I foud out today I was 6 weeks pregnant with twins, but I am a bit concernd they could only get one heart beat on one sac but could not find one on the other, but could see a two separate sacs both with fetaus in them what's the chances of both being OK

Maybe its because, at this stage in their development, the heart beat is in sync between the two. What did the technician have to say, or your pediatrician ?