When does the heart attack occur?

A heart attack, also known as a myocardial infarction, happens when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle. The most common cause of a heart attack is a buildup of plaque, made up of cholesterol, fat, calcium, and other substances, in the coronary arteries. This plaque can narrow the arteries and make it difficult for blood to flow through them. If the plaque ruptures or tears, it can cause a blood clot to form, which can block the artery and stop blood flow to the heart.