Fetal Heart Rate Pause

I had an ultrasound at 11 weeks pregnant which showed that my baby has a pause in his/her heart beat. It would beat a few times then pause for what would have been a normal beat and it continued this exact pattern during the whole ultrasound. Needless to say I'm very nervous about what this could mean. I've had 2 previous pregnancies with no problems as far as the babies go. My OBGYN said that this was rare when I asked how often he sees this. Baby measured 11 weeks 1 day on ultrasound and that was how far along I was so he said that was a good sign that it seemed to not be affecting his/her growth. I'm going in 2 days to see a perinatologist and they will do a fetal echocardiogram then. In the meantime I'm very curious if there is anyone out there with similar symptoms.
Thanks!