Quite true, also lots of people receive blows to their body in fights and such and don`t have a heartattacks.
Of course its not easy to say the cause of his death and thats why theres a second post mortem.
Just as I havnt been an alcoholic and in his shoes, also I havnt been a policeman in London and in theirs.
I guess none of us will really know what happened and its a shame that someone has died through what was supposed to be a peaceful protest.