If it is 4 w 4 d counted the way doctors do, then you will not see anything. (In other words, if you mean it's 4 weeks 4 days since the first day of your last period.) If you happen to be counting from (presumed) conception, then you would be at 6w 4d the way doctors count it, and you should be able to see the heart beating.
I was 6 weeks 3 days. You probably wont see much, you might just want to wait til 6 weeks when you can see the heartbeat.
I had one at 5 weeks (4 weeks 6 days I think), and all they saw was a sac, no fetal pole or visible embryo yet.