Wouldn't surprise me if him being an athlete running around at full tilt for 90 minutes a week twice a week (plus training the other 5) helped trigger the whole thing, but at the same time being an athlete meant he could pull through like it looks like he is doing.
The human body is a funny thing at times.
The fact he is a young athlete is one of the reasons he took bad.
http://en.wikipedia.org/wiki/Hypertrophic_cardiomyopathy