Heart attacks are still not very predictable, but they've decreased amazingly over the past decade or two.  At a time when there's concern about rising death rates, heart disease has been a great success.  CDC has good advice.  

Sudden, unexpected death still happens regularly.  Someone I saw weekly, who had fairly minor health problems but was fit and busy, died suddenly a month or so ago. He'd just been to see a doctor.  

So it's a good idea to live mindful that death can come whenever, and to set things up so as to make things as simple as possible for family and friends (and business if you have one).  I tend to carry around an expired driver license for ID.  I should get something more elaborate to cover a heart problem.