Hey, J. About 15 years ago I had my "heart Event" (they said it was a heart attack, but I never had chest pain, never lost consciousness, never saw any lights at the end of any tunnels, and never talked to any dead relatives...go figure). I had two arteries on my heart with almost 95% blockage. Like you, they never determined the cause and contributed it to hereditary factors. I had no symptoms up to this event, and I was informed that I could have been one of those that dropped dead in their tracks with no warning; I, they said, was very lucky. They stented me up and to this day I have yet to feel or hear my heart beat (yay modern medical technology!). Although 32 is very young for this, you have been forced to join an elite fraternity of us who have stared deeply into the abyss and lived to tell the tale. Even though I understand how hard it must be for you, the take away from this--at least for me-- is that none of us has any guarantee of any more then the moment we just lived or the breath we just took. I now live each moment as it may be my last, but I am comforted in the knowledge that doctors, and medical personnel can do wondrous, almost unbelievable, things if they get to me in time. Fortunately, I have no residual heart issues so I should live to a ripe old curmudgeonship, but I am also a pragmatist knowing I could assume room temperature at any given moment. I guess the best advice I would give a young person in your situation is just stop once a day and simply breathe, J..breathe.
BTW, if you have never had a heart attack, here's a few pointers. Be aware of any unusual pain starting in your arm, or chest. Mine started in the shower with my left arm feeling like I had pulled every muscle in the arm and no matter how I move it, I couldn't stop the aching (traditionally this is the left arm in the male, but, as I learned, it is usually the right arm in the female). I felt the pain move up my arm, skip my neck, and settle into my jaw. This was like no other pain I had ever experienced. Having grown up with a mother who was a nurse, I knew exactly what was happening. I immediately took an aspirin, told my wife to call 911 requesting an Advance Life Support EMT unit (in case I coded), and I sat down to wait trying to remain as calm as possible. This basically all you can do. In hind sight, the only other thing I would recommend if you're able guys, is to shave your chest. You'll thank yourself if you survive when those smiling angels of mercy gleefully rip off those monitor patches leaving you with squares of bare chest hair; one patch was the size of your hand, can you imagine!
I'm not trying to make light of a serious situation, but you take care of yourself, take your medicine(s), do what your doctors tell you, and you might be surprised the quality of life you can still achieve. Good luck.