Very similar experience: heart palpitations, racing heart, difficulty breathing. I was a little younger than you at the time (just turned 40), and I didn't smoke, but otherwise your description of yourself sounds a lot like me. Ambulance to the ER, insane number of tests performed, all the tests were normal, but they put me on a medication to slow down my heart rate and regulate the rhythm. Stayed on that for a couple of years, then they took me off of it. Guess it wasn't needed anymore.
Now for the really cool part. After that incident, the roof was torn off (so to speak) and my intuition and "psychic" abilities were completely opened. It was both a blessing and a curse because I was able to see, but we always forget that we only see the possibilities (free will still has the deciding factor in all situations) so I was going around telling people what I saw and when it didn't happen they labeled me nuts and moved on. What I learned was to follow that wide open intuition and be fully in the present moment and don't focus on the future and what COULD happen because we are constantly creating our future as we live our present. This took me a while to fully incorporate because there was a lot of old programming to be replaced.
Meditation can happen in different ways. It is easier for me to meditate when I'm walking through the woods or hanging out by water. The point is you don't have to follow any set of rules to meditate and get answers. You only need to get quiet and open to receive. Some people can do this by doing their meditations in the classic way that we always picture meditation, and some people need to move their bodies. Anything that gets you out of your mind and all the chatter in there can help.
I hope these ramblings help you a little.
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