Why does my heart seem to beat slowly at times?

Well i used to get anxiety attacks and take pills for it, but i don't anymore. Once at work my heart seemed to beat in slow-motion. I felt two beats then a short pause before two more beats and a pause, which made me think it was just the one heart beat, but my heart was in slo-mo. it only lasted a few seconds and then it went back to normal. could this be part of an anxiety attack? i get them on occasion still when my heart seems to beat like its working really hard or at times it will seam to beat at random going fast and then slow.