1. An American Heart Association site is shown below which discusses bypass. Basically they take a vein (most likely out of your leg(s)) and use it to bypass clogged arteries feeding blood to your heart muscle. To begin with there is some swelling of the legs because the veins are gone but this gets better over time.
2&3.Genetics are a strong indicator or coronary artery
diease. Both my parents had problems ( my mother died from it) and I found I'd had a massive heart attack
(silent) within 5 years when I was 44. When I went in my cholestrol
was 110. Plaque
ruptures are a likely cause of blockages. See link.
4. You really should get checked out throughly. The risks are extremely high. I suggest you discuss the matter with a cardiologist if you have an opportunity. I personally would not rely on a GP. I have included a link on heart attack symptoms. If you get dizzy or winded go NOW.
Bonus: Heart attacks can have many different symptoms ranging from the classic Fred Sanford movie heart attack to no symptoms at all. Silent heart attacks are particularly dangerous because the heart compensates by working harder and enlarging resulting in heart failure
which is deadly. The moral is to go to the hospital if you feel the least bit wierd. That little pain that came and went may be your only warning.
I'm a CHF patient, 22% EF.