How long does it stop for. Could be PVCs or PACs. With these you get an extra beat followed by a compensatory pause. So it feels like your heart skips a beat.
could it maybe be a heart murmur?
all i know about that is your heart feels like it has stopped and it sort of sounds like it...my grandmother has had a heart murmer all her life. if you hear it, it kinda sounds like a few beats and then a pause. i dont know if it can occur occasionally like that. my grandma has them every few beats.
hope i was of help for you :/
good luck!!!