Unfortunately it can have the same symptoms as a real heart attack or stroke. Tightness and pain in the chest. A feeling of dizziness. Visual things like not being able to focus or darkness around the edges. For me the most pronounced thing is a crawling sensation under the skin of my head and down my face and the weird feeling that something is sticking out the side of my head. And yea, the intrusive thought that you're going to die, which your brain seems to rationalize with a bunch of stupid reasons.

You can also hyperventilate and not really notice it in your breathing. That makes your hands curl up by themselves and then pins and needles. I only got that once, after that I learnt some breathing exercises.