For years, a debate has raged over whether high school athletes should have a heart test, known as an ECG, before they’re allowed to play sports.

To some, it’s the only way to make sure a young competitor doesn’t have a hidden heart defect that could turn fatal on the field.

But a new study by a Minnesota heart specialist says the test might not save as many lives as people think. Dr. Barry Maron, who studies sudden death in young athletes, took a close look at 13 reported cases in Minnesota since 1986. He found that only four, or 30 percent, had heart conditions that could have been detected with an ECG.

Every one of those deaths “is catastrophic, tragic,” said Maron, a cardiologist with the Minneapolis Heart Institute Foundation, who presented his study at the American College of Cardiology last week.

But he said the risk, statistically speaking, doesn’t justify giving ECG tests to every young athlete in America.

As it is, only three countries — the United States, Israel and Italy — screen student athletes for medical risks. But ECGs (electrocardiograms), which cost about $150, aren’t part of the U.S. routine. Most states require only a physical exam and medical-history questionnaire.

Advocates have called for adding ECG tests, as Italy has done. Sometimes, the campaigns are led by families hit by personal tragedy. One group, called the Nick of Time Foundation, even sponsors free ECG tests for student athletes in Washington State. By its estimate, more than 100 healthy young athletes die of cardiac arrest in the U.S. every year.

In 1998, Maron himself took states to task for failing to do enough to screen student athletes for heart conditions. Since then, he said, the questionnaires have improved, and they’ve helped identify students with underlying heart problems.

But mandating ECG tests, he says, would be a “mind-boggling” enterprise and miss “a significant proportion” of cases. “No screening program, even with a test like the (ECG), can be expected to identify all athletes at risk,” he said.