Most states require that high school athletes undergo a physical examination before participating in sports, in part to identify students who have an underlying condition that could lead to cardiac arrest.

But the ability of such screening to identify students at risk of sudden cardiac death is “questionable,” according to a Missouri physician.

Part of the problem is that sudden cardiac death in young athletes is so rare, affecting fewer than 10 students per year nationwide, according to Dr. Dennis Y. Wen, a family practice physician at the University of Missouri in Columbia.

Screening for such a rare condition may cause “needless anxiety” for many students and parents when doctors find apparent cardiovascular abnormalities that turn out to be harmless, Wen told Reuters Health in an interview.

“The vast, vast, vast majority of the abnormalities you’ll find will end up being nothing,” Wen said. “You have to find a whole lot of nothings to find something.”

On the other hand, a clean bill of health does not mean that an athlete is not at risk for sudden cardiac death, Wen said.

Parents and young athletes should understand the limitations of screenings. “The examination is not going to find every problem that might be dangerous to the athlete’s health,” Wen said.

Sudden cardiac death occurs when a person’s heart abruptly stops functioning, and it sometimes happens in apparently healthy people without any symptoms of heart disease.

The most common cause of sudden cardiac death in young athletes is a heart condition called hypertrophic cardiomyopathy, which causes the heart’s walls to thicken. As the walls thicken, pumping blood becomes more and more difficult for the heart, which increases the risk of heart failure or sudden death from cardiac arrest.

Detecting hypertrophic cardiomyopathy can be extremely difficult, according to Wen. Medical textbooks describe a characteristic heart murmur caused by the condition, but Wen says that most people with hypertrophic cardiomyopathy do not have an audible murmur.

“Sudden death may be the first symptom,” he said.

In an article in the June issue of the journal The Physician and Sportsmedicine, Wen reviews the possible causes of sudden cardiac death in young athletes, as well several methods of screening young athletes.

The most common screening, which is endorsed by the American Heart Association, involves a physical exam and a medical history. Other screening methods, which have advantages and disadvantages, include echocardiography, electrocardiography, MRI and genetic testing.

None of the various methods meets the standards of an effective screening tool, in large part because sudden cardiac death in young athletes is so rare, Wen said.

Despite the limitations of screening, Wen still recommends that young athletes undergo a physical examination before participating in sports. But it is important that the people recognize the limitation of screening, he said.

SOURCE: The Physician and Sportsmedicine, June 2004.