Thanks for the query.
Sometimes ultrasound may not pickup the heart beat in very early pregnancy
Trans vaginal ultrasound
is better compared with trans abdominal scan in picking up heart beat in early gestation.
can affect the fetal growth but high HCG if within the normal range may not affect the baby.
So you wait for one more week and repeat the scan, possibly by that time the heart beat can be visualized.
Meanwhile you continue the medicines advised by your doctor.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429