I have suffered for years from episodes of fast heart beat. It can be very strong and disturbing, and I have ended up in hospital but it goes away after a few hours and they could never find anything wrong. For a while I was getting it every afternoon. Eventually I worked out it happened on the days I ate bread. A friend suggested it might be the preservative in bread. When I eat Brumbys' bread I have no problems, but when I ate some preserved bread without thinking at my mother's place, I had another episode. - NT