My heart attack experience was like many of yours, I thought I was in good health. I was 68 and walked 3-4 miles daily for 12 years, I wasn't over weight( 155 lbs and 5'10) and was careful with my diet, none smoker, non drinker.
My symptoms began around 9 PM February 2007 while we were watching TV in our motor home, we were in Arizona doing the snowbird thing.
I started belching and felt like I had gas, after a few minutes I stood up thinking that I could get relief if I could just belch the gas out. After a few minutes I decided to lay on the bed for relief and soon noticed that my arms felt heavy and a squeezing at each of my wrists.
I asked my wife to dial 911 and informed her that I thought I may be having a heart attack, she called but was concerned that this might be a false alarm. The paramedics arrived quickly and confirmed that something was going on. At the hospital the on call cardiologist informed my wife that indeed it was a heart attack requiring immediate attention and that the next few hours were critical. I was moved by air ambulance to Phoenix and had four bypasses the next morning.
The surgeon told me that on a scale of 0-10 mine was a 10 and that I have considerable heart damage. Five days after being released I had more problems, congestive heart failure and double pneumonia, two weeks in the hospital and then four stints to hold the new bypasses open. I lost 14 lbs in the process.
I was unable to drive us 1300 miles back home. After having help getting home I needed to visit the emergency room twice for pericarditis. I didn't start feeling 100% for six months but have felt good since other than a few side affects from the med's. I resumed walking just as soon as I was strong enough and walk 3-4 miles daily. Hope I'm good for another 68 years.