The scientific name for a heart attack is “myocardial infarction”. This occurs when blood flow to a part of your heart is interruption for a long enough time that part of the heart muscle is damaged or dies.
This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, which is an unstable collection of lipids (cholesterol and fatty acids) and white blood cells in the wall of an artery. The resulting restriction of blood supply results in an oxygen shortage, and if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium).
A recent study has shown that you can predict how likely you are to have a heart attack by having a computer tomography (CT) scan which looks for calcium build up in the arteries. This happens as a result of the arteries hardening due to a build up of fats and cholesterol. Those with calcium build up were found to have a risk 4 times higher than those that didn’t. Some experts believe that this is the best predictor of a heart attack, but others believe that it’s risky and that other tests are better. This sort of discussion pushes science forward, though.