@milimi,
1) Do you feel my heart beating?
or
2) Do you feel my heart beat?
Both OK.
Do you feel [noun] [verb-ing]
Do you feel [noun] [verb]
Do you see my kite flying?
Do you see my kite fly?
Can you hear my sister singing?
Can you hear my sister sing?
However there is also a noun, "heartbeat". You can say "Can you feel my heartbeat?"