Hi, I've recently quit smoking( 10 years on & off) and I'm on my way to a complete overhaul towards a healthier lifestyle. I used to have minor chest discomfort before for which I had consulted a pulmonologist. A chest xray was suggested and it came clear. I also feel fatigued and out of breath sometimes. I've read that smoking greatly increases chances of heart attack, and I can't seem to stop ruminating on the idea that I could have a heart attack. What all can I do to check if my heart is okay and continues to be okay?