Miss,
I have definitely been in your shoes and have had very scary and similar things happen to me. Once, after exercising, my heart took off, and felt as though it were fluttering in my chest. I grabbed my blood pressure monitor and my pulse was 150 beats per minute but my rhythm was normal (my cuff can detect abnormal heart rhythms). Then another time, this one landed me in the emergency room, I laid down for bed and my heart started racing and felt as though it was flip-flopping and when I came to the ER my pulse was 160 beats per minute. After numerous tests, a diagnosis for SVT and then a retraction of a diagnosis of SVT, the cardiologist said it was just anxiety/panic and that my heart was fine. Then, under severe stress of course, I had palpitations, huge palpitations to where it felt like my heart stopped, and this sent me back to the cardiologist. What I have found in my experiences, my numerous experiences, is that panic and anxiety cause these reactions, even if you don't even realize it until after the fact. I started taking a supplement of magnesium twice a day (consult your physician before taking any supplement ;))and doing breathing techniques. And like the support specialist said, try to talk to yourself and tell yourself that this has happened before, you are fine, it will go away in a few minutes, and that your heart is healthy and nothing is wrong. I started doing these things and in that first minute, when the shear terror is at its highest, it doesn't seem to work but I keep doing it and it does seem to help. I still have attacks, mostly in class, but I have noticed that they are decreasing in their length and in their strength. When you talk to yourself and say it is going to be ok and that you always survive and that it is scary right now but will go away, you are exerting some control over the situation and being rational instead of thinking, "OMG, I am having a heart attack, it is atrial fibrillation, this is it I am having a stroke!" Trust me, been there and done that and still do it every once in a while but it is getting better. My heart palpitations are virtually nonexistent now which is a total blessing because those make you feel like something is really wrong with your heart rhythm and that you could die at any