AUSTIN, Texas  — Autopsy results show a 16-year-old South Texas basketball player who died last month suffered from a rare heart valve problem.

Robert Garza collapsed during a timeout in an AAU tournament game March 13 in Austin. Paramedics administered CPR and autopsy results released Wednesday by the Travis County medical examiner’s office show a defibrillator was used to try to revive him.

Garza was pronounced dead at a hospital about an hour later. The high school junior from Roma, about 250 miles south of San Antonio, had no history of heart problems.

The autopsy showed Garza had a condition known as congenital supravalvular aortic stenosis. It can restrict blood flow, occurs in no more than 10 percent of people with congenital heart problems and is more prevalent in males.