For about a month I have felt my heart flutter and at that very instant it is as if my breath is taken away. It is so fast that it is not uncomfortable but it makes me very worried. I feel it mostly in the afternoon and evening. I have never had anything like this; infact, I have never really felt my heart flutter. I had run a 10K run last November 2009 and they did a 20 minute heart test with all these suction cups on my body and an ultra sound machine next to me. After, they said my heart was fine and great to run the race. I did run and there wasn t a problem. I took this report, given to me by the Cardiologist for the run to a new doctor (Cardiologist) near my home and he listened to my heart, looked at the report and said my heart is great. He advised me to check my Thyroid. What could this be? I am 40, eat well, non-smoker and exercise on a regular basis. Thank you for any advise. Millie
Hello, Regarding your concern, I would explain that your symptoms could be related to possible cardiac arrhythmia.  Anxiety or a panic disorder cannot be excluded either. Coming to this point, I would recommend performing an ambulatory 24-48 hours ECG monitoring in order to examine your heart rhythm trends for a prolonged time and exclude possible cardiac arrhythmia.  I would also agree with your doctor on the recommendation of checking thyroid hormone levels, in order to exclude possible thyroid gland dysfunction.  Hope I have answered your query. Let me know if I can assist you further. Take care Chat Doctor.