When the arteries become blocked from blood clots or plaque, the outcome can be deadly. A potentially more serious problem than the narrowing of a coronary artery from plaque or a blood clot is the tendency of plaque to rupture and promote the formation of blood clots, causing a double assault. Any blood clot that forms on top of plaque can block the artery altogether, potentially causing permanent damage to the heart. When a part of the heart muscle dies, the outcome depends on the amount of muscle affected and the state of the arteries supplying the surrounding area.
Coronary Artery Disease
When there is an inadequate amount of blood to fill the left ventricle due to a blockage, coronary artery disease may be at fault. The buildup of plaque causes the arteries to become narrower, limiting the supply of blood to the heart. This narrowing can cause pain, breathlessness, and if severe enough, can cause a heart attack. A blockage can stop the heart muscle's action altogether, causing cardiac arrest. According to the Mayo Clinic, cholesterol-containing deposits, plaque, are usually to blame for coronary artery disease.
Atherosclerosis
If a tiny end branch of an artery becomes blocked, a small portion of the heart muscle may die. In atherosclerosis of the smaller vessels, patchy scarring occurs, sometimes without symptoms of a heart attack or pain of any kind. Ultimately, this makes the heart considerably less efficient in supplying the body with oxygenated blood. According to the National Heart, Lung and Blood Institute, for blockages in large and small arteries, a surgical procedure called a coronary artery bypass graft, or CABG, involves removing a vein or artery--usually from the leg--and grafting it to the blocked coronary artery. The new artery essentially bypasses the blockage, restoring blood flow to the heart.
Variant Angina
In addition to blockage of the coronary arteries by a blood clot, a coronary spasm can also cause heart failure. The coronary arteries begin to spasm because of a disorder called variant angina. The wall of the artery expands and contracts, causing a spasm that blocks and then releases blood into the heart. According to the National Heart, Lung and Blood Institute, these spasms can also block blood flow long enough to stop the heart completely.
Treatment
Immediately administering thrombolytic medications to treat a heart attack has shown to reduce the damage caused by a blocked artery. According to the U.S. National Library of Medicine, receiving a thrombolytic drug within 90 minutes of a heart attack greatly increases the chances of survival and minimizes damage to the heart. However, using these drugs substantially increases the risk of hemorrhage or bleeding--which can be just as life-threatening as the initial heart attack.
