sweeterthan

I think thats what they call it anyway. Once and a while I get these heart flutters that last like only 3 seconds at a time. I've had it for years and sometimes its like I sort of can't breathe when it happens, like I have to cough and I feel better...if that makes any sense. I'm pregnant and I get them from time to time and I'm just wondering if its anything to worry about. I didn't tell my doctor about it because I've had this probably since my early teens I think, I am 21 now. From what I know about it alot of people have this and its very common. Does anyone know why this happens? And is it anything to worry about in the future, can it cause a heart attack? Just wanted to inquire. Thanks.