Clogging or narrowing of the arteries results from a complicated interaction of these systems listed above. Scientists suspect the process begins even before we're born. Once established, the narrowing of the arteries grows unevenly over time. For example, it can grow slowly for decades then increase its growth rate. As the narrowing grows, it increasingly limits the flow of blood through the artery.
Chest pains occur when the heart requires more blood than can flow through the narrowing.
A heart attack is a sudden event that occurs when blood flow through an artery is completely blocked. Heart attacks are usually not caused by gradual narrowing of an artery. They are usually caused by a blood clot forming at the site of a narrowing. Coronary artery disease and your family history . Your risk is higher if your relative developed coronary disease at an early age.