6 weeks and 3 days pregnant. us showed gestational sac and fetal pole shown, no heart beat. hcg decreased from 17407 to 10943. is this a problem?

Yes: I am more concerned with the falling HCG than the lack of Fetal heart at 6 wks. If the dates are wrong, the fetal heart beat may not be visible. This can be checked by repeating the U/S in two weeks. Falling HCG is abnormal at this stage of pregnancy. I recommend you have it rechecked and the U/S repeated. The image is of a 6 wk preg. See how small the fetus is. It is easy to miss a heart beat