the heart muscle (hypertrophic cardiomyopathy)
Other heart disorders, such as long QT syndrome or Brugada syndrome that cause abnormal heart rhythms, and aortic aneurysms may also cause sudden death in young athletes.
Less commonly, undetected heart enlargement (dilated cardiomyopathy) may be present in a young person who has no symptoms, and the person may die suddenly during or after vigorous exercise.
Abnormalities of the coronary arteries (coronary artery disease), especially when one of the arteries takes an abnormal path through, rather than on top of, the heart muscle, may also cause sudden death in athletes when the compression cuts off blood flow to the heart during exercise.
Rarely, young, thin athletes may also have sudden heart rhythm disturbances if they experience a strong blow to the area directly over the heart (commotio cordis) even when they have no heart disorder. The blow often involves a fast-moving projectile such as a baseball, hockey puck, or lacrosse ball or impact with another player.
Older athletes
In older athletes, the most common cause is
Occasionally, hypertrophic cardiomyopathy or heart valve disease is a cause.
Symptoms
Diagnosis
Screening
People are commonly screened by their doctor before starting an exercise program. Doctors screen people who have medical disorders and also those who do not think they have any medical disorders. People without known medical disorders should typically be checked because some serious disorders do not cause problems until people exercise. People in the United States are reevaluated every 2 years (if high school age) or every 4 years (if college age or older). In Europe, screening is repeated every 2 years no matter what the athlete's age.
Doctors always ask people questions and do a physical examination, but they do testing only when the person's age and reported symptoms are cause for concern. Questions focus on three areas:
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Symptoms such as chest pain or discomfort, fainting or near-fainting, fatigue, and difficulty breathing, particularly when these symptoms occur during vigorous exercise
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Family history, particularly any history of family members who fainted or died during exercise, or who died suddenly before about age 50
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Use of drugs
The physical examination focuses on listening to the heart with a stethoscope for heart murmurs that indicate a possible heart disorder and measuring blood pressure with the person lying down and again while the person is standing.
For younger people, doctors typically do not do any tests unless something abnormal is identified in the person's history or is found during the physical examination. Routine use of electrocardiography (ECG) screening of young athletes is not considered practical in the United States. However, if findings suggest a heart problem, doctors typically do ECG, echocardiography, or both.
For people over age 35, doctors may also do ECG and exercise stress testing before approving vigorous exercise.
If a heart disorder is found, the person may need to stop participating in competitive sports and undergo further testing. Some people with severe heart disease, such as hypertrophic cardiomyopathy, should not participate in competitive sports. However, most people with heart disease may participate in noncompetitive sports. Increased activity is directly related to better health outcomes such as a decrease in "bad" cholesterol levels (low-density lipoproteins), prevention of high blood pressure, and reduction of body fat. Regular exercise is routinely included in care plans for people with most forms of heart disease (cardiac rehabilitation).
Treatment
If people stop breathing and collapse, immediate treatment is with
Resuscitation is continued in the emergency department. If the person survives, doctors treat the condition that caused the abnormal rhythm. Sometimes doctors place an implantable cardioverter-defibrillator, which continually monitors the person's heart rhythm and delivers a shock to return the rhythm to normal if needed.
Automated External Defibrillator: Jump-Starting the Heart
More Information
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
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Nick of Time Foundation: This organization works to increase survival of sudden cardiac arrest with awareness, "hands-only" CPR training, advocacy for having defibrillators in all public places, and access to screening for young athetes.
