The first, my husband (35 at the time). He was having chest pains off and on all day...I had no idea. Finally at about 8:00 P.M. he told me he thought he needed to go to the hospital. Trust me, when HE said it I took it seriously....he has major hospital-aversion!
The E.R. also took it seriously (it was packed at the time). He no more than told them his symptoms and he had monitors slapped on his chest; a chest X-ray; and other tests. Fortunately, it turned out to be digestive-related.
OTOH, a school friend who actually has a disease that can cause imbalance in electrolytes went to the E.R. and told them: "I am having a heart attack."
They sent him home. He stubbornly went BACK, only to code right in front of them. He was unresponsive for 15 minutes; but miraculously woke up and is fine except for some slight kidney damage.
Amazing the difference in care depending on who you first see. I've always said "Someone had to graduate last in their med school class!"
One other thing, for those who may be reading this thread. Even if you are young, heart problems can be caused by a WIDE variety of things.
We had another family friend (early 30's) whose heart stopped because of an antibiotic allergy...which had never reared its ugly head prior to the near-fatal attack. Fortunately, an alert family friend had noticed the shock symptoms, threw him into the car, and rushed to the hospital...he was there when it happened.