Cardiac disorders are especially associated with atherosclerosis (ath"er-o"skle-ro'sis), an accumulation of soft masses of fatty materials, particularly cholesterol, beneath the inner linings of the arteries. Such deposits are called plaque (plak), and as they develop, they tend to protrude into the vessel and interfere with blood flow. As discussed in the MedAlert reading on this page, diet can be used to control blood cholesterol level, and therefore plaque, when necessary.
If the coronary artery is partially occluded (blocked) by the presence of atherosclerosis, the in-
dividual may suffer from ischemic (is-kem'ik) heart disease. Although enough oxygen may normally reach the heart, the individual experiences insufficiency during exercise or stress. At that time, the individual may suffer angina pectoris (an-ji'nah pek'to-ris), chest pain that is often accompanied by a radiating pain in the left arm.
Sometimes blood clots in an unbroken blood vessel particularly if plaque is present. A thrombus is a stationary blood clot in an unbroken blood vessel, and an embolus is a blood clot that is moving along in the bloodstream. Thromboembolism is present when a blood clot breaks away from its place of origin and is carried to a new location. Thromboembolism leads to heart attacks when the embolus blocks a coronary artery and a portion of the heart dies due to lack of oxygen. Dead tissue is called an infarct, and therefore, the individual who has had a heart attack has had a myocardial infarction (mi" 0- kar' de-al in-fark'shun).
Myocardial infarction is often preceded by atherosclerosis, angina pectoris, and thromboembolism.
Two surgical procedures are associated with occluded coronary arteries. In thrombolytic therapy, a plastic tube is threaded into an artery of an arm or leg and is guided through a major blood vessel toward the heart. Once the tube reaches a blockage, a balloon attached to the end of the tube can be inflated to break up the clot, a procedure called balloon angioplasty. In some cases, a small metalmesh cylinder called a vascular stent is inserted into a blood vessel during balloon angioplasty. The stent functions to hold the vessel open and decreases the risk of future occlusion. Alternately, streptokinase may be injected to dissolve the clot. In a coronary bypass operation, a portion of a blood vessel from another part of the body, such as a large vein in the leg, is sutured from the aorta to the coronary artery, past the point of obstruction. This procedure allows blood to flow normally again from the aorta to the heart.
January 18, 2011