The kitten's heavy breathing sounds like it is not breathing, which may be caused by a cold, viral infection, or excessive nasal secretions. You need to observe whether the kitten has other abnormalities. If the kitten appears to be in poor spirits, If the cat has a runny nose, sneezing, etc., it means it has a cold, and you can give the cat pet cold medicine; if the cat has vomiting, diarrhea, or refuses to eat or drink, then it is a viral infection and needs to be sent to a pet hospital for examination and treatment in time.