EPO caused a rash of deaths in top class cycling. Increase in number of red blood cells effectively thickening the blood leading to heart attack.
indeed, such was the risk that many pro riders would set their alarms a couple of times a night and get up to excercise, in order to minimise the chance of their blood getting so gloopy that their heart stopped in their sleep.
It would be prudent to wait for a post mortem before we get too carried away though. It is extraordinary how many super-healthy and drug-free people do just keel over. It is more apparent now, as most medical ailments have become easier to prevent, predict/detect in early stages, or treat when they happen. SADS is not one of them, and in the light of so many other advances in medicine, it seems to stand out more when it does happen.
Very sad indeed, I feel so sorry for his parents: no one should have to outlive their children.