What is the reason for a 7-month-old baby always sighing while sleeping?

Patient's question:

The baby always sighs when taking a nap; it used to take naps at night. Previous treatment and effectiveness: didn't care about what kind of assistance: help me guess a few times

Doctor's answer:

If it's an unconscious deep breath followed by exhalation, it looks like sighing, but it's actually a natural phenomenon of the human body and there's no need to worry. Your child often shows deep breaths or sighs. The two situations can lead to this.
Second: Myocarditis or myocardial damage in the child may cause it. (Often related to fever, caused by viral infections).
Third: Psychological factors may cause it.
Recommendation: It is recommended to first give the child an electrocardiogram (ECG) and blood tests to check myocardial enzymes.