More than 1,500 patients age 65 and older took part in a study to determine the relationship between smoking and heart attacks. Survivors who never smoked had roughly one-half the risk of dying from a heart attack than those who kept smoking after an attack. Interestingly, even those individuals who decided to quit smoking before or after the first heart attack had a reduced mortality rate of 50% and 37%, respectively.
These reductions show similar benefits to other preventive therapies, such as lowering cholesterol, using aspirin and beta blockers. Even more striking is the fact that those who remained smokers, but cut out at least five cigarettes per day, were able to reduce their mortality risk by 18%, which is even more than using aspirin and rivals the use of beta blockers (15% versus 21%).
Source: 2009 Journal of the American College of Cardiology