@gingerplum - what's the easiest way to bring on a fatal heart attack?
I'd say be an obese 60 yr-old male, with a history of high blood pressure, excessive smoking, high blood cholesterol, and diabetes. Double bonus points if you're in complete kidney failure.
A heart attack is a myocardial infarction-- an area of heart tissue becomes ischemic (oxygen deprived). It's very painful and not a fun way to go. Symptoms include dizziness, fatigue, lightheadedness, clammy skin, cold sweat, sweating, anxiety, nausea, vomiting, pressure, feeling of impending doom, palpitations, and shortness of breath.
It's nearly impossible to induce an MI in an otherwise healthy heart; people have suggested overdosing on caffeine, which would have to be incredibly terrifying and distressing and probably wouldn't work. Heart attacks also aren't necessarily fatal, and surviving a serious one will leave you with permanent disabilities and co-morbid conditions.
Stabbing yourself in the chest would be a better plan, but I don't recommend that, either. Nope the fuck away from this idea, please.