A study released Saturday examining more than 3,000 college athletes who had COVID-19 found so few instances of heart-related issues that future cardiac testing might be used only for athletes with certain symptoms.

In the study, published in the American Heart Association's journal, Circulation, researchers found signs of possible, probable or definite myocarditis, or heart inflammation, in 21 of 3,018 athletes (0.7%) who had tested positive for COVID-19. It also showed that athletes with heart issues were more likely to have had moderate COVID-19 and/or cardiopulmonary symptoms.

Dr. Jonathan Drezner, director of the University of Washington Medicine Center for Sports Cardiology and a co-principal investigator of the study, said the results will help colleges and the NCAA refine cardiac-screening protocols for athletes who have tested positive for COVID-19.

"The bigger message is for the athletes who only have mild symptoms or no symptoms, it's not clear you need to do any testing at all," he said. "And I would be comfortable simply doing a good review of symptoms and making sure when they get back to play, they feel well."

Drezner has been a consultant for the NCAA, and NCAA chief medical officer Dr. Brian Hainline was on the study group's steering committee. The study included male and female athletes from 42 colleges and institutions across 26 sports.