Angina Useful Info

Angina (angina pectoris - Latin for squeezing of the chest) is the chest discomfort that occurs when the blood oxygen supply to an area of the heart muscle does not meet the demand. In most cases, the lack of blood supply is due to a narrowing of the coronary arteries as a result of arteriosclerosis (see below). Angina is usually felt as a squeezing, pressure, heaviness, tightening, or aching across the chest, particularly behind the breastbone. This pain often radiates to the neck, jaw, arms, back, or even the teeth. Patients may also complain of indigestion, heartburn, weakness, sweating, nausea, cramping, and shortness of breath. Angina usually occurs during exertion, severe emotional stress, or after a heavy meal. During these periods, the heart muscle demands more blood oxygen than the narrowed coronary arteries can deliver. Angina typically lasts from 1 to 15 minutes and is relieved by rest or by placing a nitroglycerin tablet under the tongue. Nitroglycerin relaxes the blood vessels and lowers blood pressure. Both resting and nitroglycerin decrease the heart muscles demand for oxygen, thus relieving angina. Causes The most common cause of angina is coronary artery disease. A less common cause of angina is spasm of the coronary arteries. Coronary arteries supply oxygenated blood to the heart muscle. Coronary artery disease develops as cholesterol is deposited in the artery wall, causing the formation of a hard, thick substance called cholesterol plaque. The accumulation of cholesterol plaque over time causes narrowing of the coronary arteries, a process called arteriosclerosis. Arteriosclerosis can be accelerated by smoking, high blood pressure, elevated cholesterol, and diabetes. When coronary arteries become narrowed by more than 50% to 70%, they can no longer meet the increased blood oxygen demand by the heart muscle during exercise or stress. Lack of oxygen to the heart muscle causes chest pain (angina). The walls of the arteries are surrounded by muscle fibers. Rapid contraction of these muscle fibers causes a sudden narrowing (spasm) of the arteries. A spasm of the coronary arteries reduces blood to the heart muscle and causes angina. Angina is usually a warning sign of the presence of significant coronary artery disease. Patients with angina are at risk of developing a heart attack (myocardial infarction). A heart attack is the death of heart muscle precipitated by the complete blockage of a diseased coronary artery by a blood clot. During angina, the lack of oxygen (ischemia) to the heart muscle is temporary and reversible. The lack of oxygen to the heart muscle resolves and the chest pain disappears when the patient rests. The muscle damage in a heart attack is permanent. The dead muscle turns into scar tissue with healing. A scarred heart cannot pump blood as efficiently as a normal heart, and can lead to heart failure. Up to 25% of patients with significant coronary artery disease have no symptoms at all, even though they clearly lack adequate blood and oxygen supply to the heart muscle. These patients have "silent" angina. They have the same risk of heart attack as those with symptoms of angina. Diagnosis The resting electrocardiogram (EKG) is a recording of the electrical activity of the heart muscle, and can detect heart muscle which is in need of oxygen. The resting EKG is useful in showing the changes which are caused by a heart attack. It is less useful in patients with angina, since the chest pain and lack of oxygen supply to the heart only become evident during exertion or excitement.