Sorry to hear about your dramas TerryP. I had similar issues a few years ago and went through various tests, 24 hour monitoring etc etc etc. No real outcome aside from the fact that the electrical system in my heart is wierd and sometimes acts up. Seems to be worse when I am over-tired or take too many stimulants, so I just need to sleep occasionally and not overdo the coffee.
Please let me know if you need access to medical journal aricles in future - I have access to most of them.