I have a long history of passing out, sometimes 2 X times a year somtimes not for 5 years, I am a 58 year old male.

There is often an apparent trigger - flue like symptoms or other. When an attack comes I know it is happening with hot cold feelings and nausia often common. I eventually collapse but not always become unconcious and only briefly. Have had ECG and a 24 hr tape test as well as an echo / test. No identified cause but am increasingly worried and the problem is taking increasing longer to recover from each time. Very white cold and clammy immediatly after but blood and other tests show as normal.