BTDT, three years ago. Mine was a "little" incident, although the doc says there's no such thing as
little heart attacks. Never lost consciousness, never had to be revived, was just very short of breath after my 3 or 4 times a week bicycle ride. After an hour of sweating and panting, and then my fingers getting tingly (thinking to myself, "Hey, I've seen that on a list somewhere....") I had my daughter-in-law take me to the ER. They put a stent in one artery that was 50% and I was
instantly feeling better, sweats stopped, breathing recovered, but they wouldn't let me go home. Weird, that.... I was watching the screen where he could see the device going up the femoral artery and around the aorta and down into the heart, the little device dropping off the mesh tube at just the right place to open up that artery. It was actually kinda cool to watch! The ER cardiologist did say to me that it was a pleasant change to be conversing with his patient during the procedure!
Anyway, my point is, if you get funny feelings like that, even if there's no pain (there wasn't,) GET CHECKED OUT!
Best wishes for your friend's recovery!!!!