Many colleges/scholarship applications have an optional section that asks for “additional circumstances” or things you would like them to know.
Would it be necessary/useful to write briefly about a congenital heart condition, if it affected your daily life but did not affect academics at all?
If I didn’t affect your academics at I, I wouldn’t talk about it. I believe the intent of the question is specifically to ask about things that did affect your high school career.
Then again, I’m just a student, so you might want to ask your guidance counselor for advice on this.
If it’s something that hasn’t had an impact on your academics at all (for example, if you haven’t done poorly in school as a consequence of the condition), then no, you don’t need to mention it. If it’s greatly hindered your ability to participate in extracurricular activities (I don’t know a lot about heart conditions…is this something that has affected your ability to participate in ECs?), then that might be something to mention.
I second asking your guidance counselor.