For 26 years Italy has had a heart screening program. By law, every Italian athlete, from elementary school through the pros, must have an EKG before he or she can play sports. Those with abnormal EKGs got other tests to see if their hearts are structurally abnormal.

Dr. Antonio Pellaccia of the Italian Institute of Sports Medicine and Science, an arm of the Italian National Olympic Committee, and his colleagues identified 81 athletes who had severely abnormal tracings from the 12,550 screening EKGs. Fourteen of them were Olympic athletes.

Despite there being nothing obviously wrong with their hearts, and nothing to disqualify them from competition, five athletes with abnormal EKGs developed cardiomyopathy. One died suddenly at the age of 24; another survived cardiac arrest, over the average follow-up period of nine years.