breathe/wheeze heavily

  1. I have ASD problem in my heart. If I go fast, I have to breathe heavily.
  2. I have ASD problem in my heart. If I go fast, I wheeze heavily.
    Which is the right expression? Please correct?

Both expressions are gramatically correct but in my opinion, and I’m not a doctor, have slightly different meanings. No. 1 means that you are short of breath after going fast. No. 2 means that you not only breathe heavily, but your breathing is also noisy and ‘chesty’.

  1. Since I have ASD problem in my heart when I go fast, I breathe fast.
  2. Since I have ASD problem in my heart and when I go fast, I breathe fast.
    Please correct the above sentences.

Sentence 1, the comma needs to be moved between ‘heart’ and ‘when’. If you leave the comma where it is, it suggests that you only have the ASD problem when you go fast, which I don’t think is the case.
Sentence 2 suggests that you have breathed fast ever since you the ASD problem, whether you go fast or not.
Both sentences would sound better with an ‘an’ or ‘the’ before the ASD.