Heart racing and pounding!

Hey ladies I am 38 & 4 worth my second baby, and about 10 minutes ago I was sitting at my desk chair and all of the sudden my heart started racing and pounding for like 3-4 seconds and then went normal. I work at a sheriffs office in dispatch so I have someone coming to take my blood pressure for me, but has anyone ever had this happen? If so what did you do? I'm a little freaked out. It was so sudden and has never happened before that I'm a little freaked out.