Daudi Bamuwamye, aafter going on the rocketship ride "Mission: Space" at Epcot, had an abnormal thickening of his heart muscle caused by a condition present since birth, doctors said Tuesday.
Jerra Kirby, a 12-year-old girl from Newport News, Virginia, whowater park in August, died from arrhythmia caused by an early-stage viral heart infection, officials also determined.
People who suffer from the young boy's condition are at risk of sudden death throughout their lives, the medical examiner's office said.
"This risk could be increased under physical or emotional stressful situations," Dr. Jan Garavaglia wrote. "This condition may also eventually lead to heart failure."
Disney officials released a statement Tuesday saying that "our sympathies are with the families during this difficult time. In regard to the reports, we believe they speak for themselves."
The $100 million Epcot space ride, one of Disney World's most popular, was closed after the boy's death but reopened after company engineers concluded it was operating normally.
It spins riders in a centrifuge that subjects them to twice the normal force of gravity. Some riders have been taken to the hospital complaining of chest pain.
One warning posted last year in front of the ride read: "For safety you should be in good health, and free from high blood pressure, heart, back or neck problems, motion sickness or other conditions that can be aggravated by this adventure."