What happens when someone having a heart attack gets to the hospital?

DEAR DOCTOR K: Can you tell me what happens when someone having a heart attack gets to the hospital?
DEAR READER: You're going about your day when you suddenly start to sweat and become short of breath. You feel a crushing pressure in your chest. You think: "This is it. I'm having a heart attack." A heart attack occurs when one of the coronary arteries, blood vessels that supply the heart, becomes fully or partially blocked.