She had undergone a routine physical exam a few months earlier; it revealed only that Shanin Suminski, a 22-year-old teacher, was a reasonably healthy young woman with every expectation of a long, productive life.

So much for confidence in the future: Shanin Suminski's ended abruptly on Jan. 18, the day before she was to take a learning disabled sister to see a play, when she collapsed and died during a pickup game of floor hockey with her brother and several friends.An autopsy revealed the cause of death, and it sounded like something old people die of. Myxomatous mitral valve, according to cardiac pathologist Lynda Biedrzycki, medical examiner in Waukesha County, Wis., is a condition in which the mitral valve degenerates into a spongy mass; that, in turn, can cause arrhythmia and even lead to cardiac arrest.

"I get these cases all the time," says Biedrzycki, who does cardiac consulting for the Milwaukee County medical examiner's office. "(Young) people die at home or when they are just playing basketball in their backyard."

Statistically, the overall chances of a high school student dying during an organized game or practice session are one in 200,000. But Biedrzycki's work suggests the risks extend to teenagers and those in their early 20s who aren't in organized sports, too.

Barry Maron, director of cardiovascular research at the Minneapolis Heart Institute, agrees that the frequency is much greater than one in 200,000, and he acknowledges the difficulty in spotting potential problems through routine physical examinations.

Most doctors take a family history and listen to the heart with a stethoscope, whether or not the young person is an athlete. But such physicals will pick up only a tiny percentage of cases involving the 20 or so rare heart conditions that can cause near-instant death in a teenager.

By adding an electrocardiogram, which displays the electrical activity of the heart and costs $50 to $75, and an echocardiogram, which examines the heart by ultrasound and can cost as much as $1,000, doctors can spot more than 50 percent of the cases, Maron says.

For example, because Shanin Suminski's condition could have been inherited, her father, Steve, decided to have his four minor children examined by a pediatric cardiologist, who administered electrocardiograms to each of them. All four were normal. A 24-year-old son chose to forgo the testing.

Maron sympathizes with parents who might want to go beyond the standard physical exam. "That's called peace-of-mind screening," he says.

Stuart Berger, associate professor of pediatrics in the cardiology department of the Medical College of Wisconsin, understands the impulse as well. "I don't think (people) would be acting irrationally," he says. "People are legitimately scared."

Are additional diagnostic tests worth the cost? Berger's response: "If it's my kid, you're damn right it is."

But Maron and Berger also agree that the risks are incredibly small and that mass screening is not the answer.

The American Medical Association concurs. The high cost of diagnostic tests and the low rate of potential heart ailments, the AMA says, makes mass screenings of high school athletes impractical.

At $500 per case, it would cost $250,000 to detect one previously undiagnosed case.