t attack is caused by the formation of a blood clot on a cholesterol plaque located on the inner wall of an artery to the heart (coronary artery). Cholesterol is a fatty chemical that is part of the outer lining of cells in the body. Cholesterol plaque is the formation of a hard, thick substance on the artery walls which is caused by deposits of cholesterol on the artery walls; a process that begins in the late teens. Over time, the accumulation of cholesterol plaque causes thickening of the artery walls and narrowing of the arteries; a process called atherosclerosis. Plaque accumulation can be accelerated by smoking, high blood pressure, elevated cholesterol, and diabetes. Ultimately, atherosclerosis causes significant narrowing of the coronary arteries. During exercise or excitement, the narrowed coronary arteries cannot increase the blood supply to meet the increased oxygen demand of the heart muscle. Heart muscle that is starved of blood oxygen, a condition called ischemia causes chest pain (angina). Chest pain that occurs with exercise is called exertional angina. Exertional angina is reversible, and subsides with rest. Occasionally, for unknown reasons, the surface of the cholesterol plaque can become sticky, causing blood clotting. When a blood clot forms on top of this plaque, the artery becomes completely blocked, causing death of the heart muscle (heart attack).Heart attack patients are monitored in the hospital for 3 to 6 days prior to discharge home. Rhythm disturbances, shortness of breath due to heart failure, or recurrent pains are indications for further therapy such as balloon angioplasty, medications, or bypass surgery. Patients gradually increase their activity under observation. Before discharge, low level stress tests are useful for detecting significant residual narrowing in the coronary arteries, rhythm changes, and heart muscle failure. They also guide the physicians in prescribing activity regimens after dischar...
