My son was diagnosed with Sinus Tachycardia. The explanation the doctor gave was his heart was
compensating with his activity and we should have nothing to worry about. He is 2 years old and plays a lot.

My husband was once told by the doctor that he has tachycardia but he took a medication that help to normalize his heartbeat. His heartbeat is okay now but some times he gets exhausted and he feels his heartbeat is racing.

My son did not have any medication. And also, we have history of asthma (my father's side), does sinus tachycardia somehow related to asthma? Is it hereditary? or what?

Inputs please. Thanks!