Arrhythmia??

Hey y'all. So today I had my anatomy ultrasound and our little man is growing ahead of schedule! The whole ultrasound we were asking questions and the technician told us his heart rate and everything was normal at 156! When I saw the midwife she listened and said there is an arrhythmia. Unfortunately my little guy was being stubborn and stayed curled up right under my belly button so she was unable to look at the heart. I go back in 2 weeks for a repeat ultrasound and to see an MD. Has anyone experienced this before??? I did some research and sometimes caffeine can be the culprit and I have to admit I've been drinking sodas every day 😕 I get migraines so couldn't cut it all the way out, but I definitely will now migraines or not!