I never thought about that...
I met maybe 3 different Gentlemen with apparent scares, and asked them all what they were from. When they said it was from heart problems, I only told them to tell me if I ever hurt them during our date. But never really thought about the possibility that they could maybe have a heart attack in my presence...
I would freak out if someone passed out or died in my company... Not sure I could help them either, as I don't know CPR...
I should definitely take a course for both work and private life, just in case.