Thanks for your replies. I have just read about the vagus nerve. However I did go to the doctor on the ship, she was lovely, did an ECG, bloods, abdominal X-ray, BP, checked all my pulses from ankle to neck and had a really good feel around my abdomen . She found all to be ok, and told me when I get the fluttering feeling to take a deep breath, hold my nose and breathe out hard against the back of my hand!! Also gave me three pills take take if needed..alprozalam.....don't know them but to calm me I assume. I've only taken one so far as the manoeuvre above appears to have done the trick, she explained how it works, I was a little sceptical but the fluttering/pulsing has completely stopped, I did it three times that's all but she said to do that whenever I needed to together with slow deep breaths. I hope it's not going to come back....