I too have wondered. My dd is a cancer survivor. She was 20 when she was diagnosed. One of the side affects of the treatment we were told about was that sometimes it causes heart damage and the it is possible for her develope life threatening heart problems.
They actually said that some patients just die suddenly without warning. Usually happens in their 30's. She is 28.
Truly scary.
Thanks Klue for doing such a wonderful thing. So sorry to hear about your dh's job. Hugs.