Updated

The death of a 4-year-old boy after he went on a rocket-ship ride at Walt Disney World was caused by abnormal cardiac rhythms from a heart condition that he apparently had since birth, according to an autopsy released Tuesday.

Daudi Bamuwamye died after riding "Mission: Space" in June. He had an abnormality of the heart muscle called idiopathic myocardial hypertrophy, with fibroelastosis of the left ventricle, the Orange County Medical Examiner's Office said.

"People with this condition are at risk for sudden death throughout their life due to abnormal electrical heart rhythms," the medical examiner's office said. "This risk could be increased under physical or emotional stressful situations. This condition may also eventually lead to heart failure."

The $100 million Epcot ride, one of Disney World's most popular, was closed after the death but reopened after company engineers concluded it was operating normally.

"Mission: Space" spins riders in a giant centrifuge that subjects them to twice the normal force of gravity, and it is so intense that some riders have been taken to the hospital with chest pain.