When most people refer to heart disease, they are referring to coronary heart disease. Cholesterol, calcium, fat, and other substances form a waxy substance called plaque, which can build up on the walls of your arteries. Plaque deposits limit blood flow and increase the risk of heart attack and other serious complications. A plaque deposit can also rupture, causing a blood clot that completely blocks blood flow in the affected artery. If you experience chest pains, jaw pain, pain in your left arm, or any other signs or symptoms of a heart attack, seek immediate medical attention.