Heartbeat 

To dream of hearing heartbeats rather than seeing the actual heart indicates the blindfolding of your true emotions.

To dream of a heartbeat can also refer to life. You are too used to the sound of a heartbeat that you do not put much thought on it - same as everything else you take for granted.

Similarly, you might also dream about hearing your heartbeat pounding through your chest whenever you are afraid, threatened, or overstressed.