Hello Natsnan it's great that your healthcare professionals are doing all the tests, but with luck your outcomes will be as positive as mine. I have something similar to your description, called an ectopic heartbeat, which started eighteen months ago when I was very stressed. (It 'skips' a beat about one in 4, and really pounds furiously at times). I had blood tests for thyroid, the 24 hr monitor, exercise ECG, CT scan (that one didn't work, because my heartbeat is too irregular) and MRI scan. I had beta-blockers which had no effect on the beat, but made me feel really weird. Tests all showed my heart is healthy, no artery or cholesterol problems at all. My consultant said it is entirely benign, just one of those things. GP gave me the choice of continuing the beta blockers which I refused. It is still there, but I do think it is stress related. The most important thing is to have all the tests you are offered, to put your mind (if not your heart) at rest! Let us know how you get on?