WHAT HAPPENS DURING A HEART ATTACK?

A closer look inside your coronary arteries Your heart muscle needs to receive a good supply of blood at all times to function properly. Your heart muscle gets the blood it needs to do its job from the coronary arteries. What is coronary artery disease? Coronary artery disease is the narrowing or blockage of the coronary arteries caused by atherosclerosis. Atherosclerosis (sometimes called “hardening” or “clogging” of the arteries) is the buildup of cholesterol and fatty deposits (called plaque) on the inner walls of the arteries that restricts blood flow to the heart. Without adequate blood, the heart becomes starved of oxygen and the vital nutrients it needs to work properly. This can cause chest pain called angina. When one or more of the coronary arteries are completely blocked, a heart attack (injury to the heart muscle) may occur. A closer look at coronary artery disease
When fat builds up inside your arteries it causes slight injury to your blood vessel walls. In an attempt to heal the blood vessel walls, the cells release chemicals that make the blood vessel walls stickier. Other substances traveling through your blood stream, such as inflammatory cells, cellular waste products, proteins and calcium, begin to stick to the vessel walls. The fat and other substances combine to form a material called plaque.
Over time, the inside of the arteries develop plaques of different sizes. Many of the plaque deposits are soft on the inside with a hard fibrous “cap” covering the outside. If the hard surface cracks or tears, the soft, fatty inside is exposed. Platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque.
If a blood clot totally blocks the blood supply to the heart muscle, called a coronary thrombus or coronary occlusion, the heart muscle becomes "starved" for oxygen and nutrients (called ischemia) in the region below the blockage. Within a short time, an acute coronary syndrome can occur. Acute Coronary Syndrome is a name given to three types of coronary artery disease that are associated with sudden rupture of plaque inside the coronary artery: unstable angina, Non-ST segment elevation myocardial infarction or heart attack(NSTEMI),or ST segment elevation myocardial infarction or heart attack(STEMI).
spasm A heart attack can also occur less frequently by a spasm of a coronary artery. During coronary spasm, the coronary arteries constrict or spasm on and off, causing lack of blood supply to the heart muscle (ischemia). It may occur at rest and can even occur in people without significant coronary artery disease. If coronary artery spasm occurs for a long period of time, a heart attack can occur.
Each coronary artery supplies blood to a region of the heart muscle. If an artery is occluded (blocked) there is no blood supply to that region.
dark red = artery	blue = outlines region of heart affected by blockage
Circumflex occlusion back of heart	Left anterior descending (LAD) occlusion front of heart	Right coronary artery (RCA) occlusion front of heart
The amount of damage to the heart muscle depends on the size of the area supplied by the blocked artery and the time between injury and treatment. Quick treatment to open the blocked artery is essential to lessen the amount of damage. Learn the symptoms of a heart attack and what to do if they occur. Healing of the heart muscle begins soon after a heart attack and takes about 8 weeks. Just like a skin wound, the heart’s wound heals and a scar will form in the damaged area. The new scar tissue does not contract or pump as well as healthy heart muscle tissue. So, the heart’s pumping ability is lessened. The amount of lost pumping ability depends on the size and location of the scar.