Two colleagues of mine have had heart attacks in recent years. Thankfully they both survived and are lucky to have been treated quickly. One of them mentioned the "widow maker artery" and he was VERY lucky. Now their doctors have said they are as fit as ever. Neither of them, IMHO, looked remotely obese and both looked after themselves.
My understanding of the pilot medical is that it is largely a snap shot. It does not mean that the AME will be able to detect an undiagnosed condition similar to those experienced by my colleagues.
As far as the comments regarding the particular pilot involved in this particular incident I think a little respect for this unfortunate chap is in order. Some of the comments are very insulting and irrelevant to the thread.