Punctate buds may have a heartbeat, if you can’t see it, the heartbeat may be weak and you should wait for a week or so for rechecking.
Dotted buds refers to the appearance of a small number of fetal buds within the gestational sac, the buds are very small, is the state of the emergence of fetal buds at the same time there may be a fetal heart, but generally the fetal heart is relatively weak, if you can not see the heart tube pulsation, you have to continue to wait for a week or so to check the ultrasound can be seen to make sure that there are buds and fetal heart development, proving that the uterus is a live fetus before the continuation of the pregnancy.
If there is no development of the fetal heart, then it should be considered as fetal arrest and the pregnancy can not be continued.
Whether or not there is a fetal heart in the dotted buds, the specifics should be determined by examination.