First, having a gun to your head is important for motivation. The
heart attack would cover that.
Triples risk of another heart attack; maybe more.
Second,
nicotine replacement doubles your likelihood of quitting. This includes nicotine patches, gum, even E cigarettes BUT nicotine has some effects on the heart and this should be run by your heart doctor prior to starting.
Third. It is an addiction. Behavior change is done by a variety of modifications of your EXTERNAL environment. Thinking good thoughts as you know Does Not Work on addictions.
So....
1) set a quit date and tell everyone about it. Personally, I had my religious group pray for me on that date.
2) get cigarettes, lighters, ashtrays out of the house on that day.
3) and this is my own invention (har, har, no, but I'm not telling where it's really from!) get post-its or colored duct tape or sticky gold stars. Whenever you have a trigger to smoke AND YOU DON"T put a star on where the trigger occurred. Soon you will be surrounded by triggers of positives rather than negatives!
Good Luck !