Scientists suspect the process begins even before we're born. What's more, researchers have established that atherosclerosis the process that leads to arterial narrowing can begin as early as the first year of life. 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. The future of coronary artery disease and genetics This module made possible by an educational grant from DNA Sciences.