Hey guys, That's my first post here, and I couldn't find any other place online where I can ask something like that and get rational scientific explanation. Here's what happened to me today and I have no idea what would cause it. I went to a coffee shop in afternoon to take a break from work. While I was standing in line I started to look at the electronic LED display on cashier's machine where shows how much you need to pay. Out of nowhere I start feeling my heart beat and the numbers on the screen start looking like a drop hitting a still water with each heart beat. It happened 2 times in a row. Then I shook my head off, then I looked at it again, it happened one more time and it stopped. I don't have any weird sicknesses, mental illness, and I don't do any drugs. Just went through a cold about a week ago. Honestly it does not make any sense to me, and it freaks the crap out of me. I hope it will never happen again, but still I'm trying to find any reasonable explanation to something like that. Any good feedback would be greatly appreciated, Thanks!