That’s fair. I do wonder how they knew she had a “heart condition” if it wasn’t diagnosed when she was alive. That conclusion could just be speculation or guesswork.
But your heart doesn’t have to stop for you to pass out. Some young people do have conditions that cause fainting, and fainting without underlying conditions may actually be more common in the young than in the old.
Death rate of young dying from fainting accidents. I could not find it. The chances of an extremely young marathon athlete fainting and dying has to be a close as to winning the lottery. I think even a person fainting has a survival reflex to prevent massive injury.
I seen people faint in the Marines from locking their knees while standing in attention for long periods of time. They collapsed straight down, like they were falling in on themselves. Never once was any of them hurt or hit there head hard.