I think a lot of other factors play into the answer for this question. But one fact is, smoking is one of the modifiable risk factors for heart attack and stroke. (Weight/Diet and exercise being another.) The nicotine present in smoke causes: - Decreased oxygen to the heart. - Increased blood pressure and heart rate. - Increase in blood clotting. - Damage to cells that line coronary arteries and other blood vessels. Someone with a known history of coronary disease with a previous heart attack has to quit smoking, period. Otherwise, I'd say it's just a gamble.