Heart defects that can cause otherwise healthy athletes to die while playing in basketball and football games were detected in Harvard University athletes using a common $88 test.

The tests, known as electrocardiography or ECG, were given to 510 Harvard athletes in addition to their standard physicals, according to a study published by the Annals of Internal Medicine. The tests identified two players who were deemed healthy in typical exams despite having dangerous defects that should bar them from competition.

Genetic heart defects caused the courtside deaths of Hank Gathers, an All-America 23-year-old basketball forward at Loyola Marymount University, and Reggie Lewis, a 27- year-old All-Star guard for the Boston Celtics. Such defects are the top cause of sudden death in sports, killing 1 of every 220,000 young athletes each year, according to previous studies.

“Screening limited to medical history and physical examination fails to identify a significant percentage of athletes with increased risk,” wrote authors led by Aaron Baggish, a cardiology researcher and clinical instructor at Harvard Medical School and Massachusetts General Hospital in Boston. Still, he said, “our results may not end the complicated debate.”